Wow, yeah i'd never thought of using outrunners!

 

Impressive engineering work, but not quite my style. I like my blasters to appear minimally modified, the electronics should look like they're part of it, not quite so added on. But thats my personal preference. 

 

Now i'm off to look at outrunners

The last of my parts arrived today, will start installation tomorrow

Got it all assembled today and started debugging. For the most part everything is working fine.

 

Have 2 issues:

I had set it up to measure the current draw of the whole system, but have discovered that sensor is only good up to about a 3A limit. I'm pretty sure the stock motors will exceed that even on alkalines, certainly when i put in a LiPo. I think i can rework it to be good up to 30A though, but need some components from ebay to do it so thats disabled for the moment.

 

Secondly, i had set it up to measure the speed of the dart. Had 2 IR sensors, one at the entry to the flywheel cage, other close to the tip of the barrel, with about 11cm between them. But ive found because of the rate of fire, it only works if i fire a single dart. Firing more than one results in the second dart triggering sensor 1, just before, or at the same time as, the first dart exits the barrel. This was messing up the calculations, either getting 0 speed, negative speed, or stupid speeds like 50m/s.

I might be able to get it to work by moving the first sensor to the exit of the flywheel cage, but it will reduce the distance and time between sensors, so may mean the result is less accurate, but will give it a go..

Moved the IR sensor, but still a bust. They 2 sensors are just too close and the darts are moving too fast. 

At 5cm apart they register with zero millisecond difference. Would work on a longer barrel but at such a short distance theres just no difference in time to measure

Well the blaster is finished. All the counting, battery measuring, dart firing detection, mag size detection, single/triple/auto firing all working. Turns off the motors (via relay) when out of ammo to save battery, and all working properly.

 

And i dont like it

 

The electronics i've put in all work fine, the problem is the belt dart feeding mechanism, its too imprecise. What i mean is, if i have it in single or triple shot mode, the motors get turned off after a single round, or three rounds. Then get turned back on once I release the trigger ready for the next shot. That all works, but the position of the belt and the nubs that grab a dart are too unpredictable. It can push another dart in before it turns off, or it half pushes a dart that enters the flywheel cage but doesnt shoot, but then when i fire next, i get 2 rounds or similar. I just cant think of a way around it.

 

In a Rapidstrike or something with a more controllable pusher mechanism it'd work fine, but this hyperfire belt drive mechanism just doesnt lend itself to controllable firing.

I have a bunch of lipos in my parts box. Probably use a 2s 4000mAh 20C pack, had it spare for a while. At the moment the motors are stock so no real issue there. 

Havent decided whether i'll end up putting in some rhinos or go brushless.

 

Will run it all off the same motor, have a small 5V regulated power supply that i'll use to run the electronics. Wont draw much anyway.

Ayy!

You got the code for that?

I kinda undestand C.

 

-Montymarks

 

Not quite finished yet, still getting it how i want it, but its based on the version i used in my stampede, follow the link at the top to find that.

So far have changed the screen layout a bit, doesnt use the same motor drive and firing detection code though.

 

Will post the code once its done, but the Stampede version will show you most of it.

I'm using using millis to get the 4x/second calculation so when its working it will update the display 4x/second. Nothing to be gained by using micros.

 

I'm using an IR LED, which is matched to the IR transistor. (same manufacturer, same frequency etc). Too difficult to fit a laser diode in where I want it.

 

According to the datasheet for the transistor it has nice small trigger times as well, and even assuming a max speed of 30,000rpm, thats only 500/s, which both the transistor and microcontroller should be perfectly capable of handling. I made the hole in the flywheel longer so it has a greater period to detect the high of the LED per revolution, but that made no difference.

 

In theory, and by all the numbers, it SHOULD work! Thats why its so frustrating.

I'm going to go and buy a bunch of different IR transistors today from my local electronics shop, and try others. Maybe one will work.

The wiring has been upgraded and it will use a LiPo, but i havent yet replaced the motors.

 

I actually havent done anything on this in ages, have a new job and have been flat out. But yeah, some rather, umm, interesting ideas.

