Wemos D1 board, a $9 ESP8266 board in Arduino UNO form factor, now has a little brother with Wemos D1 mini. The board looks somewhat similar to NodeMCU with breadboard friendly I/Os on the sides and a micro USB port for power and programming, but what could make it more interesting, beside the $4 price tag, is that the company also developed several shields (aka add-on boards).
Wemos D1 mini specifications:
- WiFi 802.11 b/g/n module based on ESP8266EX with 4MB flash
- Expansion – Through holes with
- 11x digital input/output pins (3.3V) supporting interrupt/PWM/I2C/one-wire (except D0)
- 1x analog input (3.3V max input)
- Reset and power signals (5V, 3.3V, GND)
- USB – micro USB port
- Misc – Reset button
- Power – 5V via micro USB or 5V pin
- Dimensions – 34.2 x 25.6 mm
- Weight – 10 grams
The board is said to be compatible with Arduino IDE and NodeMCU firmware. ESP8266 analog input only support 1 volts, but the board support 3.3V because a resistor voltage divider is included in the circuit. Schematics are always a good thing to have, as well as decent documentation.
The company also designed 5 shields adding temperature and humidity sensors with either DHT11 or DHT22 (wider range and more precise), a user button, a relay (3A or 5A @ 250V, 10A @ 125V), or a microSD. A third party shield has also been designed for prototyping.
You can order Wemos D1 for $4, and the shields for between $0.99 and $4.90 on Wemos Aliexpress store. All these prices include shipping, how amazing is that? You can also find it on eBay for about $6. By the way, the latest revision (R2) of Wemos D1 Arduino UNO compatible board now sells for $6.50 shipped. 🙂
Thanks to Zoobab for the tip.