A helicopter carousel is a cylindrical apparatus that hangs beneath a helicopter and holds from eight to sixteen bags of seismic supplies. The bags contain equipment that is dropped to crews on the ground. The bags hang on hooks which are connected to solenoids. When a solenoid is energized, it releases a bag allowing it to drop to the ground.
The controller that Trinity Electronics designed sits in the center of the carousel and connects to the solenoids. The challenge was to replace an electromechanical unit that received only a ground, reset and 24 VDC trigger pulse. There was no continuous DC supply so this unit has to power up, read memory to determine the current step, increment and store the step number, release the next hook and then prepare to power down. It had to perform this function in all kinds of weather, in arctic temperatures and be immune to high electrostatic charges.
This product was custom designed for Canadian Helicopters Ltd.