Yeah i considered the code as well, which is why i stripped it back to a test sketch that does nothing but count the interrupts.

I'm only bothering to count 1 motor since they have the same power supply and are subject to the same braking from darts etc.

 

The M0 controller runs at 48Mhz, so shouldnt have any dramas, even assuming a high rpm count.

 

 

Well the RPM counter is giving me grief. 

I'm using an IR LED/transistor pair attached to either side of a small hole in a flywheel, and at low RPM it does work, but as soon as it gets up to full speed it stops counting. I thought using a faster micro controller would solve it but no change.

 

I can think of 2 reasons why:

1: The output on the IR transistor cant change state fast enough to keep up with the pulses its getting.

2: At full speed the time that IR light is let through the hole in the flywheel is too small for the transistor to register it. 

 

I have some different IR transistors i'll test to see if any of them work better to solve option 1.

 

Only solution to option 2 i can think of is to elongate the hole in the flywheel so the IR light gets longer per RPM to register.

But i dont want to unbalance the flywheel  by removing too much plastic.

 

Anyone have any other suggestions?

Installation update. 

Have installed most things on the left of the shell. The connector you see on the right is so it can plug into the other side of the blaster. Makes it easier when being assembled/disassembled all the time.

On this side are the mag size sensors, LCD screen, joystick, button, mag insertion switch, buzzer, and micro controller.

 

 

The outside. 

Bit hard to make out, but the white overlay lines up with panel lines on the shell so it looks at least sort of part of it. The large round black bit is the joystick, and little black button above it.

OK so i had some wiring issues with how it was installed, was having nightmares with the screen, and getting the IR/RPM sensors working, so i ripped the whole thing apart and re-assembled it properly. Much neater now and no issues.

 

On the left side of the shell there is the 1.8" screen, joystick, reset button, mag insertion switch, mag size sensors, buzzer, level converter, and of course the arduino.

On the right side, are relay, voltage sensor, dart IR sensor, RPM IR sensor, and power supply. For now its running off standard alkalines, but have replaced all the wiring so it will be getting a LiPo shortly.

 

The code is about 85% done. At the moment its tweaking things like checking the mag size sensors are set to select properly, make sure all the magazine insertion stuff is in the right order, and that the screen updates properly when things happen. All the code is there, mostly just the order things happen.

 

There are 2 IR sensors in the barrel, one at the dart insertion point, one at the exit. By measuring the time it takes to get between them, it should give an approximate dart velocity. However when only measured across 10cm, it may not be wholly accurate, but it looks cool

The RPM sensor is also working properly now. On alkalines with stock motors it gets around 11-12k rpm. However i'm measuring every 250ms and multiplying it out, so again its not 100% accurate, but pretty close.

 

The gear going in the left side:

 

 

And the right side installed. The flywheel enclosure and flywheel got a quick spray of black paint to minimise any IR reflections.

Its a great setup for flinging darts in rapid succession, i'll give Hasbro that. But not for control.

Got bored waiting for my parts to show up from ebay, so picked up a sensor and magnet from the electronics shop to test with. $7.75 for one sensor locally, or $2 for ten from china!
With a neodymium magnet, the sensor can detect it from at least 15-16mm away! So wont have any issues with wobbling magazines causing misreadings.

Also when coding the arduino, i worked out that i can get more values by using a magnet that a switch. Two switches gives me four readings:
off/off
on/off
off/on
on/on.

But because of how the hall effect sensor works, i can detect no magnet, or north or south polarity. Which with two sensors gives me nine combinations:
none/none
none/N
none/S
N/none
N/N
N/S
S/none
S/N
S/S

At the moment I only have 18, 12, and 6 shot magazines, so really i can get away with using a single sensor and magnet, and just code those 3 sizes. Or lose the 6 and replace with a 25 or 35. And the 18's will be set to none/none, so dont need to mess about with them, and will only use a single magnet on each of my remaining 12's and 6's.

