I would like to purchase this dual H-bridge module. I plan on connecting it to an Arduino Uno. In the products datasheet the specified power supply (Vd) is 6.5-12V, and the voltage for the motor control pins is 2.3V HIGH and -0.3V LOW.

My question is whether this product is compatible with the standard 5V of Arduino Uno for both the power supply and logic; i.e. can I connect the Vd to the 5V terminal of the Arduino and the control pins to the digital terminals?

If not, what modifications do I need in order to use this H-bridge with an Arduino?

Note: Originally I bought this cheap module and connected the motor control pins to the Arduino, but each output returned a different output voltage!

  • Yes, it's compatible with the Arduino, but realistically speaking it is not compatible with motors or batteries. The L298 (L293, etc) is a terribly lossy, antiquated part based on bipolar transistors, and only keeps showing up as module vendors have latched onto intertia from past usage dating from 20 years ago when there were few alternatives. Get something modern that uses FET's instead. – Chris Stratton Jan 13 '18 at 16:54

That's a very poor datasheet. I think it's using equals signs where it means less-or-equal, so:

High level: 2.3V = Vin = Vss

Intends to say that Vin between 2.3 and Vss will be considered high, and

Low:-0.3V = Vin = 1.5V

Intends to say that Vin between -0.3 and 1.5V will be considered low.

"Vss" in the high level definition is confusing, because in the rest of the datasheet, "VD" is used for the logic voltage and "VS" is used for the motor; you'd expect the upper limit to be the logic voltage.

The diagram at the end of the datasheet shows how it can be used with an Arduino. A 7.5V source is going into the Vin pin (instead of the barrel jack, which is unusual). There's a protection diode on the power input which incurs a ~1V voltage drop, so the Arduino Vin pin should be outputting 6.5V, which drives the board. The digital outs from the Arduino, when driven high, are at 5V, well above the 2.3V threshold given on the datasheet.

I'd recommend powering the Arduino through the barrel jack with a 7.5V or 9V supply to drive the logic side of the board. (Powering through the USB port will put 5V or less on the Vin pin.)

You'll want a more robust supply for the motor side, because the Arduino can't deliver very much current.

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