Friday, 2 November 2012

Final Prep

In readiness for R2 to take his first steps tomorrow, on Tuesday i finally hooked up the chains from the motors to the wheels and powered up the Sabertooth.   The drive trains ran fine, but it did not go well :(


1.  When it got to top speed one motor would freeze, but only at top speed and only on one motor, when i swapped the supplies it did the same, so it wasn't in the code.  Only by trimming the speed down from 180 to 165 and 0 to 30 did it work reliably.

2.  There was a popping being heard on the audio, not good.  Only occasionally but mainly on direction or speed change.

3.  A couple of times its default speed was different so the motors would run slowly, this was not right, wasn't sure why and couldn't recreate it.

So had a bit of a play, tried different dip setting and tweaked the code here and there and still nothing reliable.  So contacted Dimension who suggested i send it back to be repaired.  Great customer service.

Wanting it running for the big test tomorrow and for the NEC on the 17th, I ordered another Sabertooth.  That arrived today.

Then i get back tonight, rewire a few things to make sure all the connections are clean etc. Reread the manual for the Sabertooth one last time and set it up how i assume it should be and give the old one one last try.  Annoyingly, now i have a 2nd one, the first one works beautifully.  I don't know if switching all the dips back and forth helped or if I hadn't found the magic combo before but it seems to be perfect now, full speed is no problem and it seems smooth, and no noise on the speakers either. Might just have needed the freshly charged 12v battery. :)  I did think it was odd, all the testing with it had gone beautifully.  

I'm going to keep an eye on it and see if the problems come back, but looks like i might be able to return the 2nd one. :)  But the 2nd one is a V2 so might do the ramping, then i could use the serial connection and the on-board mixing, the V1 wouldn't do the ramping, but the V2 might. Decisions decisions. :)

The magic combo on the dip switches was 1, 4 and 6 down and the rest up.  I think the main one was number 6, that was the auto cut off and auto trim, it did mean moving the stop point in the code to 96 degrees but works great now. I haven't had any of the original problems since.

I tweaked the speed of the slow mode and the acceleration based on what looks right from the speed of the  wheels, but i may well be well off on that, then swapped the turn in the code to help turn in the right direction, i hope i got that right, its pretty confusing :)  So i reckon we might be ready to test the real driving tomorrow.  I quite fancy trying the 2-3-2 code tonight too.  I'm feeling brave after that success.

He doesn't look too dignified at the moment. :)

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