FriiTriga, a triggered controller with an optical beam shutter using a hard disk drive voice-coil actuator

Abstract

We present in this article the complete setup to build a triggered controller with a mechanical optical shutter. The system is a low cost, Do-It-Yourself, and easy to implement setup with three functionalities: Manual mode, direct mode with TTL signal command and Triggered mode with a TTL signal command. Our setup is primarily intended to be integrated in optical setup where one needs to control the opening time of a light path, but can be used also for any other setup where one wants to send a TTL signal to command another subsystem (in our case the shutter is that subsystem). The shutter used here is hard disk drive voice-coil actuator, which was already demonstrated to have interesting potentialities to be a mechanical shutter.

In the Manual mode, this setup achieves an opening and closing time of 3 ms. In Direct mode with TTL signal command, the setup has a delay response time of 19 ms and a minimum open pulse time of 23 ms. This low cost device which can be made with less than 50€, have similar characteristics with commercial ones which can be twenty times more expensive.