WattIsIt Hardware

A battery watt meter using ADS1115 and a shunt to measure power usage. The Arduino sketch is located in Arduino/WattIsIt. Been using the DOIT ESP32 DEVKIT V1 board.

Version 1.2

KiCad Model PCB

Case & Battery Holder

Download all STLs for printing the hoder and case here

Hex Oval

Wiring Diagram

+ Positive battery terminal

- Negative battery terminal

L Low side of current shunt resistor

H High side of current shunt resistor

Bill of Materials

If using a BME280 on U3 can skip the AHT21 at U4. The BME280 has tempurature, humidity and pressure/altitude.

Item Link
U2 ESP32 https://a.co/d/ff7WulK
M1 ADS1115 https://a.co/d/gfCO6jt
U1 Voltage Reg https://a.co/d/2Gd8mMj
U4 AHT21 https://a.co/d/6xBWBLx
U3 BMP280 https://a.co/d/1HV9oyw
U3 BME280 https://a.co/d/eRQ7Lw4
J1 Terminals https://a.co/d/8nVocXb
J1 JST Connector https://a.co/d/0xq4sMO
Shunt https://a.co/d/2KoI4U9
R1 36k Ohm https://a.co/d/88x0EcR
R2 10k Ohm https://a.co/d/3lXzVxy
#10 Ring Terminal https://a.co/d/7aQ1Wun
M8 Ring Terminal https://a.co/d/6IeT5Sb
Conformal Coat https://a.co/d/5Z8R07R

Arduino Code

The Arduino sketch for the WattIsIt module is available in the Arduino/WattIsIt directory. This code handles: