Wednesday, February 9, 2011

TOZ-35 free pistol with electromechanical trigger

New project: electromechanical trigger for TOZ-35 free pistol.
Our goals:
  • Get rid of many tiny parts of mechanical trigger no more available today on the market;
  • Learn – how electromechanical trigger might work;
  • Original pistol weight and balance must remain the same as before;
  • Learn something new.
Electromechanical trigger consists of two main parts:
  • Electronic part. Subdivided into:
    • Power supply (rechargeable via USB);
    • Contact key (button, switch, pressure gauge etc);
    • Analog amplifier;
    • Digital converter;
    • Digital analyzer;
    • Impulse generator;
    • Solenoid.
  • Mechanical part – original bolt «as is».
Developers: me and Alexander Exl.

Sun, 13 Feb 2011:
We worked all day on strain gauge, Wheatstone Bridge and Instrumentation amplifier. Seems to be work. Photos a little bit later.
As you may notice – we use strain gauge – no buttons, no springs, no contacts, no trigger movement. Later it must be enough to tune tiny potentiometer to adjust the «trigger weight».

Wed, 23 Feb 2011:
Amplifier with the gain of 10000 in action.

Sat, 26 Feb 2011:
Noise immune threshold circuit has only two states - low and high.

Sun, 6 March 2011:
Trigger hysteresis switching and pull force measured in Volts.


  1. Anonymous10/2/11 00:25

    I want to buy one of this when the pistol is ready.

  2. I was planning to do a similar mod to mine... will you be posting more info on your project? I'm interested in more details on solenoid and the driver circuit.

  3. I will describe abstract our steps later.