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I used to have a tiny helicopter that came with a funky 4 channel controller. I still have many of the pieces from the helicopter (windy day :( ) including the controller.

I have recently bought an Arduino Uno and built myself a robot and was wondering if it would be possible to use the controller? Is there any way I can work out the frequency and what would I need to plug into my Uno to do it?

UPDATED

Based on the [ON HOLD] feedback, I'm updating with a bit more detail

Internals http://www.subdimension.co.uk/files/images/RCHeloGuts.jpg

So I took the controller apart, clockwise from top-left:

  1. Receiver in helicopter (I assume based on proximity of aerial)
  2. Transmitter in controller (assumed from aerial embedded in board!)
  3. Unknown chip behind transmitter on back of board
  4. Flight control chip

All assumed from no knowledge at all though.

I reckon I could probably unsolder the little receiver but I'm pretty certain I don't have the skills to solder it back on to anything! I think I found a data sheet for it too.

What would be involved in extracting and reusing a chip like that?

Thanks

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    \$\begingroup\$ There are a handful of different 2.4 GHz chips in use, most with known data sheets. It is possible to reverse engineer the air protocols, and most of the ones of interest have been done. The usual tool is a USB logic analyzer to sniff the (typically SPI) traffic between the micro and the wireless chip. It can be a challenging project, so replacing the controller internals with an ATmega and an nRF24L01+, or buying an already reverse-engineering one should be considered, too. \$\endgroup\$ – Chris Stratton Nov 14 '15 at 2:56
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Your best chance is probably trying to salvage the receiver from the helicopter as well (assuming the receiver is a module or IC on its own and not integrated in one big integrated circuit that does everything). Then you could try to measure on the receiver side with a multimeter or oscilloscope whether something "interesting" happens if you move the controls on the remote. Also try to find a datasheet for the ICs (although the chances are not very high to find one because they are probably some ultra-low cost China parts)

Other than that I think it is very difficult and not worth the time to reverse the function of the controller (besides the possibility to learn something) because there are so many unknowns: 1. Which modulation is used? 2. Is the signal (the position of the controls) transmitted analog or digital

Even if you could find out the modulation and the protocol you still would have to build your own receiver, which is not an easy task.

If you just want to have a remote control you are better off by just using the "housing" and controls (I guess they are just some potentiometers) and ripping out all the old electronic and make your own with an arduino or similar and a little RF module that has a proper datasheet which only costs 1-5€.

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    \$\begingroup\$ Thanks Stefan. Since getting my Uno I've started looking at pretty much everything with "hmm, can I use any bits from that" eyes. It's helpful to know when it's more hassle than it's worth! The receiver is so small I've got little chance of getting it out! \$\endgroup\$ – MalphasWats Nov 13 '15 at 23:54
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    \$\begingroup\$ @MalphasWats In general, "hmm, can I use any bits from that" is not a particularly useful outlook on junk (for the last 20 years; especially for a beginner). More on that here and here. \$\endgroup\$ – Nick Alexeev Nov 14 '15 at 2:39
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    \$\begingroup\$ @NickAlexeev - the particular components in question are actually highly re-usable. There's a good chance someone in a place like rcgroups has already done the reverse engineering, meaning the transmitter can be used unmodified by sourcing an appropriate rf module (from ebay, a reciever or another transmitter) and working forward from published code to manage it. Even if not, the housing and sticks can be reused. \$\endgroup\$ – Chris Stratton Nov 14 '15 at 2:58

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