Current and voltage meter-USB tester-V2.0

Old version https://oshwhub.com/47415Y/hk32f030mf4p6-dian-liu-dian-ya-biao-shi-yan-dian-yuan-ban-lv-47415y

Current and voltmeter, powered by battery, can set protection voltage and current.

The onboard OLED screen, buttons, and LED lights can also be used as a small development board.

Use INA226 to collect current and voltage. 0-36V, 0-5A. 0.9-inch OLED using I2C. It is powered by lithium battery and USB type-c charging is convenient to use and avoid interference.

It is mainly used as an auxiliary device for old-fashioned experimental power supplies (the kind that adjusts voltage with a potentiometer) and is used in series with the output line of the experimental power supply.

A new USB input has been added, which can be used as a USB power test meter.

The main function:

1. Display voltage, current, and curve.

2. The protection voltage and current can be set. When the protection range is exceeded, the output will be turned off to protect the back-end circuit.

3. It replaces the "OUTPUT" button of the experimental power supply. There is no output every time it is turned on. After confirming the voltage, press the button to turn on the output. Prevent the experimental power supply from being misadjusted or the potentiometer being damaged.

In addition, the PCB panel and back cover are designed and connected using M2 copper pillars.

1) When starting up, the output is turned off by default and the last set protection parameters are loaded (EEPROM).

2) There are three pages 1, data display 2, curve display 3, parameter setting. Press and hold the SET key to switch.

3) In the data display & curve display interface, short press the ADD key to turn on the output, and short press the SUB key to turn off the output.

4) In the parameter setting interface, short press the SET key to switch the cursor, and short press the ADD key and SUB key to add or subtract parameters. Long press the ADD key and the SUB key to quickly add and subtract parameters.

Long press the SET key to exit the setting interface (save the parameters to EEPROM at the same time).

5) Parameter settings can set protection

Voltage 0-36V

Current 0-5A

Power 0-99W

Curve voltage range 4.5V 9V 18V 36V

Curve current range 5A 2A 1A 0.5A

Curve drawing time 1 time 2 times 5 times 10 times

6) The battery voltage and temperature are displayed in the lower right corner.

2021.7.4 Hardware version V2.0 

Re-layout the board, removed 24c02 and used internal FLASH EEPROM

The hardware adds USB input and output ports, and the sampling resistor is moved behind the MOS, so there will be no no-load small current.

The PMOS driver adds the ICL7660 negative voltage driver, which solves the problem that low-voltage MOS cannot be turned on.

LED IO changed to PD1

The IO sequence of buttons has been changed

If the set parameters are incorrect, you can first run force_init_flash_eeprom(); and then comment them out.

The temperature display is added and the boot image display is removed (FLASH is not enough).