Mecanum Wheel Robot Issues

Well here is a new wrinkle in getting this robot car built.  I have two of the TTGO ESP32 devices and when I plug them into a USB port, I get a message from Windows that there was an error and the device was not recognized.  This happens with both ESP32s, on two different Windows computers, using two different USB cables!

One of the TTGO devices had to work at one time as I have previously retrieved it's MAC address and I have uploaded Bill's mec-robot-remote.ino file to it, but I had left Bill's device's MAC address in the code.  You may ask, as I have, why didn't I use the MAC address of my own robot car.  Good question that I can't answer.  Guess I was just testing and wanted to see what popped up on the screen when the car could not be found.

I have a third TTGO on order from Amazon, so maybe I won't get an error message with it.  But I'm not confident that will be the case, as I have a stinking suspicion that this might be a Windows issue! 

Hi Steve @codecage,

  I rather fear I am preaching to an expert, but have you looked in Device Manager, which is sometimes easier to find by going to Control Panel first?

You are looking for some 'yellow-ish icon', with triangle and exclaimation mark attached to a USB entry. It is worth looking both when the USB is plugged in and when it is not, as unplugging and plugging the USB plug triggers Windows trying to 'allocate' it.

Of course the exclaimation mark is often a hint that you need to start searching for a driver ... but that is another art in its own right, so post again if it becomes a driver search job!

Best wishes and good luck, Dave

#davee,

Thanks Dave for the suggestion, but have looked and there are no noticeable error indications in Device Manager.  I'll keep looking! 

Hi Steve @codecage,

As I am sure you know, it is a pity there is nothing in the Device Manager, because that often contains the name of the device that needs a driver...

  Still guessing in the dark, but you say "I get a message from Windows that there was an error and the device was not recognized. " .... which I guess a is 'pop-up message' down by the clock that disappears after a couple of seconds. I don't suppose it mentions the name of the device it didn't recognize?

Otherwise, looking at the TTGO board, can you see a number on a chip that is likely to be the USB chip ... typically small square chips with 20-40 pins near the USB ... sometimes CHxxx (like CH340), or CPxxxx (like CP2102 or CP2104).

I just Googled 'TTGO ESP32' on AliExpress, and found the advert mentioned the two CP numbers in the specs part, choice depending on the version of board. If the board you have, looks like the advert, I would imagine the chip you want to look at is just behind the switches, roughly halfway between them. (Of course, they sometimes come with weird numbers or no numbers ... but you might be lucky!)

https://www.aliexpress.com/item/1005005504939754.html

If you find a chip number, you can probably find a driver by Googling.

I'll keep my fingers crossed for you!

Best wishes, Dave

Update!

A new TTGO just arrived and it connects just fine to both computers using both cables!  Really strange as the other two TTGO devices have be sitting undisturbed in their small shipping cases on my work bench ever since I first used them.

Go figure!

That's an odd problem! One possibility is that somehow the firmware on the TTGO boards got corrupted.

There are a number of instructions for reloading the firmware on YouTube, here is one of them:

Of course, I can't make claims as to the accuracy of the video, and there are a few more as well.

Good luck!

😎

Bill

Next issue!  When trying to compile and upload both the car and remote code I get an error that keep upload from working.  It looks to me more of  warning, but for some reason gets flagged as an error/

It is a variable not used error.  Around line 284 in the car ino and line 234 in the remote ino there is a "result" and a "result2" that aren't used anywhere else.  Is there a way a warning can be ignored and not be turned into an error?  Or is something else going on here?

@codecage 

A "variable not used" warning just means that you've defined a variable but never assigned a value to it or referenced it anywhere else. In other words, it's a waste of space and you can usually just ignore that warning.

You can (or should) comment out the declaration if you want to remember what value was 'removed' in case you find you why it was supposed to be used for later (you may find a reference to it later in some other commented-out code 🙂

It's not usually enough to halt compilation or prevent creation of an executable object.

Hi Steve @codecage,

 Others may have more specific advice, but as a quick workaround to keep going, check your IDE preferences regarding types of Warnings it flags up ...

I found when it was set to -Wall (or something like that), it treated things like a variable being created but not used as a 'hard error' and stopped the compile/link process proceeding.

Changing it to a more 'tolerant' alternative allowed it to proceed.

Best wishes, Dave

@davee You beat me to it this time Dave, but I am quite ill today. Never fear, I will bounce back but it could take a few months then I will be back to my normal feisty self.

Hi Ron @zander,

  Really sorry to hear that you are having a 'bad patch' ... wishing you a rapid improvement!

  As for being in a race to be the first to reply ... for a bit of fun, I am always up for a minor race or challenge ... but for me, the fun is more in the activity than in the winning or losing ... so I'll look forward seeimg you back at the starting blocks on the keyboard really soon!!

Take care my friend and best wishes, Dave

Duh!  Why didn't I see that?  My setting was to "All" but I don't remember changing to that.  Guess I'm having a tough time seeing with this eye condition I've been fighting flaring back up.

Thanks for the responses!

Hi Steve @codecage,

  Sorry to hear your eye condition is still bothering you ... hope you fully recover soon.

  As for the actual problem, I have a feeling someone has quietly changed the rules, (maybe between 1.8 and 2.0?? I don't really care!), because it caught me out when I reran on old sketch. It was pure chance I thought to look in the Preferences section ... on another occasion I might still be trying to fix it. 🤨 

Best wishes, Dave