So I finally had some time to sit down and swap the switches out for hall effect sensors. Works a treat! Put them in the Rapidstrike and Stryfe, configured the same so the magazines detect the same in either blaster.

I also swapped out the switch i was using for the trigger counter in the Rapidstrike. It was detecting the movement of the pusher arm but i found if the blaster was held at an angle, the lever on the switch would jam against the pusher arm. So i swapped that out for a hall effect sensor too.

 

This is the insides of the Stryfe, you can see the hall sensors on the left half of the shell, connected to a 4 pin socket, which mates with a 4pin plug on the other half. Makes assembly/disassembly easy. And all works fine. They're on a piece of white styrene glued in to put them at the right distance from the mag.

 

 

 

And heres a short youtube clip showing the detection in action. Theres a slight delay of a second or two after insertion because putting the mag in turns on the Arduino, which has to boot.

 

https://www.youtube....h?v=DUmSJL-isHE

Ok, just a momentary switch. Did you happen to have a wiring diagram for the entire thing? I don't think I saw one on the front page.

 

Theres a full circuit diagram in post #14:

http://nerfhaven.com...ke/#entry349981

 

Also in the first post as an update/link.

What about magnetic switches instead of levers or pushbuttons? Glue a magnet onto the clip in the appropriate position. That would reduce the moving parts issue that may develop from repeated lever switch use - though i don't know how rugged magnetic switches are...

Very impressive work btw.

Actually i was sitting test fitting, and umming and ahhing about how to mount things, and magnetic was starting to appeal to me as well. Not necessarily because of moving parts failing, just that it would be less intrusive, and less of an issue if the magazine wobbles.

So i jumped on ebay last night and ordered some little magnets, and some hall effect sensors. Good thing is that by using them, i can move the connections on the arduino to analog pins instead, and free up a couple of digital pins for something else. Be 2-3 weeks before the parts show up though. But since i got 10 sensors for $2 with free delivery from china, versus $8 each locally, i'm happy to wait!

All installed. You can see a little black 4 pin socket in the bottom right, mates up directly with a male plug on the other half of the shell, makes it easier taking it apart all the time. Also trimmed the rails the jam door rides in so it opens all the way now.



Installed the switches to detect the magazine, running to the connector to the other half of the shell. I used pushbuttons, but i'm not happy with them, the actual button piece wobbles too much, and can be pushed aside instead of pressing in. So i think i'll replace both with lever type microswitches.

Great job, it seems very simple and efficient (in terms of functionality and cost).

This arduino is 5V logic, correct? Are you just powering the whole blaster (including motors and the arduino) off of alkalines, then?

Its one of the things i love about arduino's can use a simple tiny little board, and do so much with it. All the smarts around sensing the trigger, working the counter, detecting magazines etc can be done in software, without the need for loads of additional electronics. As it is, the pro micro has 14 digital IO pins, and i'm only using 6! Could easily add more features to it.

And yes it is a 5V version, but another handy feature of the arduino is an onboard 5V regulator. It can happily run off up to 12V, so a 3 cell lipo setup at 11.1V would be no problem. And with the addition of a $1-2 external regulator, could handle up to 25V! And yes at the moment it is just running off alkalines, I havent yet done any voltage mods to the motors, or replaced the wiring. Thats the next stage.

Expected BS noob post. Got awesome working counter. Was not disappointed.

Where do you go for resources on this stuff? I have an arduino but coding isn't my specialty.

Heh, thanks. I have an electronics and software background, so its quite simple for me. The official www.arduino.cc webpage is a great resource, but it helps if you know what you're looking for there. Another great resource is www.adafruit.com which sell parts, but have a great learning resource section. Check out https://learn.adafru...getting-started for the first of their arduino lessons.

Very cool but remove the locks in the blaster. They only make operation less smooth, and especially the dart lock can be a real pain which could cause problems with the counter if you get a jam.

TLDR; Remove locks to improve operation.

I have removed some of the locks in the Stryfe and RS, but not all yet. At the moment my aim is to get the counter installed and working, then i'll look at going through and doing voltage mods, re-wiring, and remaining lock removal. The RS once painted and modded to have the Aliens pulse rifle look will probably be more a show piece than play gun anyway.



