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TR-27 GRYPHON - CR-18 Rapidstrike Mod

Modes: 3-Burst, Auto, and Precision Shooting mode! + Ammo Counter

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#1 Technician Gimmick

Technician Gimmick

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Posted 12 May 2014 - 09:48 PM

EDIT 7-11-14: I have received quite a few request for full resolution photos of my project, so I am sharing the link to my photo album. Full Res Photos


Hello everybody!

My friends have been pestering me to share my latest project with you all, as they believe it is so cool that just can’t keep it to myself. I will leave it to you to decide.

HISTORY
Before we go into the details of how this mod, let me give you a smidgen of history. A close friend of mine recently started hosting Nerf games on the weekends and once our group started growing, he decided to invest in a Rapidstrike CS-18 Nerf Blaster. He had seen Coop772’s youtube video, showing how he modifying his Rapidstrike, and was interested in doing something similar.

Knowing that I was into electronics, he asked if I would be willing to look it over with him, and see what we could do to boost the rate and speed of fire. (Only without burning out the motors) We started with a simple voltage boost to run the motors faster. But after looking at how this blaster was made, and seeing all of the components, I started to realize just how much potential this blaster really has.

So, I purchased my own, and the project began.

About Me
I am new to this sport, but it I find it is very similar to paintball. And although it has been quite a while since I’ve played, I find that many of the tactics apply. Just like many of you, I think Nerf and I will have a very bright and fun future together.

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This is the TR-27 Gryphon. It is a fully modified Rapidstrike CS-18, featuring a microprocessor controlled double digit ammo counter that can automatically recognize and display the capacities of multiple types of magazines.

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It has 3 unique modes; 3-burst, fully automatic, and "Precision Shooting" I have designed it specifically for functionality and game play, not necessarily aesthetics. Although I think the paint job was a pretty cool touch **grin**

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This blaster is powered by a Lithium-Polymer battery that is capable of boosting the flywheels up to full speed in 3/10th of a second, as well as achieve firing rates of nearly 7 darts per second.

This means you won’t have to wait for those flywheels to spin up before you can return fire, or spring from your ambush hiding spot. Unlike the original Rapidstrike, you won’t have to walk around with the flywheels running; giving away your position and wasting your battery life.

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3-Burst Mode
3 DART BURST AT 7DPS

http://youtu.be/n2xjWE69xpA

Aside from just being cool, this mode was designed for attacking.

Snippet about 3-Burst: The 3-burst concept was made popular with the M16 assault rifle widely used in Vietnam. A fully automatic rifle typically has so much recoil, that after firing much more than 3 rounds, a soldier needs to stop, and re-aim. Failing to do this results in very poor accuracy, and is also a massive waste of ammunition. 3-Burst was designed to allow the soldier to re-aim between bursts, and to conserve ammunition.

Unlike the M16, the goal of the TR-27’s 3-burst mode is to push the blaster to its max, while still allowing enough time for the motors to cool down. Tactically, this is an excellent point and click style tool, almost eliminating the issue of dart inaccuracy. This is without a doubt my favorite in-game mode.

From standby, the first trigger pull will bring the flywheels up to full speed in 300ms (milliseconds) if the trigger is still held in at the end of the 300ms, it begins to burst fire. If not, the blaster watches for a trigger pull and keeps the flywheels up to speed for 2.5 seconds before going back to standby. The burst shot will immediately fire 3 darts at a rate of almost 7dps (darts per second), followed by a 300ms delay before you may repeat the process, and fire again.

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Mode selector switch set to burst mode

Automatic Mode
SINGLE OR CONTINUOUS STREAM OF DARTS AT A RATE OF 4 DPS
You can find the rest of my videos for this blaster on youtube
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Mode selector switch set to auto mode
This mode is designed specifically for defense and allows you to conserve your ammunition while still keeping your foes hiding behind their cover.

Again, from standby, the first trigger pull will bring the flywheels up to full speed in 300ms. If the trigger is still held in at the end of the 300ms, it begins firing. After the dart has been fired, the gun has a 100ms delay before you may repeat the process.

Thanks to my friend’s input on the matter though, you have 2 options for continued fire after the flywheel is up to speed. It’s sort of a mix between automatic and single fire. If you hold the trigger down, the gun will begin another shot at the end of the delay from the previous shot.

Alternatively, you may pull the trigger repeatedly, and the blaster will count how many times you have pulled the trigger, and add to the firing cue. This means, starting from standby, you could pull the trigger 19 times, as fast as you can, and the blaster will spin up and fire all 18 darts.

Note about delays: Both 3-burst and auto have delays at the end of either a 3-burts shot, or a single fire/full auto shot. This is done on purpose for two reasons. First is so they both take roughly 4.5 seconds to empty an 18 round mag. Second, and more importantly, the delays are to keep the motors from overheating and either shortening the motor’s life, or even burning them out. Even though the two modes empty the mag in the same amount of time, they both have their strengths and weaknesses.


