Burst mode mosfet using an Arduino

[@juder.3986]

The best guide i could ever found! Perfect for p90s with the trigger problems they are known for

[@QuestionMark43]

This is exactly what I was looking for! Thanks

[@AirsofttechDk]

You are welcome.. As you may have discovered I'm working on a much smaller version...

[@Doile911]

Sir, This was awesome! you made my day, and made me revive my old aksu! Thank you very much!

[@AirsofttechDk]

Thank you verry much. If you have any questions pleas just ask :-) And of cause like and share, the more likes and shares i get the more videos I can make :-)

[@elliflorou2129]

Hello there, you have done very nice job. Do you think that is it possible to have different firing modes by using an externel push button or something like that ,to change between firing modes ? for example it can be a burst of 3, another of 6 and another of 9 shots and then full auto ? Is it going to be hard to write a code for this application ? Have you thought to add a low voltage alarm ? thank you in advance

[@buwongapatuhmen6173]

Can you make single shot but binary?

[@selcukg2196]

Hi, i have a question. My upper gear on a ICS have two blue wires, but your gearbox have only one. How may I wire it with to wires? Should i put one of the wire to ground? Can you help me please? And you did it very well my friend. Thank you for this video.

[@MarkButQuestion]

Great video. Just wanted to say your gearbox is kinda loud, my dude. Had similar sounding gBox myself when pinion gear was pushing too far into the bevel gear. Had to shave off 1.5mm off the bottom of the motor cage in my case (V3 gBox).

[@AirsofttechDk]

Hearing a gearbox recorded with a phone don't do it any justice .... It's not loud when you hear it in real life ... I'm an airsoft Tech and has been working on well over 500 guns so I kinda know what I'm doing ... :-) ... But thank you for your response :-) And I'm glad to hear that my videos are apreciated ... ...

[@AirsofttechDk]

Also: Shaving the motor cage down to better fit a motor (That sit's to high) is not a good aproach ... A MUCH simpler and better way is to just push the pinion gear futher down the shaft ... This can be done for all O type pressfit pinions, an most (not all) D-Types ...

[@MarkButQuestion]

Yeah, it must have been the microphone, then. Spent whole weeks watching shimming tutorials and didn't realize which channel I was watching. Keep up the good work.

[@MarkButQuestion]

It's an o-type pinion. I tried removing the pinion/pushing it towards the motor but it wouldn't budge. Even when chilled and heated up. I know it's generally not a good approach to shave the motor cage, that's why I kept taking measurements every 0.1mm as I was shaving it. If I later get a smaller (normal sized) motor I can still push it further into the gearbox.

[@AirsofttechDk]

Yea that happens... Again thank you for the comment :-)

[@vborgnet]

Gearbox eléctrica?

[@uss717hamptonify]

Very nice work. I'm currently sourcing the parts to build the circuit. Got a question though. Would changing Max_ON_Time allow me to get Semi instead of auto? I'm trying to get a Semi/Auto gun as currently my gun is Safe/Auto only

[@AirsofttechDk]

Yes it will ... It's still not a real semi, because the piston may end up beeing partialy retracted and there fore there is a risk of double firing ... But the worst thing that can happen is that once in a while the gun will shoot 2 shots ... So Yes you can do semi auto conversion this way, but it's not perfect ....

[@matellanin16]

muchas gracias amigo. me has servido de gran ayuda. te lo agradezco mucho

[@AirsofttechDk]

Thank you for your kind comments 👍 We always try to make things that help you guys ... If you need help or have any questions please feel free to contact us. airsofttech.dk/EmailMe.cshtml

[@AirsofttechDk]

We don't currently have any Spanish speeking persons helping currently, but using Google translate I thing I understand 😎

[@sirhoschi]

Nice project! You use delay for burst, was it "try and error" to find out the 200 ms? And why aren't you using a micro-switch on "cut-off" to count rotation instead of using delay, so you can use also 11.1V Lipos. Do you habe a solution for precocking? btw, sorry for bad english.

[@AirsofttechDk]

Hello Sir. Thank you for the comments. The 200ms was partly trial and error and partly Math ;-) The gun this mosfet was made for shoots 16 rounds pr second. 1000 ms pr second devided by 16 rps is 62.5 ms per shot ... 3 shot should in therory take 187.5 ms... But because it takes a little more time for the first shot I hade to add around 10 ms => aproximatly 200 ms ... The video above is the second in a series of mosfet video's I have planned... The next video (will be uploaded in a week or 2. Remember to subscribe and click the bell for notifications).. In this series I will step by step show you all how I step by step make a more and more advanced mosfet.... So with time more and more features will be added... One of the features i will be adding is ofcause "Auto detection of ROF"... And there are many ways of dooing this. One way as you say is a cut off switch ... But there are other options as well :-) Precocking is one of the features that are a bit more demanding to make (A simple version can be made purely in code)... So i will probably be one of the later videos ... But it is one of the features I have on the todo list :-) So if you are interested in DIY mosfet creation subscribe and watch the videos :-) Remember to push the small bell icon after subscribing so that you will receive notifications when i upload new episodes ....

