In this tutorial I show you how I've build a homemade electronic load with Arduino, an LCD, rotary encoder for the menu and a power MSOFET for load control. It also has a good cooling system so it could handle high loads. See how to make the circuit, the case, connect everything, see the code I've used and which modules and make the same project. Hope you like it. If this tutorial helps you, consider supporting my work.
This are all the electronics we need for this project. You also have a list with some other parts we need such as plywood, the cooler, the 3DF printed fan covers and screws. The electronics are easy to use. All modules are using i2c communication. For the heat dissipator I've used a PC cooler and works great. You will need thin wire for 5V connections but thick wire for the MOSFET and power lines. For the drone we need: 1 x Arduino NANO: LINK eBay 1 x i2c LCD display: LINK eBay 1 x ADS1115 ADC: LINK eBay 1 x MCP4725 DAC: LINK eBay . . See full part list Part 2 - Schematic
• Let's talk about the schematic. Is important and you might need to adapt it to your needs. First of all, 12V from the DC adaptor is connected to a toggle switch and then to the Arduin o Vin pin and the fan so when we toggle the switch, everything is powered on. The NANO has a 5V regulator and that will be our Vcc. Supply all modules to Vcc and GND and connect the SDA and SCL pins from the Arduino to all i2c modules (ADC, DAC and LCD). • Connect the encoder to Vcc, GND and the 3 pins to digital pins D8, D9 and D10 of the Arduino. Connect the push buttons to pins D11 and D12. Also connect the buzzer to D3 for PWM signal for tones. • About the voltage divider. Please read the code and the next parts of the tutorials. I've used 10K and 100K but those are not exactly these values so we need to adapt the multiplier in the code. Read the code. • To read the current I use a 1ohm shunt. We read the voltage on this load in differential mode with the ADC. Again, this resistor is not exaclty 1ohm, so the multiplier will be adapted in the code. Read that part later. Connect the DAC output to the gate of the MOSFET. Load+, Load-, S+ and S- are the banana connectors we haev on the front panel. That's it. If you want the controller to go more than 2.1A, you will need more voltage at the MOSFET gate then 5V that the DAC could give. For that use this second schematic with an OPAMP between the DAC and the MOSFET gate.