"Precision Shooting Mode"
Note to the Moderator

2 DART BURST WITH THE FLYWHEELS RUNNING AT ABSOLUTE MAXIMUM SPEED
You can find the rest of my videos for this blaster on youtube
Yes, we added "precision shooting" mode! This was born from my fond memories of playing Team Fortress Classic with my brothers. I was (you guessed it) the Precision Shooter, and I simply loved having showdowns with my brother (who was also a Precision Shooter), holding down the mouse button as the gun charges, waiting to see his head, and BANG! I like to think I beat him more often than he beat me, but I might just be trying to fooling myself.

Anyways, people often develop a false sense of security at a distance as so many darts fall short, or are just slow. This mode is designed to take advantage of that mindset. The higher speed that the dart travels through the air, combined with the fact that it bursts 2 darts, makes this mode much harder to dodge. A dart at this speed can really pack a punch, and the closer to the gun you are, the more punch you get, so I gave this mode a long spin up time to deter people from using it in confined/up close spaces.

Like TFC, this mode operates in the same way you would hold the mouse button down to charge the gun. From standby, you hold the trigger down, and the blaster begins to spin up the flywheels. In 3 seconds, the blaster will reach its full speed, running the motors at the full 12 volts, and will continue to run at that speed for 2 seconds longer. At any time during the spin up process, you may release the trigger, and the blaster will fire the 2 darts, and then delay 2.5 seconds before you may repeat the process or switch modes. Again, this delay is to prevent the motors from overheating. To prevent jams, the blaster will not fire on trigger release until it reaches its minimum speed, to ensure the dart won’t get stuck in the barrel or flywheels.

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Mode selector switch set to "precision shooting" mode

Empty the Gun Mode
FIRES EVERYTHING AS FAST AS IT POSSIBLY CAN
You can find the rest of my videos for this blaster on youtube
Naturally, when something as cool as the Rapidstrike is controlled by a computer, the thing to do is push it to its limits, and see just how fast one can empty the gun. And in that vein of thought, I made “Empty the Gun” mode. With the throttles opened all the way, this TR-27 can empty an 18 round mag in as little as 2.7 seconds. Later in the project we achieved 2.2 seconds (little over 8 shots per second) However the smell of ozone made me think that this was putting the motors at risk of burning out.

This mode is limited in the following way. First, once you pull the trigger, it runs until it is empty. Second, it will only work with marked mags. So at most, you can only do a 35 round mag in one go. Third, you have to enter a code (sequence of trigger and warmup trigger pulls) in order to activate this mode. And it takes so long to enter the code that the motors have plenty of time to cool down.

Like I said, I designed the TR-27 for functionality and game play, and this mode is no exception. It serves little to no purpose in-game because it drains all of your ammo, and requires a lot of down time to protect the motors from burning up. However, the pure intimidation factor gives you quite the tactical advantage. Simply fire off a mag in this mode before game play starts, and everyone will have that image in their minds for the rest of the day; especially if they are on the opposing team. (Am I sneaky or what? **Evil Laugh**)


AMMO COUNTER DISPLAY
The TR-27 is fitted with two common cathode 7-segment displays in beautiful blue. You may turn off, or set the display by simply sliding back the access cover, and pulling the trigger. It has been programed so the first trigger pull will turn off the display, and every subsequent pull will increment the screen’s brightness up through the 15 levels of brightness. This way, you can quickly turn off your display if you find yourself trying to hide in a dark place.

Level 5 is pretty nice indoors; however I find that the light can be distracting if you are sighting down the top rail or through the red dot sight. Indoors, I typically play at brightness level 2. Level 15 is super bright, and great for outdoor game play when you are out in the sun.

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Ammo Counter after inserting an 18 round magazine


MAGAZINE DETECTION
Upon insertion of a marked magazine, the blaster will detect that ammunition is available, and depending upon the type of mag, will automatically set the ammo counter to the capacity of the mag. If an un-marked mag is inserted, the blaster will still detect that ammunition is available. However not knowing what capacity it holds, it starts the ammo counter in count up mode. This way when you play with your friends and use their mags, you can at least know how much ammo you have fired out of unmarked mag.

To date, the blaster is capable of recognizing 6, 10, 12, 18, 25, and 35 round mags after they have been “marked”. Marking a mag is very simple. There are 3 magnetic sensors inside the blaster that read the presents or absence of the magnets, and can then determine what capacity it is. (I am considering adding a 5 round clip for those of you who have done the “mini-clip” mod on your 6 round mags.)

From here on in, this stuff gets a little dry for most people. However if you are technically minded, want to learn something new, or just really excited about this blaster, read on!


SAFETY, MALFUNCTIONS, & ERROR CORRECTION

Slow Ammo Feed: The blaster uses infrared to watch the ammo at the top of the magazine, and will halt firing if no ammunition is available. Slow feeding occurs if your darts are either falling apart, or have been loaded in the mag in such a way as the tips rub up against the front edge of the mag. Consequentially, they do not feed as fast as the blaster is able to fire.

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You can find the rest of my videos for this blaster on youtube

Piston Fails to Stop Soon Enough: There are times when the piston will fail to stop on time, and will coast back into the firing chamber. If the ammo has expired, then the blaster will auto correct by running the plunger at low speed until it has seated back in the ready position.

In the cases where there are still darts available to fire, the blaster ceases to fire, and indicates the malfunction to the user by blinking the ammo counter on and off. This malfunction may be cleared by removing the mag, thus expiring the ammo and allowing the blaster to auto correct. However, there are times when the jammed dart stays in the chamber, preventing the plunger from resetting itself. If this happens, you only need to open the access cover, and remove the dart by hand.

