Tcb partially resetting itself

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Sub
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Tcb partially resetting itself

Post by Sub »

Hi chaps.
A question for the open panzer tcb experts particularly Luke.
I have encountered an issue when setting up my tcb in my Tamiya king tiger, i am using an older DMD 01 for motor control and it works fine with the red wire disconected of course.
The turret stick controls turret rotation via the on board motor driver A and the barrell elevation is by servo pan set to 25 % speed the turret stick also controls the light fuctions of L1 and L2 and also machine gun with a 500 ms delay on turret move ment and all function as expected.
Now the issue....i am using the Aux 1 port via a 2 pos switch on the transmitter to provide 5v on / off to power a sound board if i switch on the aux port the board starts and plays BUT most times the TCB partially locks up..ie i loose turret rotation and barrel elevation and cannot turn the Aux port off via the switch you have to turn the battery off to stop it.
When you switch on the battery again still no barrel elevation or turret rotation..
I have connected the TCB into the computer on the OP config and performed a download from the TCB and on checking all the settings the turret rotation has re set itself back to rc input from motor driver a as has the barrel elevation from servo pan 25 % to rc input.
I re configure both back to servO pan and motor driver a and download and then disconnect and place back in the tank and all works as it should. This has happened several times so i have disconected the sound unit from Aux port 1.
Could it be there is some voltage spike at Aux port 1 when i swich it on causing the Tcb to revert back some of its settings to presumably default ones...and would installing a diode on the positive wire from the Aux port to the sound unit prevent any feedback the might be occuring.
In the meantime i will try connecting a small servo with a switch and seperate battery supply directly into the aux channel on the receiver to switch on the sound unit by passing the TCB.
Any thoughts ideas fixes welcome.
Regards Sub.
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LukeZ
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Re: Tcb partially resetting itself

Post by LukeZ »

There is perhaps more than one possible explanation for what you're experiencing but I think the most likely is that your sound board is drawing a bit too much current. Rather than a "spike" it is acting more like a "drain" and when you turn it on the processor on the TCB is blacking out.

If this is in fact the cause, rather than the complication of a switch and servo you could just get an inexpensive relay like this one, and connect it to one of the general purpose I/O Ports on the TCB (using a standard servo extension lead) and assign your 2 position switch to turn on/off that I/O port instead of the Aux output.

Out of curiosity, does your sound board require 5 volts specifically or can it operate at higher voltages?
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Re: Tcb partially resetting itself

Post by Sub »

Hi Luke.
Thanks for the fast response.
I was wondering if it could be what you have suggested re the drain also.
The board has à voltage of 3.7v to 5.5 volts max and will work quite happily on 4.8v i power two on 4.8v 2300 mah receiver pack on one of my other tanks without a TCB for hours with no problems i have checked the current draw with my multi meter and it draws 0.34 A at start up then drops to 0.25 whilst running.i am powereing the tank with a 7.2v 5300mah nimh.
Thanks again.
Regards sub.
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LukeZ
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Re: Tcb partially resetting itself

Post by LukeZ »

It's true ~0.3 Amps isn't much but you'd need more specialized equipment than a standard multi-meter to capture the short spike so no doubt in reality it is higher. It's possible you have something else going on too, the fact the TCB lost settings on reset is a little bit odd, but if the problem disappears when you don't try to run the sound card from the Aux output then I think that's really the most likely cause.

If your sound card was able to run on higher voltage the you could have used a different output on the TCB that can source much more current, but these other outputs provide full battery voltage (in your case 7.2 volts), so that won't work.

I think the relay is your best bet, thankfully they're very inexpensive and they plug right in.
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Re: Tcb partially resetting itself

Post by Sub »

Many thx for your explanation and time it is very much appreciated.
Regards Sub.
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Re: Tcb partially resetting itself

Post by Sub »

Did some more work on the TCB issue I have....
I located a 5volt relay in my electronics spares box and wired it into the Aux port so the TCB activates the relay and then wired the positive from a separate battery into the sound board I have and then switched the negative from the battery from the TCB through the relay and Hey presto the sound board fires up and no more TCB locking success.

I have another question Luke if I may.... I note that the OP ports A and B can be set to output and specifically to Pulse function which in the Wiki says will operate a button on an external device.
My question is I am using a small MP3 player module for sound and it has a button for changing tracks over ..could this op port when set to output and on pulse be used to effectively press the button on the player to change tracks over and if so how would I wire in the 3 core servo lead from the TCB onto the button legs to achieve this.( also would the OP port be set to high or low )
Sorry for all the questions but I am learning a lot about electronics this way and have six TCB's to install and this is my first attempt.
Kind Regards
Sub.
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LukeZ
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Re: Tcb partially resetting itself

Post by LukeZ »

Sub, yes that was the intent of the Pulse function in the first place. Another user has already done what you describe, you can read his thread here. He was using the MSM1 from ELV Elektronik, but other similar players should work the same way. Whether you set the output to default high or low depends on your MP3 player and what it considers to be a button press. Usually they will consider a signal to ground to be pressed, in which case you should set the A/B output to Default High.

Read that other thread and see if it answers your questions. That user is located in Brighton too so I don't know if that's close to where you are or not.
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Re: Tcb partially resetting itself

Post by Sub »

Hi Luke.
I have read the thread by Drew and unfortunately it does not help, it only reiterates what has been placed on the Wiki and what you have posted above in relation to the IO ports and its TCB setting.
The problem I have is that my sound board buttons have only two contacts at the bottom and when depressed simply make a circuit to activate their function so by just effectively shorting these contacts will activate the function.
There are 3 wires from the TCB pos. Neg and signal..i dont know which wires to attach to the 2 button contacts to make the TCB activate the button if indeed it is that simple if i manage to get this right i will be able to change sounds at will and alter the volume from the transmitter.
Could you provide any assistance as to which wires go where please ?.
Regards Sub.
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LukeZ
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Re: Tcb partially resetting itself

Post by LukeZ »

Every button has two contacts. One of them will be the signal to the computer on your sound board, the other side is just a constant voltage, probably ground but there's no way for me to know. When the button is pressed, the signal side of the button gets connected to the constant voltage side of the button. You'd have to determine what is what yourself with a multimeter and some knowledge of electronics.

For this to work, assuming it can, both the sound board and the TCB need to share a common ground connection. Your sound board also needs to operate at 5 volts, which you indicated it does (it does not need to be powered by the TCB however). You will connect the signal pin of the I/O A or B from the TCB to the "signal" side of the button on your sound card. The pos/neg pins of the I/O output will not be needed. If the button would normally connect to ground, then you would set the IO output to default high. When you trigger a pulse on that output the TCB will hold it momentarily to ground, which will emulate the behavior of the button on your sound card, which will then respond as if you had pressed a button.

To be honest this sort of connection scheme really requires you to have the ability to decipher and comprehend the electrical operation of your specific sound board. It's separate from anything to do with the TCB so you need to be your own support, I can't do it from here anyway. If you aren't clear on what you're doing it is certainly possible for you to damage one or both boards, in which case it may be wiser for you to forego this kind of arrangement.
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Re: Tcb partially resetting itself

Post by Sub »

Hi Luke.
Many many thanks for your comprehensive explanation, i did not think it would be as simple as i thought.
I will have a look at the sound board and might have to re think a mode of operation by passing the TCB for the sound change over and volume control ( its the same button ) which will be a lot more simple without any risk to the TCB.(prob a tiny micro switch and servo)
Kind regards
Sub.
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