STC8H3K32S2 drives backlit LCD voltage and current meter

A voltage and ammeter driven by an enhanced stc8H3K microcontroller with 12-bit adc. Choose a 2-inch POS machine 12864LCD screen with backlight for 2 yuan. The total cost is about 10 yuan.

It can display voltage, current and load resistance at the same time. It displays 99.9 ohms when there is no load. Capacity value, energy value, elapsed time, MCU power supply voltage and other information.

Component structure on the back.

After powering on, if there is no calibration data in the microcontroller, it will automatically enter the calibration program. Press the SET key to select the calibration parameters. VX is the voltage dividing resistor multiple. Enter the standard voltage at the VIN terminal. Press SW2 to increase and SW2 to decrease to adjust the display voltage and input. The standard voltage is the same. V0 is the zero adjustment value of the voltage. If it is not zero when there is no voltage input, adjust it to a number so that the voltage displays 0V.

IX is the current amplification factor. Input the standard current at the IIN terminal, press SW2 to increase, press SW2 to decrease, and adjust the displayed current to be consistent with the input standard current. I0 is the zero adjustment value of the current. If it is not zero when there is no current input, adjust it to a quantity so that the current displays 0A.

After the calibration settings are completed, press SW3 to exit to the normal interface.

front Photo.

Backside photo.

In order not to waste, according to the routine of the STC8H chip, a square wave generator module is added, which can be entered by pressing SW3. A square wave signal with a frequency duty cycle of 100-65000HZ can be input to the P2.0 port. Press the SET key to select a setting between frequency and duty cycle. Press and hold SW3 to exit.

1000HZ50% square wave output.

2800HZ output.

2800HZ, 35% duty cycle square wave output