"Aliens" Inspired UA-571C - airsoft turret - having trouble with running 3 servos - ESP-32 Cam

@jimcola Sorry, you need to be a lot more specific in telling us what your problem is. 

@jimcola If I understand what you wrote, you may need to take a very basic course in electronics. If you have 3 identical servos, then the voltage needed is the same for 1 or 3 or 300. The current will increase in direct proportion though.

If you have different servos that require different voltages it gets a bit more complicated but not that much.

@jimcola

Your post is somewhat confusing because in the text you say that only pan and tilt are working but in the video it appears that pan and trigger are working and tilt is not working. Is this an old video ?

Since you haven't given us a lot to go on, I'm going to assume that you are using 3 identical servos and one Arduino. Your power source at 6.5 V should power all three servos provided they are all the same type and voltage and are being powered by that source and NOT via power routed through the Arduino. The controller can (probably) also be driven from the same power source.

I'm also assuming that the video is correct and that the pan and trigger servos are working and the tilt servo is NOT working. If this is wrong, then just shuffle the names in the following.

There are a number of testing procedures you can try out

1) verify that the tilt servo is connected to a PWM capable pin on the Arduino (usually indicated by a ~ on the board and clearly indicated on online pin charts).

2) double and triple check all your wiring (using a multimeter if you have one) to make sure that the servo is getting power as expected.

3) double and triple check your wiring to make sure that the servo signal wire is properly connected from the Arduino to the servo signal input (again, use a multimeter to verify)

4) If you have another servo with a suitable voltage, replace the tilt servo with it (no need to connect the servo arm) and see if the replacement servo works properly. If it does, the tilt servo needs to be replaced.

5) If you don't have a suitable 'spare' servo, then swap the tilt servo with one of the working ones. If the replacement works after the substitution, then the old  tilt servo is probably faulty.  If the replacement doesn't work either then your wiring is incorrect (incomplete) or your sketch is incorrect (incomplete).

If all of these fail, let us know which test failed, how it failed and any other steps you've taken to track down the problem.

@will You have so much more patience than me.

@jimcola Those are EXCELLENT trouble shooting steps. Just follow the excellent advice and don't be tempted to go off on your own.

Posted by: @will

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I'm also assuming that the video is correct and that the pan and trigger servos are working and the tilt servo is NOT working. If this is wrong, then just shuffle the names in the following.

Thanks Will.  Yea,  I moved things around, switched PWMs, tried PWMs on different pins, So at first - the pan and trigger worked, then (after moving things around) the pan and tilt worked.  Wasn't sure what was going on.

I think I am just gonna start from scratch.  I got some more servos on the way along with a servo tester.    

Hi @jimcola,

  @will's previous message has helped you do some appropriate tests, which is  a great start. I'll try to complement that with a follow-on analysis.

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  If you analyse the evidence you should be able to focus on the real problem ... albeit, this can be a 'famous last words' type of statement. Anyway, I'll try to make a start, bearing in mind I can only get so far with the limited information you have provided so far.

   So if I understand your symptoms descriptions so far correctly, you have seen all three (pan, tilt and trigger) servos working, but of tilt and trigger, only one of them at any one time.

And I assume that you have been swapping the connections between the tilt and trigger.

I shall also assume that each servo obtains its power directly from the 6.5V supply you showed, and its control signal directly from an output of the Arduino.

As the pan servo worked for both tests, let's just leave it connected and working, so that we can concentrate on tilt and trigger.

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As you have seen all 3 servos move at one time, a reasonable assumption is that the actual servos are fine, the problem is with the electrical drive.

Similarly, it is less likely to be a problem with the 6.5V supply wiring to the servos, providing you did not swap either the +6.5V line, or the associated 0V line. That is, you were only swapping the control lines going to the Arduino.

If however, you were swapping either or both of 0V and +6.5V lines, then these are still potential 'suspects', albeit the control line is 'more likely'.

As a backup check, if you have multimeter, you should be able to check there is 6.5V at each servo at all time that the system is powered, regardless of whether it is moving.

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So assuming all three servos have 6.5V, but only one of tilt and trigger is working at a time, and that you can swap which works by simply swapping the two control signal wires to the Arduino, we can then suggest the problem is 'within' the Arduino board. 

