This is just a simple programming jig for the ESP-12 module.
When putting this device together, use <=40-mil pogo pins for the ESP pins. You can then place this device on top of a ESP-12 unit to access it's serial port. (Be careful not to short any of the pogo pins on the metal can though. It can be tricky!)
P1
is normal FTDI header. 5V should work.SW1
is a reset switch. Hold it down for >5s to bringGPIO0
low and release to start flash mode.D5
should light up whenGPIO0
is low.D3
is a power indicator.D2
should light up when the ESP is receiving serial data.
Check the schematic for the parts list.