Bent Dart Jams: A jam common to darts that are flattened/squished/or have limp necks is when the tip gets folded over just before entering the flywheels. I have not yet determined if this is due to the piston pushing the dart forward before it is all the way out of the mag, or if it is something else. I have however recently programmed the blaster to delay 30ms if it senses that no darts are available to fire. This should allow just enough time for the slow feeding dart to make it to the top of the mag, before the piston begins to fire again. I’ll try to let you know if I notice any improvement on the matter.

Slowing Speeds Due to High Shooting Volumes: This issue really isn’t an issue. But I thought you’d like to know that it has been taken care of. Each time the piston pushes another dart into the flywheels, the flywheel motors are supplied with a 50ms burst of high voltage in order to maintain a regular dart speed. As I will explain a little further on, Nerf solved this problem by supplying the flywheels with roughly 4.5volts for warm up and standby of the flywheels, and the full 6volts only when the trigger is being pulled.

Display Shows Gibberish: This has happened from time to time, and is relatively easy to correct. Simply reset the blaster by removing the mag, and flipping the on/off switch located inside the mag slot. The cause of this is electrical. I have been working for some time to eliminate this entirely, but for now it remains an occasional annoyance.

INTERNAL COUNTERS
The blaster has internal counters that record how many shots have been fired, and how many reloads have occurred. In further revisions, I will probably add more counters to record things such as jams, lid opens, time spent in each mode, etc… But please keep in mind, I already have over 300 hours invested in the 800 lines of code for this blaster. I’m embarrassed to say that I’ve worked on it so much that my wife has nicknamed it “the other woman”.

ELECTRICAL DIAGRAM
I started by diagramming the entire electrical system of the original CS-18 to see if I could incorporate any of the original wiring.
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With a little fuse, all of the electrical components may be removed without unsoldering, or cutting any wires. It took time, but I eventually traced every wire, and made my diagram.

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The diagram isn’t 100% complete, however it can give you a good understanding of how the blaster functions

The original Rapidstrike is designed so when the flywheel trigger is pulled, the flywheel motors are powered through the two diodes (D1 & D2) and the flywheels come up to speed. The diodes serve to lower the voltage a few volts so the flywheels don’t spin at full speed.

I’m sure the reason that Nerf has the diodes, is to prevent the flywheels from reaching a speed, under no-load, that would make lawyers uncomfortable. The full 6 volts are only applied when the trigger is pulled and the piston is running. It is the load of the darts that keep the flywheels from reaching that “uncomfortable” speed.

Besides, if they had run the flywheels at full, and then started feeding darts through it, the first 3 darts would be really fast, but then the continued load would slow down to what the blaster fires normally. This perceived slowing of the darts would ultimately lead to the user feeling cheated.

SIMPLE MODIFICATION
However, if you view it as getting 3 fast darts and 15 regular darts, instead of 3 normal darts, and 15 slow darts, then a very simple modification would be to bypass the diodes and prevent the voltage drop.

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The two diodes are difficult to see just looking at the blaster. They are mounted on the PCB just forward of the trigger, on the reverse side.

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The simple mod would be to solder a wire running from where the yellow and brown wires connect, to the solder connection in the upper right corner of the PCB, where the red wire connects.


Bypassing the diodes should allow the blaster to spin up in far less time than previously. (But still not as fast as the TR-27 does)

Back to their design, it is interesting to note what they did for the piston motor. They are using a motor braking system to prevent the motor from drifting past the stopping point and entering the firing chamber after firing has finished.

Quick Snippet about motor brake: A motor brake is a method for quickly slowing down an electric motor. Motors are almost the same as generators. If you hand crank a motor, it will generate a current on its leads. And just like a generator, the greater the load, the more resistance you will have on the shaft. So, in order the get that motor to stop coasting as quick as possible, you need to put the maximum load possible on the leads. Which would be a direct short across the leads.


As it turned out, I didn’t end up using any of the original wiring; however the motor brake was a definite must in the TR-27.

TR-27 MOTOR BRAKE

The piston in this system has been the most troublesome part in it. Yes, you can send some pretty high voltage to the motors to get them to go faster, but that doesn’t make them stop any faster. The TR-27 sends an 80ms burst of 12 Volts to the piston motor, immediately followed by 20ms of braking.

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That means it puts the brakes on just as the piston begins to return to its ready position. Then it continues running at 5 volts until the piston stop switch is pressed as the piston seats in the ready position.

I have considered putting in a faster motor to run the piston, however it would still have the problem of not stopping soon enough.

Even with the pre-brake I’ve programmed in, my normal motor is coasting past its stopping point from time to time. My hopes are that I can either read more precisely where the piston head is located based on more than just the stop switch, or that I can burst the motor in reverse for a couple milliseconds, instead of using the brake. This is pending the installation of a full H-Bridge controller.

HARDWARE

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11.1 volt Lithium-Polymer Batter, Arduino Pro Mini, Power Switch, Mode Switch, 7-Segment Displays, MAX7219 Segment Driver, Diodes, MOSFETTs (to run the motors), Micro Relay (for motor brake), Magnetic Reed Switches (for detecting mag capacity), Neodymium Magnets (for marking the mags)


This list was missing the infrared sensor that is used to detect ammo, as well as a 5 volt regulator I have added in an attempt to solve the display gibberish problem.

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Infrared Sensor 5 Volt Regulator


TR-27 MICROCONTROLLER & DIAGRAM
Like you read earlier, this blaster fitted with a microcontroller. It is an Atmega328P mounted on the Arduino Pro Mini.

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Microcontroller ATmega328P


This Arduino has no USB, and must be programmed with an external TTL device.

While this is a little more inconvenient, it does lower the cost of the board, and seeing as I ended up killing 2 of these boards in the making, I don’t mind so much. These may be purchased from the world wide garage sale, (eBay) as can almost every component that I have used in this blaster.

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TR-27 GRYPHON electrical schematic

View in Full Res

This diagram is very close to what I actually have in the blaster. There are a few minor differences because the program I used to diagram this doesn’t have all of the components I used in the blaster. So in this they are replaced with simple switches or something similar. The function remains almost the same.

Known Differences:
-There are now 3 reed switches detecting the capacity of the ammo.

-There is another board installed on the blaster that monitors the LiPo battery and discontinues use when the battery level is too low. This is to prevent the battery from being destroyed.

-Both of my flywheel motors are still powered through the built in resistors and the current limiter.

-There are capacitors installed on the 5 volt line to help prevent spikes that interfere with communication between the Atmega328 and the MAX7219 led segment controller.

-The IR LED no longer has a transistor, or is powered from the 12 volt rail.


SWITCHES

All of the original switches have been wired to the pins on the Arduino, and when pressed they pull the pins LOW (0 volts). In the programming, they are initiated as “INPUT_PULLUP”. This means the Arduino internally pulls the pin HIGH (5 volts), and watches to see if the pin is pulled LOW through external means.

Snippet about Microprocessors and switches: It is common practice in electrical design to use a pull down resistor to pull the pin LOW, and then have a button/switch that will supply 5 volts that will pull the pin HIGH when pressed. While the external pull down resistor method is probably a safer way to go; in that it will be less likely to be damaged by electrical shock. But my limited space makes the internal pull up resistor much more convenient. And because of the way Nerf built the switches, I feel pretty safe when it comes to electrical shock (Static electricity).

I had to remove all of the mechanical locks inside the trigger assembly in order to allow all of the switches to be used independent of each other.

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There is one that prevents the trigger from being pulled unless there is a mag inserted. And there is another that prevents the trigger from being pulled unless the warm up trigger is held in.

Trigger lock to prevent trigger from being pulled unless a magazine is inserted.

The main safety switch (SW1 in the original’s diagram) has also been removed, and that location is now used as the primary on/off switch for the blaster.

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Rapidstrike’s Main Safety Switch TR-27’s Primary On/Off Switch



SWITCH PROGRAMMING

Okay, something you need to know about buttons/switches connected to microcontrollers. Microcontrollers are fast. Really fast. One of the problems that programmers must overcome is called debounce.

When a button is pressed, the voltage on the digital pin doesn’t just change from 0 volts to 5 volts. The button actually bounces, letting a fluctuation of voltage go to the pin. And since the microcontroller is so fast, it would see a single button press as 3 or 4 button presses.

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Naturally there is a way to overcome this. Typically programmers have their code look at the pin, and when it sees a change, check back with it in a couple milliseconds. And if it is still the same, it assumes a button has been pressed, or released.

For the TR-27, it checks the buttons every 5 milliseconds, and it stores a running average of the last 10 readings. When the average of a button is higher than 5 it then considers the button to be pressed.

Not only does this take care of the debounce issue that happens when a button is pressed or released, but it also takes care of any mini spikes/dropouts that might happen while a button is being pressed.

In addition, not all switches/buttons are check all the time. For instance, the blaster doesn’t pay attention to the reed switches unless it detects that ammo is available or has been removed.


REED SWITCHES (MAGNETIC SENSORS)

Two of the reed switches are mounted behind the mag guide, and third is mounted behind the wire cover. They interface with the Arduino the same as the others do, by pulling the pin LOW (0 volts), when a magnetic field is sensed.

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With 3 read switches, the blaster may recognize as many as 7 different magazine capacities, depending on where and how many magnets are glued to the magazine. We have really put a lot of thought into every aspect of this blaster. To save on the cost of magnets, both the 6, 18, and 35 round magazines only require 1 magnet to be recognized. While the 12 and 25, being less common, need 2 magnets to be identified.

MULTI-INPUTS ON A SINGLE PIN

Funds and time allowing, future TR-27s will have all 3 reed switches connected to a single pin. This will allow me to pack even MORE stuff inside this blaster, as I am rapidly running out of available pins.

I have already made a working prototype for testing this new method.

The concept is basic. You have button that when pressed add a preset amount to a measurable total.

Button A = 1
Button B = 2
Button C = 3


And your total is 1, then naturally, button A is being pressed.

2 = B
3 = C
5 = B + C
6 = A + B + C


Simple, right? Well, not quite. If the total was 3, you wouldn’t be able to tell if buttons A and B are being pressed, or if button C is being pressed. The solution to this is to use multiples as your values. So A = 1, B = 2, C = 4. Now you can take the total, and figure out exactly what buttons are being pressed.

