[Hangshun Training Camp] Current and Voltage Meter-Experimental Power Companion 47415Y

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

Onboard OLED screen, buttons, LED lights, 24c02, 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.

Compatible with STM8S103F4P6.

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.

Note: R18 is not soldered, so be careful when applying copper on the top cover to avoid covering the LED light-transmitting hole.

Legacy test program

111.zip

---------------2021.3.24-------------------------

The panel was redone, and light holes, switches, and USB holes were opened. 1.0mm thick PCB.

It is just right to install the panel with M2*3 copper pillars, which can make it easy to press buttons.

There is no problem with the PCB hardware of the first version, and the two PMOS tubes are correct. Can prevent current backflow.

{

The second version of the PCB optimized the PCB routing and layout. I thought that the two PMOSs on the first version of the board were wrongly drawn. It turned out that the first version was correct, but the second version made the mistake. ^@^

Using the first version of the PCB and the second version of the front cover. The rear panel has not been made yet. There is no need to fly the flying wires on the PCB, they are originally correct.

The third version (unfinished) plan is to change the sampling resistor behind the two PMOS, and connect the output indicator light to OUT_EN to solve the problem of static current.

The connector can be changed to 5.08 which is stronger and has greater current. It is enough to use tp4057 for charging.

}

A 650mah lithium battery is used, and the charging current is about 300ma.

The program has been initially completed (the program was written relatively amateurishly, so pat). Rewritten the settings page. 111-3.23.zip

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 is displayed in the lower right corner.

--------------------------------------------------

front

reverse side

side

Data Display

Curve display

parameter settings

Parameter setting page

-------------------------------------------------- ------------------------------- Supplementary video https://www.bilibili.com/video/BV1ih411S7BH/

-------------------------------------------------- ------------------------------- 2021.4.24 Program V0.3 Update 111-4.24.zip

1. Changed the handling (rewriting) of EEPROM if data is wrong.

2. Determine whether INA226 is normal.

3. Added a boot initialization page to display the version number and whether EEPROM & INA226 are normal.