Zappy Module

From Hackstrich
Revision as of 05:28, 8 March 2015 by SarahEmm (talk | contribs)

Zappy Module is a board-level module that takes control input via some kind of protocol and outputs signals to zap someone like shock collars do.

Project Status

  • 2015-03-07: Started putting schematic and BOM together.
  • 2015-02-02: Started putting together overall circuit idea.
  • 2015-02-01: SPICEd out some ideas.
  • 2015-01-29: Captured waveforms of all output levels.
  • 2015-01-05: Arranged to borrow a shock collar to characterize the output of it.
  • 2013-05: Started throwing ideas around.

Overview

  • Control input options could be:
    • GPIO-based, simple "zap now" input (or a couple separate inputs that you can set with different options)
    • I2C/SPI/RS232
      • Could be used for instant control or programming levels/durations for later GPIO-based activation

Theory of Operation

  • Input voltage from 3-9V is stepped up to 10V using a boost converter (AZ34063U) to get the intermediary voltage rail
    • Or if 12V input is required, maybe use 14V or something as the intermediary voltage rail?
  • MCU controls a FET that charges a cap from that rail via a series resistor to control charge rate
    • Divider on the cap feeds into an analog pin on the MCU, once the analog pin reaches the desired level the MCU shuts the FET off again
  • Once cap is charged, MCU pulses a FET that dumps the charge on the cap through a 1:100 (or so) transformer and to the output
    • 0.1-1kV should be achievable via timing the charge FET
  • May need a dump resistor if the cap is charged and needs to be discharged without zapping?
    • Could use the series charging resistor w/ a different FET to dump the cap through it?

Collar Reversing Waveforms

  • All collar output waveforms are through a 1/3 divider, so multiply by 3 to get actual amplitude
  • Lowest level (1L) seems to be ~90Vpp, highest seems to be ~450Vpp
    • I thought the highest was ~2x that? Need to measure the higher ones again to double check