When the circuit is done, and the code has been uploaded, the blaster is ready for operation. This is how it works.
In order for the blaster to function, a magazine must be loaded into the blaster. This will activate the power switch so that the Trinket can power up. You will know it is on when the NeoPixels start flashing the rainbow pattern.
When power is first applied to the blaster, the speed is set to zero. So, there will be no whirring of the accelerator motors. Press (and hold) the lower trigger to engage the accelerator at 50%. Press (and hold) again to increase to 75%. Press (and hold) again to increase to full power.
When you release the lower trigger, the accelerator will stop. This saves batteries, and makes the gun silent for when you are trying to sneak up on someone. (well, someone who can't see the blinky lights anyway.)
There is a dart sensor at the top of the trigger assembly that will detect the presence of a dart in the magazine. If there is no dart, the loader will not advance it to the firing engine.
Once a dart is detected at the top of the magazine, the trigger switch will activate the loader mechanism, which pushes the dart forward to the accelerator (firing engine.) The faster the speed of the accelerator, the more velocity applied to the dart, and the farther it flies (or the more it hurts.)
When you are out of darts, the trigger simply makes the NeoPixels flash.
Have a great time building this Nerf blaster! Use this guide as a starting point, then customize it and make it your own!!