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Trouble with 4 DOF T-HEX Robot


SoundBeat
(@soundbeat)
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Joined: 3 weeks ago
Posts: 6
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Hello everyone, I am working to trying to get a robot bought offline to work again after messing it up. I have solved bits and pieces and this is the stage where I am at now. The robot receives it's communication by a PS2 receiver module that is connected to a level shifter circuit board. The object controlling the robot is a PS2 controller. The PS2 receiver module is attached to this board with extender cables. https://www.robotshop.com/en/lynxmotion-botboarduino-robot-controller.html One day I accidentally broke the pins connecting the level shifter and the receiver module. As an attempt to put it back together I soldered it back. Turned on the robot and the led's on the receiver module did not blink which is confusing because the soldering should have ensured a connection. What do y'all think may be the problem? Also I want to post pictures to show you guys what I am talking about but I get something that says, "No more attachments are allowed today". Why did that happen?


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DaveE
(@davee)
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Joined: 1 year ago
Posts: 507
 

Hi @soundbeat,

   Sorry, I haven't any experience with the hardware you are talking about, others may be able to help more specifically.

Of course, all electronic components can be damaged, etc. but in my experience, the majority of problems in situations like yours are the connectivity is still 'broken' or 'incorrect', such as a short between two wires, and so on. I am sure you have tried very carefully to reassemble the system, but 'sneaky' connection breaks and shorts can easily 'hide in plain sight', and be very difficult to spot.

I would use whatever meters, scopes, etc. you have available, to triple check each of the connections, as well as looking for PCB tracks which are cracked, pins fractured from the PCB track at the solder joint, blobs of solder shorting two points, plugs ad sockets not making contact with each other, and so on ... unfortunately the list of such gremlins is very long.

If you can find out or work out what the signals, voltages, etc should be for each connection, then that is a massive help .. otherwise it can be a needle in a haystack problem .. you may be lucky or otherwise.  Use the web to try to find circuit diagrams and the like.

----------------

The "No more attachments" is because you are a newcomer ... sadly, the Internet is rife with malevolents, so it is a simple protection mechanism ... this restriction is normally lifted after the newcomer has posted a few messages.

Good luck with your problem. Dave


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SoundBeat
(@soundbeat)
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Joined: 3 weeks ago
Posts: 6
Topic starter  

Found the issue after diagnosing. The jumper on the circuit board seems to be in the wrong place not giving voltage to the circuit board itself. I do appreciate taking the time out of your day for answering my question!


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DaveE
(@davee)
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Joined: 1 year ago
Posts: 507
 

Hi @soundbeat ,

  Good to hear you found the problem .. sounds like it was yet another of those connection gremlins!!

Best wishes, Dave


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SoundBeat
(@soundbeat)
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Joined: 3 weeks ago
Posts: 6
Topic starter  

Another problem seems to come up again. I know for sure that hardware side of the robot is great but the software side is the last problem. There is a third party website that provides the code to the robot in here https://github.com/Lynxmotion/3DOF-4DOF-Hex/tree/master/BotBoarduino/4%20DoF%20Ready%20(untested)/BotBoarduino_CH3R_PS2 After plugging the code to into the robot, it didn't move after turning it on leading me to believe there are still bugs in the code or that it is incomplete. I do want to note that it did compile correctly. The problem that I am having now is that I am not sure where to start on the code in regards to fixing it as there could be many possible errors. A direction, a hint, or a guide would be extremely helpful to know where I could start at least.

 


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Ron
 Ron
(@zander)
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@soundbeat Did you also install the library it mentions. Personally I would not use that link, instead it mentions another github link that is more complete. Did you try that?

It is considered poor judgement to traverse a chasm in 2 leaps.


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Will
 Will
(@will)
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Posted by: @soundbeat

There is a third party website that provides the code to the robot in here https://github.com/Lynxmotion/3DOF-4DOF-Hex/tree/master/BotBoarduino/4%20DoF%20Ready%20(untested)/BotBoarduino_CH3R_PS2 After plugging the code to into the robot, it didn't move after turning it on leading me to believe there are still bugs in the code or that it is incomplete.

Which part of "(untested)" was unclear 🙂 ?

