The H-Bridge is a basic part to control motors. Here I am going to explain how I used this H-bridge, Qik 2s12v10 Dual Serial from POLOLU.
I am using it now for my Sumo-bot. I think is fairly good for medium size motors (untill 30A peak and 13 A continuous mode). The price is arround $75 plus sending.
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We start talking about what is a “H-bridge”. One H-bridge is a intermediate control phase between microprocessor and motors. With this element you can convert the low intensity microprocessor signals into power signal to feed and manage the motors.
One microprocessor can only take out arround 50 mA in each out-pin and one robotic motor can consume form 150 mA to 2 or 5 peak Ampers. In this case, our powerful motors could drain 5A in stall.
The basic circuit is make up with four transistors, MOSFET or BJT. The name of “h-Bridge come from the shape of the basic schematic diagram. See the picture below.
This pololu Qik 2s12v10 Dual Serial Motor Controller is controlled by a Serial Port. Usually this kind of electronic boards are managed by PWM outputs. With this type of H-Bridge we can check, control and limite more variables like acceleration, current limitation, erros and data feedback… With one single cable ( with also ground conection of course) we can also control speed and direction.
All the square pins are ground (GND) and you can not feed the board from the low intensity side (left, battery output). You must connect the source or battery on the right side. ( power side)
The motors connection is:
Is recommended from the manufacturer instal 3 small ceramic capacitors (0.1 uF) on each motor, so we avoid small peaks on the current
To setup the Serial speed, you must short the 1 and 2 jumpers (like shown below), and we will work with 9600 bps. If we want use auto-detect mode, we shold send a calibration command “0x00” via Serial. For other speed you can read user guide‘s baud rate table.