What's the point of making robots if you can't mount lasers to them?
I am not making robots and I don't have any deadly lasers lying around. I do however play airsoft and I thought it would be neat to have a remote triggered, automatically firing gun which could be set up and left waiting for unsuspecting bad guys to wander into its line of fire.
Somehow, I settled on the following basic setup:
Two units: a sensor/transmitter and a receiver/trigger. The sensor would be placed where it can detect people that should be fired upon and the trigger unit will be connected to the gun.
Communication will be wireless using nRF24L01+ units, the sensor will be a passive infrared motion sensor (like the ones turning on the lights in the garage), gun will be triggered by a power MOSFET and both the sensor unit and trigger unit will be controlled by an ATmega168.
An Arduino will be used in the prototyping phase for testing the various components but the I will probably move over til plain C (avr-lib) at some point.
This is how it is going to look (more or less):
Considerations (stuff I need to worry about):
- the airsoft guns are operating on pretty high currents (20-30A probably).
- the system should be extremely easy to set up and activate.
- the units should small enough to be carried around in a magazine pouch of a standard tactical vest or so.
Inconsiderations (stuff I don't need to worry about):
- cost: I'm not rich, mind you, but since I'm not making these in bulk I don't need to worry about finding the cheapest relays and RF units.
- in-the-field-configuration: originally I was planning on using a rotary encoder and a 7 segment display for programming parameters like firing time and re-arm delay, but I've decided to forego this and just reprogram the MCUs if I need to change anything. At least in the first version.
- tolerances: since I will only be using my own guns I don't need to worry about huge tolerances - I can design specifically for the equipment I have.
- RF unit pairing: since there won't be more than one set of RF units, I don't need to worry about conflicting channels or TX/RX addresses.