Ive been test fitting the bigger counter in the RS. Removed the orange wire cover in the middle, was taking up too much space. I'm re-using the switch that was one of the electronic locks to detect a magazine is inserted, to turn the counter on instead. (the bottom left). The plastic lever isnt inserted at the moment, keeps falling out when i move the gun, same for the magazine release lever. You can also see a small 4 pin connector just to the right of it, that will go to the magazine detection switches on the left shell of the gun. A connector will make it easier to disassemble/reassemble. I was going to use a little micro switch behind the trigger to detect firing, but then remembered the RS is full auto, so that wont work. Instead the switch now sits in front of, and to the right of the pusher arm, and gets pressed whenever it extends to push a dart. It does safely clear the magazine there.


I have however found that the counter is thicker than i had planned on. As a result some of the pins actually rub against the magazine, and push it a little off centre. When the gun is closed up the mag will be straight, but will probably bend the pins it touches. They do scratch the top of the mag. So since the parts are cheap enough, and i have the design working fine, i'm going to make another counter for the RS, but compact it down like the one in the Stryfe. Will sit in the same place, but take up less room and wont interfere with the magazine.


So watch this space.

Btw, happy to provide a circuit diagram/parts list/arduino code if anyone wants them.

I had thought about using that switch.
I spent a while dismantling the trigger assembly etc and seeing what pushed what, locked against what, etc. And i technically could use it.

Good thing about the arduino is that i can set the code to look for a high or low, open or closed circuit so its possible. But, since i haven't yet done any power upgrades to the switches, wiring and motors, i decided to use a seperate switch in case that switch doesnt end up staying once i do the upgrades. If that makes sense?

And, yes, circuit diagram/parts list/arduino code would be most welcome when you get a chance.

Voila. It really is absurdly simple really.

Theres still 8 unused digital pins on the Pro Mini, so still plenty of scope for expansion, and i didnt use the analog inputs at all. Though i'm thinking of adding a light sensitive resistor which will automatically adjust the brightness of the display for day or night use to one of the analog inputs. The pro mini does need a USB to TTL cable to program it since it has no onboard usb controller. But, theres no reason the pro mini couldnt be swapped for an Arduino Nano or equivalent.

The MAX7219 LED driver can actually drive 8 digits, so other things could be displayed. Mighty handy that it fits under the pro mini! I even managed to squeeze the brightness resistor underneath between the MAX and the arduino pins.

I built my prototype without the 2 recommended capacitors, and had no issues, so the version i've installed doesn't have them. I've yet to have any issues without them so can save $0.50 if you want to skip them!

The pin numbers i chose for the 3 switches, and for connection to the MAX are based on the physical layout of the pro mini and were convenient to group. Can really use any pins, as long as they're defined correctly in the software.

Wow dude, have you considered a different type of display or even doing a "camera" sight which would route a small camera in front to a display in the back? Kinda like that nerf gun with the camera but minus the recording option...

 

This one was specifically going for the counter look from Aliends for a RapidStrike, but I'm currently playing with a couple of small OLED displays. One is a blue monochrome 128x64 dot display thats about 1" wide, another thats an awesome red but about 2.5" wide and doesnt really fit most Nerf guns, and a small 1.3" full colour OLED.

 

Looking at things like displaying batt voltage/maybe current draw, mag size, rounds used, possibly motor RPM etc. Also add a switch for single/rapid fire and have that mode displayed. Could also add a purely fun switch/display to select ammo type such as Normal, Armour Piercing, Tracer, Explosive etc

Plus when the rounds reach zero it can flash "Reload" or something.

 

Am looking at fitting one to a Stampede or a Rayven once i work it out properly.

 

I did even consider adding a range finder, and have the range displayed, but the cheapest suitable components i can find are about $100. Dont want to spend that much.

Here is an updated circuit diagram. The 2 parts circled in red are mutually exclusive, its one or the other. Can use a switch, or hall sensor for the trigger depending on the gun.

