Electronic – arduino – How to create a permanent application from something prototyped with Arduino

To press a switch, you'll need some kind of expensive solenoid or servo, and mechanical linkages, and mounting hardware, and trigger pressure characterizations, and power-loss state characterization, and a 12V power supply, and driver circuitry, and it all adds up to a lot of work to push the physical trigger.

If I were you, though, and had access to the hardware, I'd characterize the circuit the trigger switch is attached to (is it normally open or normally closed is really all you need to know), and attach a simple relay or MOSFET to an I/O pin on a microcontroller (I'd suggest the relay, because it's closer to the original circuit, avoids any voltage referencing issues, and has a mechanical spring to ensure that if your circuit goes dead, the trigger won't go off). Then, remove the switch from the gun, and attach your circuit.

As far as microcontroller eval boards ready to use out of the gate, there is the arduino family of course. but also consider the msp430 launchpad for $4.30. good instruction set and similar in performance to the avr with a lean toward low power/cost. For $20 you can get the stm32f4 discovery (not to be confused with the stm32 value line discovery or stm8 family) which is generally less than you would pay for a usable arduino ($35-$50) but runs circles around the arduino 168Mhz, floating point unit, caches, etc. In the upper end of the arduino price range there is another arm the mbed (mbed.org), which is probably the closest to the arduino sandbox experience.

If you want to stay in a standbox and just make api calls the arduino is probably where you want to live, there is the mega for more performance or go with the leaflabs maple which is arm based but attempts to provide the arduino sandbox experience.

You can get a lot more performance, bang for your buck, etc if you take on a little more responsibility and knowledge about what is going on. I recommend all three platforms (avr, msp, arm/thumb) and multiple vendors (avr and msp are locked in but arm is sold by everyone with different peripherals and I/O). For example you may be used to a platform that has no pull ups on the gpio lines and have to use external components where another chip or vendor provides that on chip at a comparable price/performance point. Likewise you may like bit banging a serial port or spi bus but find that for the same money, power, size, etc some other vendor has hardware to assist in that interface.

if nothing else it is in your best interest as a programmer and someone wanting to get into hobby electronics to know more about what is going on outside the sandbox. As a way to get into this hobby electronics world the arduino is a very very comfortable transition from application programming on an operating system. sparkfun has some kits now that include the serial interface and a few periperhals there is a lilypad kit (an arduino platform) and maybe a pro kit, both are not the arduino shield form factor if that matters. sparkfun sells retail boxed and many other flavors of arduinos, the uno, etc. (the st and msp boards mentioned above you should start at ti or st's website or go to github.com/dwelch67 and I have links to the various boards in my examples).