Build Instructions

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• 1

  Step 1

  Pick an ESP8266 version. The minimal requirement is one GPIO input, so any will work. I used a Nodemcu board (flashed with Arduino SDK and using Visual Micro for coding). The ESP12e/ESP13 dev boards and the Nodemcu board have a voltage regulator built in, but there are cheap AMS1117 power modules to use for the chip versions.

• 2

  Step 2

  The output jack for the trigger signal uses an open collector on the tip (blue wire in RatZapper). My first version used a PNP to pull a GPIO high. The second version just uses a 10K pullup (didn't try using just the internal pullup). So it is easy to use either a 2.5mm plug or tap off the jack terminal.

• 3

  Step 3

  I've been powering my two for several years with 5Ah 5-cell NiCD packs. One pack died last year so I'll be switching to 2S LIPO at some point. I'll probably add a 6V regulator to be safe. There may be some 3K+ mAh packs that will fit in the battery compartment. For now, I am trying an old 6V 2A wallwart. The RatZapper gives a green light with it and I could trigger it manually without total protonic reversal.

  There's room in the control box lid to add a DC power jack if desired. For one, I added a jack and made a Y-cable with JST connectors, one for power in (wallwart) and one for the ESP (input to a voltage regulator or VIn on Nodemcu). For the minimal version, I'm using 3-wire servo connectors, which gives power, ground, and signal to the ESP. For both, I just used the unswitched power wires.

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