Using L293 motor driver

I have built an object avoiding bot using PICAXE 28x2, Sharp distance sensor, and the Tamiya double gearbox driven by the L293D motor driver. I seemed to have zapped one and the other will light an LED in both directions (red/green) but will no longer drive the motors. I also tried a L293NE and they don’t work at all.
I also noticed that the servo I am using a 9g Mini Servo works erratically (jitters) when I connect the motors and run the bot. If the motors are not connected, it works fine? There is some kind of electrical interference at play here.

I think I am using the wrong motor driver, any suggestions for a low cost alternative?



We have a few alternatives that might be much better than the L293. The smallest one is TB6612FNG, which should be fine if your voltage is not too high and the L293 was close to good enough. Otherwise, you might consider something like the dual MC33926 carrier, which can handle higher voltages and much more current.

However, your noise and servo problem is likely independent of your driver, so you will have to do things like improving your wiring, shielding, and power supply.

- Jan

The problem I have been having with the erratic operation of the bot had to do with the Sharp distance sensor and the bias into the PICAXE. I changed the resistor and all seems to be working now. Thanks for the feedback.

Could you direct me to a application schematic using the TB6612FNG. I am not sure of the pinout showed on the web page schematic for the unit. thanks.

We use that motor driver on several of our Orangutan robot controllers, including the Baby Orangutan. You can look at its schematic for an idea of how to use the part.

- Jan

Thanks for your input.
Turns out that the problem was with the Sharp IR sensor. I adjusted the bias resistor and it all works ok now.