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Asked — Edited

Running Into A Question With Iotiny Using Rotational Servos

I have built several Adventure Bots and have not had any issues, but when I tried to build a custom 2 WD robot using IoTiny I've run into a strange problem.

Using the same "continuous rotation servo with Wheel" set from my Adventure Bot I found that they worked for about a minute before refusing to run any more.

I thought it might be just a coincidence, so I took another working set and first tried that with a EZ-B v4 controller in a Power Shell with the same "LiPo Robot battery" (after a full recharge) that I was using on IoTiny ... and those wheels worked fine

But, when I connected the wheels back to the IoTiny, the servos worked for a little while and then stopped working!

What's worse, is that I reconnected the servos back into the Adventure Bot and NONE of then worked anymore.

Any ideas?


@Frank, That is head scratcher! One more test idea, what about meter testing it under no load? Scripting wise, still send the control signals, just don't connect a servo on the port.

And then maybe try a metered test on another I/0 port, again sending control signals to the port with no servo connected.

@Jeremie, is there a check list to check the I/o tiny with a meter for proper voltagages or continuity like there is for EZbv3? EZBv3 Diagnostics If not do you think you might be able to help us come up with one?
Hey guys,

I figured it out, but I gotta run. I'll let @DJ fill you guys in!

Oh and the IoTiny Datasheet is almost complete, it's just being edited and reviewed before release. It'll definitely help with diagnostics.
My IO Tiny runs the servos with no problems.
Could the tape be a problem?
@Frank... You're not crazy man... I just tested with the metal geared servos from my developer's kit I just got... Same thing happened to mine as it did to yours... Actually after running them at different speeds with the iOtiny trying to figure this out they no longer work period.. When I plug them back into the ezb4 they are dead, no worky..... I don't really care as I don't use 360 servos in my projects... My old resin 360 servos still however work fine with the iotiny and ezb4...

Anyway lets hope @Jeremie and @DJ will look into this...
It's not the IoTiny. There's a minor change in the latest revision of the continuous rotation servo pcb. It took Jeremie a loooong time to identify what was happening, and its such a rare situation for the IoTiny and these servo combination.

Contact us to warranty the continuous rotation servos.

However, in the meantime we are looking to see if there's a possible firmware solution, or if the servo pcb revision needs to be reverted.

Stay tuned.
@DJ... Thanks... I appreciate you guys efforts on stuff like this... Not to get off topic or anything. This is also the first time using the new HDD servos ... Not sure if anyone else noticed as the "no buzz feature" has been all the buzz :) lately but these new servos position so accurately as well. Way better than the old HD servos. They are very smooth indeed... Simply fantastic to say the least...:)

P.S. I broke those 360 servos and I would never use them anyway... Thanks for the warranty offer but I am good... No need...:)
Thanks for confirming this...

Thanks for the great support on your products. I did ruin a few in my testing as I couldn't believe what was happening as others didn't see the issue.

I will contact warrentee support

I agree that the new HDD servos are amazing

I'm expecting two new HDD rotation servos.

DJ mentioned the possibility of reverting the servo's PCB.

Is there away to know if is the old(good) or new(pcb) before i connect them to the Iotiny ?
I know the lever arm and 180 degree servos are now HDD but I haven't seen any mention of HDD for 360 degree servos

@Jeremie mentioned that the plastic gear 360 degree servos work with IoTiny

I finally got around to testing all the servos from my HDD upgrade order, and sure enough, the 5 360 servos all died when tested with an ioTiny.
The old 360 servos all work great with the ioTiny.
Not sure what the problem is, but I wouldn't try anymore new ones with the ioTiny until something is fixed.
both are fixed with latest hardware revisions. Using the old revisions together will cause this scenario. Contact Us if you used the old revision and experienced issues.


and sure enough, the 5 360 servos all died when tested with an ioTiny.
... Hind sight in all I personally I would have quit after burning up the first servo... But hey I was dumb... :P You burned 5 of them before stopping? LOL:) One has to ask what made you keep going after say the second servo gave up the ghost? LOL:D Did you run out of 360 servos to test or something?:)
I'm guessing @Alan may have been using an Adventurebot to test. That would take out 2 at a time.:(
I burned up several too in my initial testing because I couldn’t believe the results I was getting.

I just assumed I had bad parts as others were saying the didn’t have the issue

Thankfully, Jeremie confirmed the problem
I burned 4 using this setup:

User-inserted image

I had only 4 .... now i have 0:)
Fellow Builders, we are gather here today to pay our respects to ptp’s full rotation servos and thus his robot platform. Though his platform was not with us long, it left a memorable impression on all of those who saw it because it looked cool. Indeed, many wish his servos worked even at this moment so he could finish his project and post videos!

The life of a servo at times may seem short but for ptp these servos never matured to warrenty expectations. When one servo dies, another is manufactured and perhaps even will go on sale. We must remember to keep our part stocks up, so that we may never say we have zero servos!

Please, a moment of silence for ptp’s servos.;) lol


Hind sight in all I personally I would have quit after burning up the first servo

Yeah, well. I so go big or go home :), and hindsight is always 20/20.

Was the end of a long day, and the first time in many months I have had any time to spend with my robots. Decided I should test all of the servos I got in my HDD upgrade box (SIX, Roli, and Dev Kit upgrade) before the warranty ran out. I had already rebuilt Six, and was running through the rest of the servos. First one died, and I recalled there was a problem mentioned on the forum, but didn't go look it up. Seemed to recall that it was just some of 360's, not all of them (whoops) so tested all 5, and all 5 died. They sort of worked setting the port between 90 and 180 (movement was jerky, but working) and then as soon as I went in reverse, they stopped responding.

30 years ago I was working as a bench tech fixing computers. My boss walked in and I had 5 * 20mb Hard drives on the table that were over $1000 each (st-225) I had one more plugged in and I said this hard drive is faulty. I plugged it in and it burnt out. He said, did you try another hard drive? I responded, yes all of them are faulty. Turned out the power supply had an extension cable that was wired back to front 12v on 5v rail and I had spent the past hour destroying half a dozen hard drives.

Anyway my lesson learned that day was, always test 1 at a time and if you try 1 and it burns out you don’t just keep plugging new ones in.