[@sirhoschi]

Thanks for response. Do you think about magnetic induction instead of micro-switch? Spring relaxation would be nice, too.

[@AirsofttechDk]

I have a coupe of different ways of dooing it... You will have to wait and see :-) But i can say that one of the simple ways of dooing it will be to messure how hard the motor is working ;-) Spring relaxation is one feature that I was not planing to implement, but because you are interested i will put it on the todo list as well ;-) So thanks for the feedback ...

[@rimantascalyj276]

Hey AirsoftTech.dk, are you powering it with 7.4 or 11.1v LIPO. I tried to make it with Chinese copy of Sparkfun Pro Micro board and it blew up when I used 11.1v LIPO to power it :D. I suspect that voltage regulators on Chinese knockoff boards are not sturdy enough for the purpose.

[@AirsofttechDk]

In the video I have a text box at time 1:06 that clearly states "The arduino can handle up to 12V on the VIN pin" ... That means that an 11.1v Lipo fully charged will be at "4.22x3 = 12.66" ... That is in theory MORE than the arduino nano's recommended input of 12v.... BUT: In the documentation it is clearly stated "The Arduino Nano can be powered via 6-20V unregulated external power supply (pin 30)" So YES it can handle a 11.1v lipo fully charged !!! So my design works perfectly with a 11.1v Lipo and also works with 7.4v Lipo! But in electronics you can't just replace one component with another if they don't have the same specifications! The "Sparkfun Pro Micro board" that you have tried to use has an input pin called "RAW" that has the same functionality as the "VIN" on the arduino. BUT the documentation on that board say "the applied voltage can be up to 12V" NOT 20v as the arduino nano can handle !!!! So 12.6v (11.1v lipo fully charged) is LESS than the maximum of an Arduino Nano 3.0 BUT MORE than the maximum of a SparksFun ProMicro .... So NO you can't just change the components without proper modifications !!! Conclution: If you want to change components you need to check ALL the specifications ...

[@AirsofttechDk]

Also remember: There are different versions of the SparksFun ProMini !!! There are a 3.3 version as well ... If you use the 3.3v version the input pins CAN'T handle the 5v on the input pins !!! Another issue with switching boards is the current draw on the pin's for the MOSFET etc... Other boards may not be capable of delivering enough current fast enough !!! ... So another conclusion: Don't change components if you are not capable of calculating the results. ... Or you may end up burning components instead of making cool stuff :-)

[@AirsofttechDk]

Question for you: Why is it that you want to use the SparksFun Pro Micro ??? Why don't you just get and arduino nano ???

[@rimantascalyj276]

I just got it cheap, but it was Chinese knockoff. I did not get it from manufacturer (in US) directly. But the biggest problem is with all other small arduino compatible boards stating 6-20V possible unregulated input voltage is that in fact their voltage controllers cannot handle that very well. If you look at ardruino.cc products e.g. you would see that voltage controllers on these are shall I say "beefier" and can handle higher unregulated voltages. I searched the web for examples of arduino micro being powered from 3S 11.1v lipo and found one post in some forum that it did work but the voltage controller was getting very hot and person eventually decided powering it with 7.4 2S LIPO instead. This is the reason I asked if you were using your project with 11.1 3S LIPO in order to find out if you experienced any heating issue of ardruino board.

[@AirsofttechDk]

The thing you need to keep in mind is current draw! Higher current draw on the arduino will result in more wasted power in the regulator. But when the only thing the code does is power a MOSFET (Voltage controled not current controled like a transistor) so the current draw is verry little .... That's why the design can savely be powered with a 11.1v lipo (If you use a genuine arduino nano!) ... But ofcause the most optimal way would be to use a 7.4v Lipo (Or adding a buck converter to knock down the voltage range ...)

[@AirsofttechDk]

Hi there. Dynamic Bacon and other's have been asking allot why I don't use what's called a "flyback diode" in my designs. This is because i just use mosfet's that can handle the reverse current generated by the free wheeling motor .... Almost all Power mosfet's has "Body diodes" inside of them that does exactly that !!!! en.wikipedia.org/wiki/Power_MOSFET#Body_diode So why add and extra when there's already one in there? (Theres just no reason) BUT remember to get a mosfet that can handle the higher voltages...

[@lulussediyanto7971]

can this 3 shoot burst reset to default burst?

[@AirsofttechDk]

I'm sorry that I have not shown how to add a switch to select between burst and full auto. If you go to this page: airsofttech.dk/Guides.cshtml?Page=BurstMosfet_Improvement There I have created a guide on how to add a switch so you can select between full auto and burst mode.

