Yeah i use an internal switch to sense insertion. Actually repurposed one of the existing lock switches.
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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:
If i make up a kit, including pre-loaded arduino, all components, switches, and a custom made PCB, would anyone be interested?
I am planning on duplicating your mod in my own rapidstrike within the next month or so. If you want/need a beta tester, your kit would save me a lot of time. I am extremely tech savy, and have a friend who is arduino experienced and a very good coder who is willing to help me with the project. I would be very interested in buying a kit from you, even if it's in an alpha or beta state.
If you want to add smartphone control, you can do it the easy way over bluetooth. If you add a bluetooth UART from Adafruit you can use their existing Android/IOS app to send data back and forth.
Love your build. Started doing the same thing to mine as well. Built mine on a single board like this:
But once installed so the displays are on the right side of the gun, i found it was slightly too thick and was interfering with the magazine.
So ive since made a far smaller version:
My magazine detection is using switches to detect the ridges on the sides of the magazines. With a couple of notches its quite simple.
If you're running out of pins on the pro mini, and dont want to use a larger arduino, you could always use an i2c multiplexer/extender to let you use more devices.
Very nice work there! What are you doing to control your motors? And have you had any communications issues from it? My main problem in times past has been communications between the arduino and the controller chip for the display.
Again, good work!
At the moment mine is just a counter and magazine detection. I havent yet done any motor or wiring upgrades, but that is on my list to do.
I hadnt considered using the arduino to run the motors at all, just didnt see the need. I was thinking about using a 1-2" OLED display for more info, ie: counter, inserted clip size, batt voltage, maybe motor RPM, but i'm specifically going for an Aliens pulse rifle look on this one.
I assume you're using a MAX7219? The very first one i used on my breadboarded circuit i did have some troubles. I had to almost power cycle it a bunch of times, try driving characters repeatedly before it would be stable. And then the next day, it would misbehave again. But the subsequent ones i tried didnt have that problem.
I also found I could get rid of the 2 recommended capacitors with no ill effects. But then i am using short and minimal wiring, so maybe less need.
My build here: http://nerfhaven.com...showtopic=26360
Instead, use a switch to detect when the firing plunger has fired, and then stop the motor. Don't need to time anything then, can just run the motor until the switch is pressed.
I'd also put a pull down resistor on the arduino pin driving the transistor. Otherwise when the arduino turns on, the voltage on that pin might briefly go high and run the motor.
Also, think about using a h-bridge instead of transistor. Can run it from a pwm arduino pin and control the speed more accurately.
Ahh it is a 360, thought so.
The plastic gears that do the retracting and gearing of the motor seem like they might not last if the motor gets sped up with a few extra volts, are there any upgrade gear sets etc available anywhere?
Or, could look at replacing the mechanism altogether with a stepper, or RC servo.
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.
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.
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:
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!
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.
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:
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:
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.
Source files here:
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!
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.
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?
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.
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?
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.
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.
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.
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.
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.
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.
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!
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.
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:
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.
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:
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.
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).
I was going to order a couple of airsoft scope accessories for the tacticool look, since they look better, and can be cheaper than the Nerf brand plastic parts.
But they obviously they're for "real" gun mounts such as picatinny and weaver rails. Are any of those directly compatible with Nerf rails?
I know I can buy picatinny rails in various lengths and bolt them on, but i'd rather not add extra parts if i can avoid it.
Just about there, I cant be bothered swapping the IR sensor, so just gotta write some code so it says MAX instead of dropping to zero.
On the plus side, these just arrived:
Works great. Havent used the SD card to load an image yet, but hooked it up for testing and its all good. Does need some extra double sided tape between the LCD and PCB though.
So I re-jigged the wiring, its now using the 4xAA's for just the arduino side of things. The motors are now powered by a 7.4V 4000mAh LiPo stuffed in the butt of the gun.
The displayed voltage is for the LiPo, and the RPM counter now works heaps better, though it has a bit of trouble keeping up at full RPM!
So all my issues solved, and a nice little performance boost as well
Pics and a video soon.
This is the circuit (i think), hall sensors for magazine size detection, one switch for magazine insertion detection, and other switch for trigger.
The IR LED/transistor for RPM counting are still connected in the Stryfe, and the code is still there, but i'm not displaying it on the screen until i can get a hold of an oscilloscope to work out why it drops out.
The OLED screen also needs a 3.3V source, and fortunately the nano has a regulated 3.3V output.