ESP8266 Boards under investigation.
This is just a list of boards we have been looking at for various projects.
This board combines an 18340 rechargeable battery holder with a D1 mini board. There is a charging circuit for the battery. For our needs though, we are concerned with the following points:
- The battery is connected via a transistor diode drop to the input of an ME6211 LDO circuit. The ME6211 has a dropout of 100mV. Assuming 300mV drop on the transistor there is basically no headroom on the battery (3.3V output + 300mV transistor drop + 100mV LDO drop = 3.7V = battery nominal charge voltage).
- The circuit above wastes all voltage above 3.3V as heat
- we would prefer to see a switcher circuit which allows the battery to run down to as low as 2V before shutting down.
D1 Mini Pro
No components on the rear side makes this an interesting board to use as a module in a larger board. We would have preferred to see castellated holes for easy soldering to a main board.
The ESP-01F is the smallest wifi board implementation we have seen. It uses the ESP8285 for build in flash memory instead of using an external spi flash. It measures only 10mm x 11mm.
Trying to decide what firmware to run on your ESP board? Take a look at our ESP8266 firmware comparison.