Various breadboard-friendly boards based on ESP8266 or other chips are available on the market, but some readers are not quite satisfied with the offerings, and need more available pins on the breadboard so they ended up hacking the board matching their needs by either bending header pins, or soldering modules to stripboards. As I browsed new arrivals on ICstation website, I found a tiny board with ESP8266 module that exposes I/Os via what looks like 2.54 mm pitch header that should fit right into a breadboard.
But after further checking only three I/Os are exposed, and the board is actually specifically designed for wireless switches, and comes with firmware that works with eWelink app used in Sonoff devices. So the module could be useful for people wanting to control devices without doing programming at all, and limited to no soldering. Just connect the module, and control it without smartphone.
- PSA-B ESP8266 module supporting 802.11 n/g/n WiFi
- Ceramic antenna
- 6-pin header with 5V, 2x GND, OUT pin, LED pin, and key input pin.
- Misc – Status LED , matching button
- Dimensions – 2.7 x 2.5 x 0.8 mm
The boards looks very convenient if you plan to use eWelink app, but the UART pins are not directly exposed. However, Tinkerman also found PSA-B module inside ITEAD Studio 1-Ch self-locking board, and located Tx, Rx, and GND pins on the top side of the board, managed to upgrade the firmware to ESPurna using a cable with 3 pogo pins. For reference, PSA-B module is sold for $3.00 on ITEAD Studio, so total price for the board above could be a little lower than the $6.23 currently offered on ICstation, but at least it may save you time.