I've got an R/C vehicle used in various stage demonstrations. Two motors (left and right) with tractor steering. The motors are gearmotors that pull less than an amp nominal and are rated at 25 amps stall. No caps on motor terminals.

Speed controllers are AI Super Reverse Digital controllers. (I have tried several different types of AI controllers with no affect on the behavior I am about to describe.) These controls self-calibrate them selves to the transmitter.

Transmitter is a Spectrum DX5e. Only two channels are used with the sticks forward - center off - reverse.

Battery is a 7.4v LiPo.

Here is what is happening: Testing in the shop, everything works great. Power up the transmitter, power up the vehicle, receiver lights up. The vehicle drives forward and back as it should.

When you get to the stage situation, all hell breaks loose. The vehicle might 'boot' with one or both channels inverted (forward stick reverses that motor). Or it might boot normally, drive correctly for a while, and spontaneously have one or both motors reverse the controls. Once in a while one motor/channel might go completely dead. The net of it is that the vehicle is spontaneously uncontrollable.

The one thing I know is that everyone there has a cell phone, so perhaps whatever this is is exacerbated by interference???? Or are the receiver/controller.motor components mismatched? I feel confident that the problem is not any loose connections or an undercharged battery.

My first posting, thank in advance for your help.

I would tend to agree with your thinking.

If it works fine in the shop and experiences glitches on the stage, it sounds like something in that environment is causing interference. I haven't seen any complaints that cell phones cause interference with 2.4Ghz setups though so I would b looking for other source(s).

You are following right turn on procedure? Transmitter is always turned on 1st, then the rcvr. Other wise there can be probs in picking up other signals.

Yes, power up procedure is always the same, transmitter on first, etc.

It is like the controllers are getting themselves confused, and randomly selecting the 'wrong' calibration. Why does this happen - are these controllers junk - and why does it only happen when there is a lot of RF around? BTW it happens EVERY TIME like this. Not random. In the shop, fine. On stage, all messed up.

Cannot function like this - what can be done?

I had a couple of those LRP AI Super Reverse when I picked up a used Associated T4 truck from eBay. THose were the worst ESCs I've ever used. I had the "forward one time" then "reverse the next time" syndrome because of the autocalibration. I say they are throw-aways if you can afford to go with new ones.

You may find some used cheap brushed motor ESCs on eBay. Anything from any vendor who offers calibratable (one-button setup) type ESCs would be fine. You will find dozens available due to the plethora of people going to Brushless racing or driving and selling off their old stuff.

Could you get by with other LRPs too - the Quantum is one that is a brushed controller but doesn't do the AI stuff. Some older hobby shops may have some laying around they'd offer you at a discount (to get it sold).

I think you are on the right track. It could be the combination of the DSM controller and the AI ESCs. Maybe the presence of a large number of cell-phone-and-electronic-device-toting people is enough to get the controller to hiccup. Maybe then the AI ESC's autocalibrate themselves in the wrong direction.

I picked up a pair of Novak Rooster ESCs. They require manual setup. Maybe then they will never forget. I could try these in the vehicle. My only dilemma is that there is not practical way to test it until it's too late to do anything about it if it fails again.

I wonder if items like the Spektra transmitter are certified for use in 'noisy' environments? Most R/C applications are not around large crowds with cell phones and whatnot. Am I on the wrong track with DSM? Should I convert to analog?

I really want to take steps to avoid embarrassment the next time the curtain goes up.

Not sure if it's your ESC or radio but I've read that FHSS is better at dealing with lots of interference than DSSS.

If you have access to another radio, try it, flourescent lights, wireless routers, power lines all can cause havoc with radio systems.

I'd have to lean toward the ai systems being the culprit here. You can find new one-touch setup Brushed speedos like the Dynamite Tazer for under $50. I wouldn't recommend them for race use but they seem to be pretty solid for basic functions.

No access to another radio.

Wondering about switching to Novak ESCs. They require manual setup for forward and reverse. Once programmed, do they retain memory? IOW if some interference causes a glitch, do they just come back online remembering that forward is forward? Or do they require reprogramming?

I can deal with a momentary glitch where the ESC remains properly calibrated. I can't walk on stage to reprogram the ESCs, LOL.

Once the esc is set manually, it remembers the full throttle, full reverse and neutral settings until your reset it. Pretty tough to screw up if you follow the directions, and will work pretty much forever unless you jack with radio settings or switch radios.

This can actually be helpful for tuning from your radio as it allows you to move the throttle/brake endpoints down (slower/softer) or up to essentially 'over clock' your speedo (not recommended).

An AI speedo recalibrates itself every time you turn it on, so if you have your finger on the trigger/stick by mistake it'll misread neutral, and it 'learns' full throttle and full brake/reverse when you use them.