tracked robot chassis team

LUG 29.11.14

Present:  Mike Hull, Richard, Kieran, Kieran’s Nan, Tony, Les, Arthur and Jack.

The tracked robot chassis team got to the point where they wanted to see if the motors would turnover. The chassis has two geared motors one for each track.  Built in to each of the side plates are a H-Bridge controller and also an opto interrupter attached to the motor shaft to return the actual speed of the motor.  Each plate has pins marked Vcc, GND, A1, B1 and Speed.  Without instructions to hand it was a case of  having an educated guess as to what the pins were for.

In the end with Les’ guidance and his trusty Arduino UNO it was confirmed that the Vcc and GND were for the power and A1 and B1 are the two sides of the H-Bridge.  We didn’t test but the Speed is probably the output from the opto interrupter speed sensor. Using a simple PWM based sketch Les and Mike got one side of the robot running both forwards and in reverse at varying speeds.  Success!

There was a demo and explanation of the motor in action.

The problems started when we tried to get the other side/motor working, a few things were tried but the motor just wouldn’t fire up using the H-Bridge.  Slightly frustrating after the initial success.  

The H-Bridge is a surface mounted 8 pin component with what looks like the 4 diodes surrounding it so it should be possible to investigate where the fault lies.  In any case Mike has ordered a PWM / H-Bridge device to go with the Ras-Pi so if the fault cannot be fixed it’s not the end of the world.

Apologies but I didn’t take notes on what other people were up to.  Jack is still mostly playing games with his new laptop.  Arthur was looking at Unity and trying to decide which of the two scripting languages offered is the best for him (Java vs Mono/C#).  Kierans Nan and Tony were dealing with internet connectivity issues.  

It was a great session which went very quickly, many thanks to Mike for his hospitality.

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