In electricity though, it gets a little more complicated, and the math becomes difficult to be exact. A standard “gold” resistor is accurate within 5% of its rated value. And you must have a common resister used as a pull-down resistor in the circuit as well. And to complicate things further, you can’t get resisters of exact multiples in rated value; at least not easily.

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So, instead of trying to do the math, I made a funnel kind of measuring system instead. My reed switches are hooked to; 1.1k, 2.2k, and 4.7k resistors with a common 1k pull-down resistor. These are close to multiples, so I can still distinguish between buttons A+B and button C. The voltage is fed into the Arduino on an analog pin.

Note about analog reading on the Arduino: The Arduino board contains an 8 channel, 10-bit analog to digital converter. This means that it will map input voltages between 0 and 5 volts into integer values between 0 and 1023. This yields a resolution between readings of: 5 volts / 1024 units or, .0049 volts (4.9 mV) per unit.

After I made the prototype circuit, I pressed the buttons one by one in every possible combination, and recorded their values. Then I did the math to find the middle point between each reading, and then I arranged a large “if, else if”, block of code that “funnels” the reading into understandable information.

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Not too bad for 3 switches, but the more you add to the system, the tighter your tolerances become, and the more possible combinations there will be to take readings on, and find the corresponding range.

INFRARED SENSOR

Originally I had used an IR sensor taken from the scroll wheel of a mouse, however now I have a smaller one that I bought in bulk from our favorite worldwide garage sale. Electrically it’s a rather simple sensor. It works exactly like a transistor (probably why they are known as photo transistors…), but instead of having signal lead, it uses infrared light to activate the gate.

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Meaning you hook one side to 5 volts, and the other to a digital pin on the Arduino that is being pulled LOW with a 10k resistor. When Infrared light enters the sensor, it sends a very small current into the gate, allowing the larger 5 volts to flow through the sensor, and into the pin on the Arduino.

Back when I was using the mouse sensor, I had a much larger Infrared LED, for sending the IR light to the sensor. In fact it drew so much more current that I had to power it from the 12 Volt line, because the onboard regulator on the Arduino wasn’t able to handle it. Later I realized I was burning up a lot of energy in the resistors I used to step the 12 Volts down to run the LED. So, in order to solve that, I added a transistor that would control the LED, so I could turn it on and off only when taking a reading.

It was a nice improvement, but the smaller ones are still better.

WIRING

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Nearly all of my wiring is on the right half of the blaster, just like Nerf did theirs. However I have 2 items located on the left side of the blaster that I have run wires to. The Infrared LED, and the mode switch; wiring for those run through pins that I have glued on either side. And when the blaster is assembled, they plug into each other very well.

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BATTERY TRAY & BATTERY MONITOR

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This pin idea worked so well for wiring from one side of the blaster to the other that I decided to use it for the battery tray too. The pins on the back are used to monitor each cell of the batter, as well as (eventually) turn on and off the flashlight mounted in the front.

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FUTURE PLANS
This blaster has been so fun to work on, and I just don’t want the fun to stop. But my wife and wallet are complaining. I do hope to incorporate the following in future designs though.

BLUETOOTH: A smartphone controlled Nerf Blaster! Just imagine the possibilities. Remote controlled firing for starting an ambush triggered by motion detected on your smartphone’s camera! Turn the flashlight on/off remotely. Loan your gun to your friend, and then turn on the safety! (evil laugh!)

The Arduino lends itself to Bluetooth rather well. However it will require tons more programming to make the blaster compatible to outside commands and then! THEN! I’ll have to learn how to make apps for smartphones… This could be a ways away.

OLED SCREEN: I have already ordered a 128x64 monochrome OLED and I intend to replace the blue 7-segment displays with it. Then I can show what mode the gun is it, what size mag is inserted, how much ammo is remaining, better notification to jams. Plus possible diagnostics and tuning. Maybe a personal score keeper system??

LASER: Lasers are nice because you can shoot from the hip and still aim. Plus they just look cool!

STROBE FLASHLIGHT: Once I finally get the front flashlight working, I will definitely be able to add a strobe mode. I could even time it to flash just after a dart exit barrel.

JAM CONTROL: I am also hoping to install another infrared sensor just after the flywheels so the microcontroller can tell if the dart actually made it out of the blaster.

I am open to new ideas. Either features you’d like to see, or improvements for what it is now. Please post them!

For those of you who read through the whole thing, I applaud you. I’m long winded, but I hope you found it entertaining and informative. Perhaps too informative…

Thank you all!
- Gimmick

Edited by Technician Gimmick, 11 July 2014 - 07:41 PM.

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#2 Luckydude7

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Posted 12 May 2014 - 10:28 PM

Dude. This is the coolest blaster I've ever seen. I will give you money, no strings attached, just to see you get those new screens and toys fitted on.
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#3 He Who Mods

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Posted 12 May 2014 - 10:28 PM

Wow. Probably the most in-depth overview/writeup I have ever seen. The blaster is awesome too. Hope we can see more things from you soon!!!
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#4 Zack Dorris

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Posted 12 May 2014 - 10:40 PM

Wow, you have completely made the rapid strike just amazing. I am speechless with all the time and effort you put into this. I hope in the future someone maybe you does something like this to a Stryfe. Keep up the great work man. Your workmanship is amazing.
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#5 Thorn

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Posted 12 May 2014 - 10:55 PM

That is brilliant. I especially like the dart sensing mechanism. Huge props on the modification, and I eagerly look forward to future modifications of yours.