 

Source files here:

Rapidstrike: https://drive.google...iew?usp=sharing

Stryfe: https://drive.google...iew?usp=sharing

 

They're pretty much the same, but the Stryfe version is setup for a switch for the trigger counter. The Rapidstrike version is set to use a hall effect sensor and magnet for the counter. Both have the code for each, but commented out the non relevant part. You'll see when you look. They'll work in any gun, i just differentiate them by how the trigger counter is activated.

 

Its pretty well commented so you should be able to work out whats what, where to change pin assignments, timings etc. 

Its currently only setup for a 6, 12, or 18 magazine. But you can easily add 25 and 36 detection. 

 

Its also sensitive to the direction of the magnets (north or south) so test before gluing any in place.

 

You'll also need the LEDControl.h library from here: https://github.com/w...ontrol/releases

If you dont know how to install a library, info here: https://www.arduino....Guide/Libraries

 

 

Any questions, happy to answer, and any suggestions, happy to hear!

What kinda trigger switch did you utilize for the stryfe trigger counter?

 

Just a micro lever switch, some pics on the first page.

 

Without wanting to sound insulting, if i still need to provide an Arduino, a power source, a counting mechanism, and trigger mechanism to make your counter work, then what does your counter actually do?

Occurred to me i never posted a pic of what my Rapidstrike ended up like. I ended up adding nerf sights, and made a suppressor out of some pvc pipe from a hardware store. 

Put a 9 LED flashlight on the right hand side, which just has a rear mounted pushbutton switch.

Put a laser on the left hand side, which has a momentary switch on the grip in just the right spot for the thumb. (Its the red dot behind the motor switch).

 

 

Edit/Update 1: current circuit diagram here http://members.iinet...rf/circuit2.jpg

Please read this post about the 2 bits circled in red, they're optional: http://nerfhaven.com...trike/?p=349981

 

Edit/Update 2: Arduino sketches can be downloaded here:

Rapidstrike: https://drive.google...iew?usp=sharing

Stryfe: https://drive.google...iew?usp=sharing

Read this post for details: http://nerfhaven.com...e-2#entry351112

 

 

 

 

Hi all, a noob here.

After recently getting hold of a Rapidstrike, i decided i'd add a shot counter, in preperation for a repaint to look vaguely like an Aliens assault rifle. Figured while i was at it i'd make 2 and add one to my Stryfe as well!
I'm good with electronics, and decided an arduino would be the way to go, ordered everything on ebay and finally put it together over the last few days.

Breadboarded it first, used an Arduino pro mini since theyre small and cheap, added a 7 segment driver, couple of discrete components and the displays and voila! There are 4 switches on the breadboard, the 2 lever switches are for power, and triggering. The idea of the power one is it will only turn the circuit on when a magazine is inserted. And 2 small pushbuttons which will be used for magazine size detection. More on that in a bit.


Since theres loads of room in a Rapidstrike to the right of the magazine, i wired it all up on a single board that fits nicely. The leads are long but will shorten them when i actually install it. This has red digits.


I wire wrapped the back instead of soldering, far simpler when prototyping.


But that whole board is too big for a Stryfe, so i made a smaller version with the displays seperated. The little red/black wires you see disconnected go to the trigger switch and will be soldered at installation time. This has blue digits.


To save space, after soldering in headers to the Arduino to use for wire wrapping, i use double sided tape to stick the 7 segment drive underneath the arduino. Makes it nice and compact.



Decided to install in the Stryfe first, so cut out a hole for the displays and glued in the trigger microswitch. You can see here how the trigger mechanism presses against it.



I left the jam door switch connected, but bypassed the magazine insertion switch, and instead wired that up to turn the arduino on whenever a magazine is inserted. Wont drain battery that way, and acts to reset the counter when a mag is inserted.
Theres a space in the top of the gun above where i installed the trigger switch which is perfect for the arduino board, and obviously i sized the length of the cables to reach where the display sits. The display isnt fixed in place yet, just sitting there in the pic.


