[Outofmydepth]

Hello everyone, just joined having bought my firstly RC model, a 1/8th scale tank for which I have also bought one of the open panzer boards. I will be using connectors 1-4 for esc's and 6-8 for the sound card and was wondering what connection I might use for a rotating 12 shot pyro unit? These are ignited electrically. Could I use the Aux socket for this? Many thanks for any assistance provided!

[LukeZ]

Hi and welcome to the forum! It would help to know what kind of signal your pyro unit requires, and how much current it draws. But yes, the Aux output is one possibility. Since you aren't using the onboard turret motor controllers for your turret, those can also be re-purposed as electronic switches (2 amps each). The smoker output can also be re-purposed as a switch if you aren't using a conventional smoker (up to 3 amps). Finally, there are general purpose outputs A & B that could be used, these are low-current outputs but you can attach a relay to them to drive larger loads.

Not many 1/8 scale tanks out there, and probably even fewer with pyro units. Feel free to post pictures of your project in the Show and Tell section, I'm sure a lot of people would be interested to see more about it.

[Outofmydepth]

Hi Luke,

thank you very much for answering my question and so quickly. There is a relay mounted in the tank and I suspect its purpose was to fire the pyros. With that in mind I have a few options. I had also thought that the motor outputs (A&B) were used even if using external motors (and somehow tied up two of the r/c outputs also) - I have read that section all over again and now have a much better understanding! I have never had any r/c model before of any type so learning from scratch (and the really basic stuff is the hardest to find answers to as everyone assumes you know this!). I will post some pictures etc, its not as big as the 1/6th models but still weighs in around 70kg. I only received it on Monday but I have been trying to plan ahead what I will need (and following the TCB for several months). Others have been helping with that on RCTankwarefare but essentially I will use the HobbyKing XCar 45A ESC's you recommend for the turret, gun elevation and to rotate pyro chamber and probably the Sabretooth serial motor controller, although I am a bit undecided whether two separate controllers may be better (if one should fail for example and it would be quite a saving). Thank you again (and I remain flabbergasted at you efforts).

[LukeZ]

Others have been helping with that on RCTankwarefare but essentially I will use the HobbyKing XCar 45A ESC's you recommend for the turret, gun elevation and to rotate pyro chamber and probably the Sabretooth serial motor controller, although I am a bit undecided whether two separate controllers may be better (if one should fail for example and it would be quite a saving).

In my personal view the dual motor serial controllers are superior in ever way to 2 ESCs, except for one, which is cost - the serial controllers are typically more expensive. However they take up far less space, require vastly simpler wiring, and have superior specifications in terms of whine and resolution although you may or may not notice those in a tank. I have never seen a serial controller fail if one has been sized correctly, although they also come with over-current protection so it is hard to kill them.

There is nothing wrong with using 2 ESCs but my impression is that most people who do, do so for the cost savings. Or else they are using brushless motors in which case the serial controllers are out.

Regardless of what you choose, you definitely need to have an idea of what your current draw will be to guide your decision.

If your pyro unit uses a relay, you may just be able to swap in one of the recommended relays from the Wiki (not all relays are the same, the TCB needs a 5 volt relay). Then attach it to IO Port A or B.

I was able to find your thread at RCTankWarfare for anyone who wants to follow along over there. I will post a few thoughts there as well, since this thread is primarily on the topic of your pyro unit.

[Outofmydepth]

Thank you for all these pointers Luke.

I understand about the relay and your references/advice means I am pretty comfortable with what I have to do in this regard now.

My OP boards arrived today and both are good (I thought I would have a spare in case I really enjoy myself and get another tank!). I have also been in touch with Thomas who has been very helpful with the sound card (Mini) and smoker (which I understand is controlled by the former).

So real progress is being made!

It was kind of you to search out my other post and your answer was very helpful.

Thanks again, Chris.

[Outofmydepth]

Hi - just giving the pyro mechanism some more attention/thought! It has occurred to me that I cannot really have the motor able to rotate the drum continually or without some limitations, either due to a fault or because it will not stop in time or loss of signal etc, otherwise numerous pyros could go off in quick succession (and probably blow the turret off!). I have been asking around if anyone knows more about these units (and how they are set up) but so far to no avail.

As regards control/limitations, would the OP board be able to put a limit on movement of the motor that rotates the drum so that it moves the drum 1/12th of the way around, fires a pyro and then stops? Then to repeat this you would need to reset the switch again. Or would the recoil output do something similar (as I presume this is a limited power supply just to create the recoil and then it is disconnected).

I have some photos of the unit that may better explain what I am dealing with!

Any suggestions/ideas very welcome!

[johnnyvd]

Yikes, that is one devious machine you got there!

I think you could use the recoil together with a one-way coupling and make a crank mechanism..
So a servo uses it stroke to move the Pyro mechanism 1/12 of a rotation (30 degrees)

Or you could consider a Geneva drive mechanism: https://en.wikipedia.org/wiki/Geneva_drive
Problem is to time the rotation.. That works way better with the servo..

You got a complete picture of the tank you have? I'm getting quite curious!

[LukeZ]

Very interesting device you have there. To answer your question, anything is possible but to create a timed movement you would need to modify the code slightly and recompile, it's not hard for someone familiar with the process but I don't recommend it for most people. I don't think it would be a good solution for you.

Johnny's idea of using the recoil servo is actually a good one but as he alludes to you will still need to create some kind of mechanical interface that moves the unit in only one direction while the servo does its thing. That may or may no be straightforward but for most people would be easier than recompiling code.

The best suggestion I can think of is to figure out what mechanism drove this thing in the first place? Obviously a great deal of thought and design work went into its construction, clearly it also had a control mechanism as well. Whatever that mechanism was would obviously be the best solution.

[Outofmydepth]

Thank you both for responding. Never heard of the Geneva Drive before, it would be a suitable system especially if building it from scratch.

I agree it would be most advantageous to know how it is supposed to operate! It is a beautifully engineered piece and therefore it stands to reason it must similarly have had a safe and reliable firing system. I have made other enquiries but as yet not found anyone familiar with the system. In its current form the drum is driven (rotated by a motor), which I think is the original set-up, but if I connect power to the motor it spins like any other and fairly quickly (although one would expect it to slow down when having to turn the drum). So I can only presume that something controlled the motor in such a way that it only engaged for a moment and moved the drum 30 degrees and stopped. I am just not aware of anything like that.

The next step is to connect the motor (without the pyros!) with an ESC and a switch and see what happens I guess.

I will take a couple of Pictures of the tank Johnny when I am next in the garage just to satisfy your curiosity!

Thank you both again, Chris.