Edited by Thorn, 12 May 2014 - 10:56 PM.

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#6 Bee-Ri

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Posted 13 May 2014 - 04:56 AM

Is there any way to increase the firing speed of the automatic mode without emptying
the magazine? For example a potentiometer or a PWM circuit to control the pusher speed.

Also, do you plan on making the code available? It would be interesting to read the code
and possibly adapt it to work with something like a Nitron.

Anyway, this is a very nice blaster.
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So I see you've noticed my signature.
It is pretty boring.

#7 DORKSABER

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Posted 13 May 2014 - 12:16 PM

Nice work. I've built a very similar rapidstrike for myself, and as a commission for a few folks. Pretty much every function you have here except for your automatic flywheel control, and magazine recognition (I don't believe in modifying magazines).

Here's a video of one of the commissions I did a few months ago: http://youtu.be/2qwLHp6HKm0?t=30s

Why didn't you install your 7 segment display flush with the rear surface?

I've also been considering using an OLED display, since I'd like to show the firing mode and total magazine capacity, in addition to the current ammo count. I haven't really thought aobut the other stats to display, though I think that's also kind of unnecessary. I haven't had the money to pursue this as of late, unfortunately.

While I don't like the thought of a cellphone controlled blaster (unless it's like an autonomous turret), there have been a couple people who've asked me about integrating their blaster with an HUD for a Google Glass sort of device. What do you think about that sort of thing?

Edited by D4RK354B3R, 13 May 2014 - 12:24 PM.

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#8 roboman

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Posted 13 May 2014 - 12:33 PM

Damn, you beat me to it. This is pretty much exactly what I've been (very slowly) working on for quite some time, though I'm planning on going with the custom PCB route to entirely replace the trigger assembly and eliminate most of the wires you have running through the shell. Why are you planning on replacing the power transistors with an H-bridge? You shouldn't ever have to reverse any of the motors, so a power transistor should work just fine.

Would you mind posting your code or a link to Github or something? I'm interested to see how you did it.
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#9 awsome

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Posted 13 May 2014 - 06:16 PM

Mind blowing! This is most likely the most "technological" rapidstrike that I've ever seen
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#10 Rommel McDonald

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Posted 13 May 2014 - 09:41 PM

Great write-up, insane build. Freaking awesome. I just had a Nerfgasm.

Edited by Rommel McDonald, 13 May 2014 - 09:42 PM.

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#11 Technician Gimmick

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Posted 13 May 2014 - 11:24 PM

Wow, I'm glad you all liked it so much. It really has been a very fun project to work on.


roboman

Why are you planning on replacing the power transistors with an H-bridge? You shouldn't ever have to reverse any
of the motors, so a power transistor should work just fine.


The piston motor must have a motor brake in order to stop fast enough that you only fire 1 dart. I did some testing to see just how effective the brake was. I ran the motor at full speed for 1 revolution, and then let it coast. After that single revolution, it coasted 2 and a half more without power.

So far I have been using a micro relay to engage the motor brake, and a MOSFETT to control the speed of the motor. I'm going to experiment with an H-Bridge for two reasons. First, it has a built in braking system that unlike the micro relay, will not interfere with communications between the Arduino and the Max7219 LED controller. Second, I am considering using reverse to stop the motor even faster than the motor brake could. (Yes, I know this will put a lot of stress on the motor.)

D4RK354B3R

...(I don't believe in modifying magazines)...

...Why didn't you install your 7 segment display flush with the rear surface?...

...While I don't like the thought of a cellphone controlled blaster (unless it's like an autonomous turret), there have been a couple people who've asked me about integrating their blaster with an HUD for a Google Glass sort of device. What do you think about that sort of thing?...


I failed to explain the "mod" to the mags. I'm not sure you'd even call it a mod though. No cutting is needed, and it's entirely reversible. All you need to do is hot glue a magnet in one of the channels on the side of the mag. I've looked it over and checked it with every blaster I have access to, and it does not interfere with any of them. I thought about making a type of barcode sticker that could be read as the mag is inserted, but the reed switch system seemed much simpler and less expensive to me.

The display was inset on the first TR-27 because I mounted the components to a PCB prototype board and it didn't allow them to be mounted flush. On the second display I made. It can be flush mounted

Posted ImagePosted ImagePosted Image


Ultimately I want to use this OLED or one like it. It may lose a little of the cool factor because it doesn't shine blue on your face, but I'm interested in functionality.

Posted Image


I think the HUD via google glasses or similar would be amazing. If the device is compatible with bluetooth, I don't see why it couldn't be done.

I think the cellphone would be cool for a couple reasons. I'm a paintball player originally, and I enjoy setting a good ambush. Key to a good ambush is surprise; its a wonderful tool. If I could set my TR-27 in a hidden location, and I wait for the right moment, I could then remotely trigger the blaster to fire, and when they turn toward it, I pop up behind them and take them out with my sidearm.

Plus, it's a great prank tool if you loan your blaster to your friend to use.

Bee-Ri

Is there any way to increase the firing speed of the automatic mode without emptying
the magazine? For example a potentiometer or a PWM circuit to control the pusher speed.


If I understand your question right, you are wondering why in "Empty the Gun" mode, it has to run until it is empty.

There are a couple reasons for this. I take out some of the "safeties" in this mode so that it will fire as fast as the motors can run, so I doubt that the piston would stop in the ready position if you only fired a couple darts and then stop. In fact, if you watched the video, you'll notice that the display was blinking when it finished firing the 35 rounds. That was because the piston didn't stop where it was supposed to.


Both Bee-Ri & roboman

Also, do you plan on making the code available? It would be interesting to read the code
and possibly adapt it to work with something like a Nitron.

Would you mind posting your code or a link to Github or something? I'm interested to see how you did it.


Code code code... I'm really thinking about it guys. On the one hand, I love to help others and explain everything away. But on the other, I'm hoping to sell this, and hopefully pay for my Nerf/electrical hobby. If I can bring in enough income, I'll keep modding more blasters.

I'll let you guys know what I decide on. As an alternative, I might make an in-depth article about programming though.

Good news though, my H-Bridges came in today, so I'll be experimenting with them shortly! Thank you all for your compliments and input. Like I said, I think Nerf and I will have a bright and fun future together.

Edited by Technician Gimmick, 13 May 2014 - 11:48 PM.

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#12 Just582

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Posted 14 May 2014 - 12:50 AM

One question, a couple statements.

How much did this cost?

Sell this thing for ten times more than that on ebay. People will go apeshit over this. I wouldn't be surprised if someone killed you to get this. Words cannot say how great that monster is.
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Why are there so many Retards in this world?
Why can't we just enable the fifty percent plan?
Heck, why not the ninety percent plan?

#13 DORKSABER

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Posted 14 May 2014 - 02:53 PM

One question, a couple statements.

How much did this cost?

Sell this thing for ten times more than that on ebay. People will go apeshit over this. I wouldn't be surprised if someone killed you to get this. Words cannot say how great that monster is.


The parts for my version of the ammo counter and fire control comes out to about $30-$40, and that's not including the cost of software development, cost of labor, cost of the paintjob, cost of any other mods (like installing carbon brushes), and cost of the rapidstrike itself.
His ammo counter uses some parts that I don't use either, so his costs are probably closer to $60 to $80 only for the ammo counter and fire control.

If you are really serious about that markup, the turnkey product for this mod would probably be at least $500. I don't think anyone would pay for that.
The last commission I did of this sort of thing was for around $270, including the cost of the blaster and other mods like motor swap and minimization and paintjob, and even at that price I think it'd be really difficult to find buyers.

Edited by D4RK354B3R, 14 May 2014 - 02:56 PM.

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#14 Technician Gimmick

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Posted 15 May 2014 - 10:05 PM

One question, a couple statements.

How much did this cost?

Sell this thing for ten times more than that on ebay. People will go apeshit over this. I wouldn't be surprised if someone killed you to get this. Words cannot say how great that monster is.


Surprisingly, my hardware costs aren't too bad. While I doubt I could ever make enough out of this to pay for the labor and software development I've put into this, I figure I can offer a price that will make it reasonable for people. I am considering putting this blaster on eBay starting at $200. However I really really want to solve this "gibberish display" issue before I do.

On top of that, my wife and I are going to be helping out at a local Bible camp this summer, and it will probably take up most of my time. But if people are interested in owning one of these, send me a PM or something so I can at least contact you if/when I can offer a solid design.

Gotta go for now. Have fun everyone!

- Gimmick

PS it is more than just "ammo counter and fire control." the LiPo battery allows for increased dart speed, as well as firing rates. Edit: Oh yeah, and I've already had to fight off 3 ninjas for this blaster.

Edited by Technician Gimmick, 15 May 2014 - 11:05 PM.

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#15 roboman

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Posted 16 May 2014 - 04:54 PM

Wow, I'm glad you all liked it so much. It really has been a very fun project to work on.


roboman


The piston motor must have a motor brake in order to stop fast enough that you only fire 1 dart. I did some testing to see just how effective the brake was. I ran the motor at full speed for 1 revolution, and then let it coast. After that single revolution, it coasted 2 and a half more without power.

So far I have been using a micro relay to engage the motor brake, and a MOSFETT to control the speed of the motor. I'm going to experiment with an H-Bridge for two reasons. First, it has a built in braking system that unlike the micro relay, will not interfere with communications between the Arduino and the Max7219 LED controller. Second, I am considering using reverse to stop the motor even faster than the motor brake could. (Yes, I know this will put a lot of stress on the motor.)


Both Bee-Ri & roboman



Code code code... I'm really thinking about it guys. On the one hand, I love to help others and explain everything away. But on the other, I'm hoping to sell this, and hopefully pay for my Nerf/electrical hobby. If I can bring in enough income, I'll keep modding more blasters.

I'll let you guys know what I decide on. As an alternative, I might make an in-depth article about programming though.

Good news though, my H-Bridges came in today, so I'll be experimenting with them shortly! Thank you all for your compliments and input. Like I said, I think Nerf and I will have a bright and fun future together.


