September 26, 2012
about a year ago
I am using the Wild Thumper and finally got all the bugs worked out, and found it had been replaced with this controller. I have not used the new board and I will most likely not use the new board. I figured I’d explain why.
At first glance I had hoped that the problems that plagued me with the Wild thumper had been taken care of, but after reading comments and looking through the specs, I’m skeptical whether this board is a proper upgrade. Compared to the complains in the comments on the Wild Thumper, the T'Rex appears to be more delicate. There are a long list of motor failures listing the same issues. To be fair, after a quick glance at the supplied code it doesn’t appear that the current sensing is being used in-code to limit the motors as the code does on the Wild Thumper. The only referances I can find are for reading the current and supplying a value in mA for testing and communications. As such it appears to be relying on the speed of the resettable fuse to protect the motors and not limiting the amount of control signal transient to the controller, effectively allowing the motor to be able to be switched on hard fairly quickly. I would suggest that anyone who uses this board go over the code very carefully and add in the current limiting code from the Wild Thumper at the very least, if not come up with something better. Since, for me, all links on this site redirect to this board (including the “previous versions” link), here’s the link I found to the board: https://www.sparkfun.com/products/retired/11057 I’d say to get the code soon, it’s getting hard to find documentation for that board. Nonetheless, the motor controller does not look appealing after dealing with the issues I had on the Wild Thumper (bad soldering, and one controller would intermittently cut out for no apparent reason)
In my opinion, the T'Rex might be a great board for someone who has a skid-steer RC that might want to augment it with an arm or collision sensing, but as for the ability to add sensors and other useful robotic devices, this board is starved for available I/O. There are only 2 accessible Analog inputs (via I2C connector) versus the Wild Thumper’s 5, and there are less Digital I/O. I had to cut my project back due to lack of available I/O already, and lost features to squeeze everything I could out of the board. I can’t use this board as a pure robotic controller. (1 servo, 5 IR reflectance sensors, 4 remote control inputs, 2 mode selection switches and so on, on , I don’t have a list in front of me).
I’m glad there’s a strong motor controller available, but for my purposes it’s not quite a direct replacement for the Wild Thumper.
about 2 years ago
Anyone have issues with the driver output cutting out?
I’m using a 7.2v 10000mah Nihm battery, the controller, and two 7.2v gearmotors. My code is set up to run both motors at the same time at the same speed (with a modifier to make up for the slight difference in speed, simply adding 6 to one). I have additional power control as well as modified origional overcurrent protection (if one motor circut overloads, both shut down).
It was working great and I was getting the bugs worked out, and now the right motor output stalls (motor stops) intermittantly in one direction. I haven’t be able to check everything yet, but I suspect on of the drivers on the H bridge. Anyone else have this problem?
No public wish lists :(
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