The MIT License (MIT)
A circuit to show voltage and current on a TFT display. Parts can be added using a small array of mounting holes on the board, plus two daughter boards can be plugged into female connectors. There is an on board 5V to 3.3V regulator which powers all components.
KiCAD files of the schematic and PCB.
- J1 - J8 are JST 1.5mm 3-pin connectors and are for the analog inputs or outputs of the 74HC4051 (8-Channel Analog Multiplexer/Demultiplexer).
- J9 is a screw terminal block for the circuits supply voltage.
- J10 is the Power Jumper. It allows the use of 5V on J9 or routes the V-IN on J9 to a daughter board which can convert the voltage on J9 to 5V.
- J11 is a 4 pin standard female socket for the optional Daughter Board 1. This board can be used for external circuitry to convert any voltage to the 5 volts needed by the 3.3V regulator.
- J12 is a 12 pin standard female socket that provides the 2nd daughter board with all the control pins from the 74HC4051. It also provides the two pins not used on the Seeeduino XIAO plus ground and 3.3V power.
Below are the sketches that use this board.
This sketch displays the set voltage and current limited values and the actual values while charging Li-Ion batteries. The charging voltage is adjustable to 12.6V (3 cells), 16.8V (4 cells), or 21.0V (5 cells) depending on the number of cells. The default current is limited to 1250mA or can be set to adjustable using a potentiometer.
Feel free to contact me at: carl dot nobile at gmail.com