I guess that makes sense. I was planning on retaining the original piston reset switch so I don't have to worry about braking or anything, since it shorts the motor contacts and does the same thing that you're doing with an H-bridge. The reverse is an interesting idea, though it will be interesting to see how you wind up applying it during the firing cycle, because if it's wrong, it obviously just won't work right.

As for the code, I understand where you're coming from, but keep in mind that your code will only work on your setup unless someone manages to exactly copy what you did, and the people who are willing to put the time and effort into building one of these or even something similar generally aren't going to be interested in paying you to do it, so releasing your code just helps the community build cooler stuff and improve on what you did. Besides, you're gonna have competition from me in about a month or so in the form of drop-in modular kits, regardless of whether your code is public or not, since I don't even work in the same language that you used; I'm just interested in seeing what you did because I like reading through that kind of thing.
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#16 Technician Gimmick

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Posted 17 May 2014 - 09:56 AM

Okay, I've decided to include the code of you all to check out. I haven't the time to clean it up, so it's just a copy paste, so the tab info doesn't show. (makes the if statements hard to understand.)

Enjoy!

- Gimmick

Code


Edit: Now you can take a look at how I've reversed the plunger motor to get it to stop faster.

Edited by Technician Gimmick, 17 May 2014 - 10:12 AM.

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#17 Aldegar

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Posted 18 May 2014 - 07:56 AM

I don't know anything about electronics but would this thing work for a flywheel blaster? mosfet
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#18 Technician Gimmick

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Posted 19 May 2014 - 10:43 AM

I don't know anything about electronics but would this thing work for a flywheel blaster? mosfet


Not likely. I suspect that it monitors current flow to tell when the trigger is pulled. But on the rapidstrike, it has the flywheels running all the time, so the MOSFET wouldn't be able to tell when you are pulling the trigger.
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#19 Y-Brik

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Posted 19 May 2014 - 11:37 AM

This is fantastic, you're making my RS jealous for an upgrade!
A few observations/suggestions:
-Have you considered making the code interrupt-driven? It may be neater code, and save battery. Basically, instead of polling all the I/0 all the time, the arduino will "notice something has changed" and run the appropriate code.

-For user IO, I really like that OLED display, maybe integrated into the cheek rest if there isn't enough room where you have your ammo counter. I may be hitting the garage sale myself when the paycheck hits!

-If you go with the OLED display, consider a tactile 5-way switch for your input, accessible by the right index finger. Imagine tweaking firing control and other settings from there- and it's more discrete than the rocker switch. You may want to use your voltage divider trick there too, or give in and grab a shift register.

EDIT: More info on interrupts

Edited by Y-Brik, 20 May 2014 - 12:51 PM.

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As I said I have not not alot of testes yet but I will be once I finish the mod.

Why I am boycotting Hasbro

#20 Technician Gimmick

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Posted 19 May 2014 - 04:07 PM

This is fantastic, you're making my RS jealous for an upgrade!
A few observations/suggestions:
-Have you considered making the code interrupt-driven? It may be neater code, and save battery.

-For user IO, I really like that OLED display, maybe integrated into the cheek rest if there isn't enough room where you have your ammo counter. I may be hitting the garage sale myself when the paycheck hits!

-If you go with the OLED display, consider a tactile 5-way switch for your input, accessible by the right index finger. Imagine tweaking firing control and other settings from there- and it's more discrete than the rocker switch. You may want to use your voltage divider trick there too, or give in and grab a shift register.


I'll have to look into the "code interrupt", but I'm not entirely sure what you mean. The Arduino itself isn't using much power though, I'd say the IrLED and the 7-segment displays are using the most of it.

I like your switch, but since it's arduino controlled, I can take a regular push button, and make it cycle through the modes. I thought about using the warmup trigger for that purpose, but I decided on the toggle switch because you can instinctively operate it without needing to look at see what mode you are in/cycling through.

I'd love to find a nice 3 position rotary switch what I could mount in such a way you can operate it with your right thumb, like the M16.

Thanks for the suggestions! I love hearing new ideas.

- Gimmick
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#21 Y-Brik

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Posted 20 May 2014 - 12:56 PM

I'd love to find a nice 3 position rotary switch what I could mount in such a way you can operate it with your right thumb, like the M16.

Like this one?
Or this one?

Edited by Y-Brik, 20 May 2014 - 01:06 PM.

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As I said I have not not alot of testes yet but I will be once I finish the mod.

Why I am boycotting Hasbro

#22 Technician Gimmick

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Posted 20 May 2014 - 02:55 PM

Like this one?
Or this one?


Yeah, like that second one.
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#23 Fostis2

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Posted 25 June 2014 - 09:50 PM

this is a very nice design. I'd like to get in contact with you and talk about a commission job.
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#24 Technician Gimmick

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Posted 26 June 2014 - 11:49 AM

this is a very nice design. I'd like to get in contact with you and talk about a commission job.


Cool! I'll PM you.
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#25 Technician Gimmick

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Posted 07 September 2014 - 03:37 PM

I am continuing my work on this to add an OLED display. I have some code for those of you who were interested in it.

Video of my first test OLED Test

And here is my code.

OLED Code


Enjoy!!!
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