First I tried a small H-Bridge with 2.5 A to supply the DC motors with energy. But this type of motor driver was too small at that point the robot tried to turn on spot the motor driver burned out. Then I bought an upgrade for my Big Rob and now I am able to drive around and to turn on the spot without burning the motor driver. I searched for a motor driver with more than 10 A on each motor out. I found a motor driver with a total of 43 A and it could be controlled by a Raspberry Pi. I decided to buy two BTS7960B motor drivers because they are able to supply a total of 43 A which is more than enough for my four dc gear motors.

The picture below shows the two motor drivers and the Raspberry Pi wired and  placed on a cardboard inside my Big Rob.

Big Rob BTS7960B Motor Driver 43A H-Bridge

Big Rob BTS7960B Motor Driver 43A H-Bridge

To make is easy for you to find the motor driver BTS7960B I used for my robot I added an Amazon online shop link.

Balance World Double BTS7960B DC 43A Stepper Motor Driver H-Bridge PWM
Price: $19.99
1 new from $19.990 used
100% brand new and high quality Quantity: 1pc Weight: 66 g Input voltage : 6V-27V Maximum Current : 43A Input level : 3.3V-5V Control mode : PWM or level Duty cycle: 0 to 100% Current conditioning output: yes Size:50mmx40mm/1.97"X1.58"(inch) (approx) Features: This driver uses Infineon chips BTS7960 composed of high-power drive full H-bridge driver module with thermal over-current protection. Double BTS7960 H-bridge driver circuit, with a strong drive and braking, effectively isolating the microcontroller and motor driver! High-current 43A ? Specification: *Double BTS7960 large current (43 A) H bridge driver; *5V isolate with MCU, and effectively protect MCU; *5V power indicator on board; *Voltage indication of motor driver output end; *Can solder heat sink; *Just need four lines from MCU to driver module (GND. 5V. PWM1. PWM2); *Isolation chip 5 V power supply (can share with MCU 5 V); *Able to reverse the motor forward, two PWM input frequency up to 25kHZ; *Two heat flow passing through an error signal output; *Isolated chip 5V power supply (can be shared with the MCU 5V), can also use the on-board 5V supply; *The supply voltage: 5.5V to 27V

Connecting the BTS7960B motor driver

You need six female-to-female jumper cables to connect the motor driver with the Raspberry Pi. Two cables are needed to supply the logic of the motor driver with 3.3V (VCC and GND). Two wires are needed to activate each H-Bridge with a high signal generated by the Raspberry Pi to set the spinning direction of the DC motor (R_EN / L_EN). The last two female-to-female jumper cables are needed feed the motor driver with a PWM signal to control the speed of DC motors (RPWM/LPWM).

The picture below shows the wiring of the motor driver.

Big Rob BTS7960B Motor Driver 43A H-Bridge wired

Big Rob BTS7960B Motor Driver 43A H-Bridge wired

BTS7960B Python program

I had to re-write my Python program I already developed to control some L298N H-Bridges to control the BTS7960B motor driver. That’s make it very easy for the Python control program to import the new BTS7960B Python program as an module and to control the motor driver without changing anything in the control program.

I uploaded the Python program with some inline documentation which describes which GPIO pins are used. This is important for wiring the motor driver.

download: Big Rob motor controller program L298NHBigrob.py

Summary

The wiring of the BTS7960B was strait forward and with all my experience in building robots very easy. The re-use of my already developed Python programs saved me a lot of time and after a few minutes I was able to driver around with the Big Rob and the new motor drivers. It is very cool to have a strong robot with a lot of torque to drive around.

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