Is it possible to change the control frequency?

9 posts / 0 new
Last post
NakedBoB
NakedBoB's picture
Is it possible to change the control frequency?

A friend of mine got the Flytech Dragonfly last week.  After seeing his in action, me and three of my pals decided to get our own from Radioshack. After they charged we all decided to go out and give 'em a test run. Well...it turns out that they only use two frequencies (the blue dragonfly 27Mhz and green dragonfly 49Mhz.) This means that you can't have two blue dragonflies (or two green ones) flying at the same time. Bummer.

Maybe this question is for the hacking thread, but has anyone attempted to adjust/change the control frequency?You don't know how awesome it'd be to have dragonfly races (battles?) Hopefully it's not impossible. I'm willing to take a blade to my Dragonfly if there's even a smidgen of chance that it'll work.

Thanks for listenin'!

-Naked BoB 

dsetzer
dsetzer's picture

A friend over at the RCGroups.com forums knifed into his (and then glued it back together and it works!)... anyway, you can checkout the pics at:

http://www.mydragonfly.info/photos/default.asp?CatId=2&CatName=DragonFly+Innards

 -Doug

NakedBoB
NakedBoB's picture

Neato! At least it's a start. Now to take apart the controller and see what's in that thing.

-Naked BoB 

dsetzer
dsetzer's picture

I asked around a little and no one has yet.  I might consider it if I get bored in the next coupla days.

 -Doug / http://www.mydragonfly.info/

Neoaikon
Neoaikon's picture

Inside the controller, there should be a Tx chip and inside the dragonfly there should be a Rx chip. You could bypass these chips and lead them to a chip like the qkits.com TX433 and RX433. these operate on 433Mhz, which may or may not be illegal to use for hobby purposes, in ohio at least its legal as far as I know. The only considerations are powering the chips, since the 27mhz chips probably use lower voltage, but that'd depend on the chip. Does anyone know what the part numbers are on the chips within the controller and dragonfly?

A replacement should be possible, i got my dragonfly cheap at bestbuy, so maybe I'll go back and get another one to mess with. THe only consideration one must have with this is antenna tuning, the dragonfly should be fine as is, but the controller antenna would more than likely need to be replaced with some thin copper magnet wire of a certian length.

Nocturnal
Nocturnal's picture

You may find these of interest

http://evosapien.com/robosapien-hack/...

If you find a datasheet for the FDLabs board, I'd be interested in seeing it. You may also find some of the other threads interesting. 

 

Neoaikon
Neoaikon's picture

What we need is the name of the company that makes the tx/rx chip, or if it uses a tuning coil and just pulses the signal down that. That could be the case, but to be sure we'd need to verify every IC on the controller and d/f to find out what each one does. 

MrScott
MrScott's picture

A complete system description would be one to figure out how it's done.

A more directed approach might be to compare controllers/receivers of the two available frequencies, and find out how they differ.

If it's a chip, or a pinout tie-up/down, that would lead your search to that particular part number.

Wouldn't it be great to find out that there was a set of pins that you tied to set the frequency, and that more than the two advertised frequencies were available?  I wouldn't count on it, though. Most of these sorts of toys only seem to be available on the same two frequencies. If the chipsets were easily extendable to more, manufacturers would be using more varied frequencies. 

Neoaikon
Neoaikon's picture

well its not so much what they can give us, more like what they're willing to pay for. There are actually subsets to the 27mhz and 47mhz frequencies, if they wanted they could only manufacture 27mhz ones and just use a few subsets of it, i'm sure if there's future models they'll probably have this capability, but replacement is still a real option. I'm sure even if the devices only have a tx/rx system for 27, and 47mhz, there should be similar chips with similar pinouts.

If not however it still shouldn't be hard to mount another chip, providing we can power the chip and hook up the input to whereever the devices are generating the signal on the board, and we should be able to broadcast on that frequency instead.

The power requirements for the tx/rx are probably pretty low, i know the 27mhz tx/rx chips i have use a little more than 1.5v in my circuits, but my 433mhz chips have a power range from 5-10v, needing at least 5 to function at all. If the power requirements aren't enough to power the chip we're mounting, then we need to provide it with power as well.

That shouldn't be hard to do, the only thing we'd need to know are if the devices use a chip, or a tuning coil. if it uses a chip we have to make sure to disconnect it from the circuit, since it'll be a drain, whereas the coil isn't really a problem.