All assembled. The lighting makes the displays look superbright, but they're not, the brightness is controlled by the arduino and is actually turned right down. Just a camera lighting trick making them look super bright.



At the moment the Stryfe counter doesnt have magazine size detection, since i was going to try and make the placement of the switches the same in the Rapidstrike and Stryfe so i dont need to do much to the mags. Where i planned to put them in the Rapidstrike at the front of the mag wont work in the Stryfe. But i have now worked out how to do it, they'll be mounted on the left side of the gun near the top of the magazine.
Basically, all the magazines have molded ridges on them, like this:


So i'll just add a couple of notches to those ridges (where circled) to encode the magazine size. With 2 switches, i can set 4 sizes.
ie:
Pressed/Pressed = 18
Pressed/Not Pressed = 12
Not Pressed/Pressed = 6
Not Pressed/Not Pressed = 35 drum

And its just a matter of adding a notch (or not) on the appropriate ridge. Pressed means there is no notch and the ridge presses the switch. That way i dont need to do anything to my mags which are mostly 18's. And the 12 and 6's i have each only need 1 notch on the correct ridge, so minimal effort. The only one left out is a 25 drum, but that could be done by adding another switch. The arduino can do it, i just havent bothered since i dont have a 25 drum.


Not including wire/tools/time, the common parts cost (in US$) was:
Arduino Pro Mini with headers $2.92 each
7 segment driver $0.54 each
7 segment displays $0.79 each
Lever microswitch $0.65 each
Tactile switches $0.10 each

The larger one also has:
PCB $0.30
Wirewrap IC sockets $0.95 each, used 4
10k resistor $0.24 each
10uf 16V electrolytic capacitor $0.30
100n ceramic capacitor $0.32
(the 2 capacitors arent strictly necessary)

So total cost for the big one: $10.85
Small one: $6.13
Plus a few hours assembling and coding.

Hi Kingbob

Thanks for sharing this information with the nerf community.

 

No worries.

 

Heres a peek at my next one

 

http://www.youtube.c...h?v=Xj6GkkIPjXw

The 2 hall effect sensors i used are capable of detecting 9 different magazine sizes between them (and only using 2 inputs in the arduino). Thats more than enough for all the nerf magazines: 6, 12, 18, and 18, 25, 36 drums. But yes could add a 4 bank dip switch accessible from outside somewhere. But the magnets i used were like $3 for 50 on ebay, and only takes a few seconds to add one to a clip.

 

Btw if anyone wants the Arduino code for the circuit above, happy to share.

Sonofa... just put my Rapidstrike back together after a paintjob, and looks like ive lost or thrown away the little white plastic piece that pushes the switch at the front of the magazine, which is normally used as a lock, but i re-purposed to turn on the arduino! Probably threw it out thinking it was a part i didnt need! Suppose i better grab some styrene and look at making a replacement!

 

Interesting, how are you getting the motor rpm?

You could run brushless motors if you get a couple of small brushless controllers, and run the servo input on them from the Arduino.

You're right in that the 3 resistors on the buttons aren't really necessary. The ATMEGA328 has internal pullup resistors, so when you set the pinmode in software, if you set it as pinMode(pin#, INPUT_PULLUP) to use the internal pullup instead. 

 

Save a few cents! lol

Counting up is far simpler because it doesnt require knowing the size of the magazine to set the initial value.

 

Of course then its a matter of stopping it counting at the right value. Otherwise if you keep pulling the trigger it'd keep counting.

 

The 7 segment displays i used are about 18mm high from memory, they're the smallest i could find.

I've been asked by a few people if i'd make them one of my 7 segment style ammo counters like i used in my Stryfe and Rapidstrike:

http://nerfhaven.com...nd-rapidstrike/

 

If i make up a kit, including pre-loaded arduino, all components, switches, and a custom made PCB, would anyone be interested?

 

 

Assembled would be easy to do.

Measured them, they're 9.5x13mm.

Heres 2 on the back of my Rayven.

Hmm, I wonder how small an OLED i can find... i know some are 0.96", might fit