[@josephpetkoff1135]

hi is it possible to get a copy of that code you wrote

[@AirsofttechDk]

Yes of cause it is 👍 You can find it at my web site: airsofttech.dk/Guides.cshtml?Page=BurstModeMosfet

[@AirsofttechDk]

And if you have any questions please feel free to contact us using the contact form located here: airsofttech.dk/EmailMe.cshtml

[@lulussediyanto7971]

can i replace arduino nano with digispark for this mosfet?

[@AirsofttechDk]

Well yes ... that is an option ... I'm working on a mini version that are controlled by a MUCH smaller micro controller... But yes a digispark conroller will work just fine.... The code needs to be changed a bit, and the wiring is different but all the principles are the same :-)

[@charlescooper1219]

Is there any reason not to use a ridiculously small controller (e.g. www.coolcomponents.co.uk/en/trinket-mini-microcontroller-5v.html ?) That claims up to 16V in max.

[@AirsofttechDk]

I personaly don't know that board, but the short answor is: No. Go ahead, if it can run on 16V input it should be fine .... If you want to be safe I will be posting a "Shrink your mosfet project" later this year ...

[@WhoIsSam113H]

Make it have some certain modes 1/3/6/--

[@pikkuhurja5710]

What is the unnececary gray thig disturbing view

[@AirsofttechDk]

If any one has ideas or things they don't understand feel free to ask, or send us comments and ideas for projects.... Use this link to contact us directly: airsofttech.dk/EmailMe.cshtml

[@rimantascalyj276]

Can this be used instead of Nano? www.arduino.cc/en/Main/ArduinoBoardMicro Thanks

[@AirsofttechDk]

Yes. Almost all arduino boards can be used instead, but it require some changes. The pin's are located a bit different on the 2 boards. D5 pin and A0, VCC and GND pin's are not physicaly placed the same place on the Micro as they are on the Nano. But if you can accomidate for the different pinout, then: YES No problem.

[@AirsofttechDk]

Aditional note: If you google "Arduino nano pinout" and compare the results with a search for "Arduino micro pinout" then you can see that the pins are located differently ....

[@rimantascalyj276]

Thanks, I guess it will just involve slight change to the code. I am actually planning on using cloned arduino from ali or ebay called Pro Micro with same ATmega32U4 as original, but chinese board is smaller and has no components on the other side (put some dielectric tape and mosfet on other side directly). Also uses microusb instead of mini Hopefully it is also stable enough.

[@AirsofttechDk]

The china boards are kind of hit or miss... Some works perfect, no problems, others don't work at all.... One thing that you should remember is to get one with a GOOD usb to seaial converter! The boards with the CH340 and CH341 are VERRY prone to breaking. This is because of drivers issues. So I reccoment that you pay the 0.5-2$ extra for a board with another usb to serial converter.... FYI: I thing 30-40% of the CH340 boards I receive have broken or was broken when I received them. Only 5-10$ of the god ones has broken .... And NONE of the genuine types i have has had any problems .... So I reccoment at least getting one with a decent USB to serial chip...

[@AirsofttechDk]

Bonus info: If you doo get one with a CH34x watch some of the videos showing the problems and how to fix the driver issues before you plug it into your computer! ...

[@hallometbas]

Nice one! I was looking to do something similar and stumbled upon your design. Is there any reason you didn't use the interrupt service routine for detecting triggerpulls? With that you could time the cycle in single fire mode (for accurate/selectable) bursts. gammon.com.au/interrupts.

[@AirsofttechDk]

Hi. Using interrupts will give precisely the same result (Perhaps with pico seconds faster response) but it will require one to handle jitter on the input. Because the trigger contacts may trigger the interupt multriple times. This is usualy handled by adding capacitors to handle the problem. But that will increase the physical size of the unit. That's why i keep it simple.

[@hallometbas]

If the speed stays the same as you say, analogRead will also encounter this jitter. I'll try both methods this week and give you an update if you're interested. Hardware wise, I pretty much copied your design :D. However i allready have a mosfet installed so im using the balance lead of my lipo to power the arduino and simply cut the signal wire to my mosfet!

[@AirsofttechDk]

"analogRead" VS "Interupt"... YES: Both will ofcause have jitter on the input pins!... For interupt this is a problem because each change will trigger the interupt routine... When using analogRead you may read a wrong value, but next cycle the jitter should have stopped and the analogRead will sample the correct value... So because analogRead is a PULL design not a PUSH design the problems will be VERRY hard to notice... Where the Interupt style can end up beeing a mess to get working....

[@AirsofttechDk]

In short: Worst case with analogRead is that the trigger pull will not be picked up in the first loop cycle, resulting in a delayed trigger of 1 loop time (perhaps 1/4 ms). Worst case with interupts is that the interupt may trigger when you release the trigger, making the gun fire when the trigger is released .... So interupts is simply harder to get working consistently ... It can be done, but I don't thing anyone can feel the difference....

[@hallometbas]

It works. Like you said dealing with normal button jitter and also button jitter due to a voltage drop when shooting full auto was a pain in the ass. However it works now allowing me to accuratly time a single cycle and use that value for burstmode. This means its plug and play for most guns without guessing a burst time.