The likely possibilities are:

1. One of the Arduino pins chosen for the control signal does not have the appropriate 'capability'. Arduino pins can be configured to do different tasks, but there are limitations.
2. The software is not driving one of the pins correctly.
3. An output pin of the Arduino is faulty.

At this point, we need some more information from you, to make any further progress. I suggest:

1. A list of main components, specifically Arduino type and servo type. Also a link to the servo data sheet.
2. Which Arduino pin connects to which servo
3. the software listing
   1. (Please try to post it to the forum as described in the forum instructions, or as an attached file. Avoid just 'simple' copy and pasting. Before you hit 'ADD REPLY', click 'Save Draft', and 'Preview', which are just below 'ADD REPLY' button to see what it looks like.)
4. With the configuration you have just described, which servo is working and which is not.

It is always difficult to diagnose systems by mail, but with this information, someone on the forum may be able to spot a problem or suggest a more specific test.

Best wishes and good luck, Dave

@davee FYI @jimcola I have a new nickname for you, "ObviousDave" or OD for short. Maybe with a little re-work this could be put into a Troubleshooting 101 topic. Better still, let's merge your response and @will removing any of yours that Will already covered. 😀

On a more serious note, I do believe there should be a noob section on basic troubleshooting techniques and between the two aforementioned posts we have a start on that.

AND, maybe a second sub-category, on common errors.

Hi Ron @zander,

  Sorry if there are any duplicates I have made, though I haven't spotted them, but I deliberately tried to ensure my message was not a duplicate of @will's, but rather a complementary follow-up using the information provided by @jimcola, who has followed Will's instructions.

As for whether it is obvious or not depends upon the person's experience. Obvious to you (or me), does not mean it is obvious to those less used to debugging systems.

My judgement, based on @jimcola's ending, "I got some more servos on the way along with a servo tester. ", after showing that all three servos could move in at least one of the tests, is that Will's instructions had already shown the servos to be fine, and the problem had to be the servos were not getting the right command signal, or less likely, but feasibly, if the power connections were being swapped, then it could be related to the power wiring.

Best wishes, Dave

@davee It does sound like duplication to me, but perhaps I am too experienced. Not convinced he followed Will's instructions, sounds more like what we in the troubleshooting business call 'shotgunning'. He demonstrates in the video that he does not know basic ohms law etc when he asks if he should increase voltage or amps. This means it will be a slow process to help him especially if he is unwilling to follow instructions as so many are and he is showing signs of.

Given we have not seen a pic of his wiring on the esp32-cam end, nor the code, it will be slow to resolve. There is a much quicker and effective way to troubleshoot this.

Since he already has 2 of you helping, I will just observe and enjoy watching.

@zander I hate you so much Ron.

@jimcola I am pleased that at least you are passionate about something.

Posted by: @jimcola

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@zander I hate you so much Ron.

Ron's mention of "shotgunning" is perfectly valid, since your response to my post above was "Yea,  I moved things around, switched PWMs, tried PWMs on different pins, So at first - the pan and trigger worked, then (after moving things around) the pan and tilt worked.  Wasn't sure what was going on." You offered no details as to the results of any proposed test so we are left without any possibility for refinement of your predicament.

As you have found, electronic circuits don't always work the first time and everybody here has had experiences in the past where they've had to engage in activity which will lead them to discovering what the problem is and thereby allowing a correction to be applied. The successful members have developed their own methodology for separating the problem into smaller assemblies and testing each of them to narrow the source of the fault.

The suggestions @davee and I made above were intended to help you start by making simple changes to the existing circuit and describing what a failure on each test would likely imply as the faulty component or connection. From your reply it appears that you didn't make any notes or organized attempt to deduce from the observed behaviour after the changes to identify the problem(s). 

And finally, you say that "I think I am just gonna start from scratch." by which you're telling us that you don't appear to be serious about FIXING the problem and will just keep starting over until it works. While that is a perfectly viable way of developing circuitry, it assumes that your original assumptions, construction, methodology and and circuit are faultless ... otherwise you'll have a continuous string of failures.

The point is, if you're not interested in, nor willing to indulge in trying to find the error(s) in a device you've constructed, then there's not much point in asking us what we can do to help you, is there.

I'm not disparaging you nor your skills nor your development strategy, just explaining why you probably won't get much help on the forum.