I was kidnapped by mimes.
They did unspeakable things to me.


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SoundBeat
(@soundbeat)
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Joined: 3 weeks ago
Posts: 6
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Hello Ron! Thank you for taking the time out of your day for taking the response. If the complete code you are talking about is regarding the 3 DOF T-HEX. I haven't tried to plug the code in the robot yet because I currently have a 4 DOF T-HEX and not the 3 DOF T-HEX. I can try and see if that works.

Hi Will! I understand that it said "untested". However, I just wanted to try and exhaust all of my options with the first being to see if maybe the code itself was fine and that "untested" meant that it had yet to be plugged into the robot. Now I know that the untested was stating that the code had yet to be complete. What I wanted to know is if the code that I plugged in from the 3 DOF files don't work, where would I start in terms of fixing the code on the 4 DOF files as I am not sure where to start?

This post was modified 2 weeks ago by SoundBeat

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Will
 Will
(@will)
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Posted by: @soundbeat

Hi Will! I understand that it said "untested". However, I just wanted to try and exhaust all of my options with the first being to see if maybe the code itself was fine and that "untested" meant that it had yet to be plugged into the robot. Now I know that the untested was stating that the code had yet to be complete.

Understood.

What I wanted to know is if the code that I plugged in from the 3 DOF files don't work, where would I start in terms of fixing the code on the 4 DOF files as I am not sure where to start?

Usually, when you're starting on a large complicated system, it's best to try to isolate one (simple) subsystem of the whole piece (try to comment out the calls and links other parts). Choose something that you can most easily understand and try to get that part working first.

Then you start on the next most complicated part and try to work your way through each part. As you're adding parts to the system you should keep testing to make sure that the already converted parts continue to work as well. In other words, don't break anything you've already done 🙂

You should make sure to keep a copy of the code at each step of the way and make notes about what you changed to make that version different from the one before. That way if/when you screw it up by making one too many changes you can always take a step back, restore the previous versioning have another go at it. I usually make a compressed file from the sketch and my text file of notes every time I make a change and get a passing test run.

Take it easy and don't try to bite off too much at one time.

I was kidnapped by mimes.
They did unspeakable things to me.


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SoundBeat
(@soundbeat)
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Joined: 3 weeks ago
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So the robot itself comes with two circuit boards. One being a servo controller board and the other being a BotBoarduino(basically the board that tells the servo controller what to do) https://www.robotshop.com/en/lynxmotion-botboarduino-robot-controller.html . What I want to do is test if the boards are communicating with each other to get the servo motors moving. Is there a way to test for it?

 


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Will
 Will
(@will)
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@soundbeat 

Since it was working before you broke the part and since it hasn't worked since you tried to "restore" the device, I would suggest that you remove all power from the device and sped a lot of time checking that the parts that are supposed to be connected ARE connected and parts that aren't connected are not, in fact, connected.

It seems like in 3 out of 4 times in problems like this, there is a wiring error (either open or short circuit). It may even be that the PCB has cracked and some of the traces are damaged. A couple of hours with a multimeter may solve your problem (or confirm the the board you have is toasted beyond repair 🙁 )

I was kidnapped by mimes.
They did unspeakable things to me.


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SoundBeat
(@soundbeat)
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Joined: 3 weeks ago
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I am confident to say that the wiring is correct and that the servo motors are fine. After a couple of hours, I know software is not an issue leaving me to believe that hardware is the only problem. I have checked the pins on the servo controller and they are all within voltage range of the servo motors. Is there a device you know or a method to ensure that both the servo controller and the Botboarduino are working fine in conjunction and not separately? I understand testing the actual parts themselves are important but how about their interaction with each other? Would you also know of a way to test the microcontroller on a circuit board with a multimeter? If so, how?


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Will
 Will
(@will)
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Posted by: @soundbeat

I understand testing the actual parts themselves are important but how about their interaction with each other? Would you also know of a way to test the microcontroller on a circuit board with a multimeter? If so, how?

You could test the micro controller by having it light up LEDs to provide visual proof that the pins are operational and can be turned on and off.

Usually you'd test the interaction of the two parts by operating the robot.

I was kidnapped by mimes.
They did unspeakable things to me.


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