Question on making a pistol tx

[losikid]

well i've been reading about people turning cheap china tx's to pistol grips, well i was going to do this but before i start to tear things up, i have a few questions. i only want three channels and i already have all that set up in a traxxas tq3. could i take out the chip out of the tx fit it into a tq3. then connect my steering wheel switch, throttle switch and my 3rd channel switch where the the ones on the tx is right now and do the same for the trim. For example i'll take the wires coming off the channel one switch on the tq3 and solder them to the wires that came off channel one on the tx. then the channel one trim wires on the tq3 will be soldered to the the channel one trim wires on the tx.

would this work or do i need to do something else, if you can't understand what i'm saying i'll draw up a diagram, here soon and post it

[Sicario666]

Sounds pretty complicated there... I'm interested to see if its actually possible. I wish I was of more assistance but I'll keep up on this thread to see if all worked out for you

[Galladon]

Losikid,
There is a thread on RC Groups mentioned in the other threads, where people have found a way to just install the 2.4 GHz module into an existing radio. The board used for this is pretty small (about a square inch). I would look into that if I were you, much easier than replacing the whole board.
Good luck!

[losikid]

i might think about that, but it will probably take some lookin to find it

[losikid]

this is kinda what i was thinking but do it with all the trims, and channels switchs, this is just a small example.

i just want to take the board out of the tq3 and put in the new board out of the tx and hook channel one wires together, etc, trims together,

i also heard that putting the 2.4 ghz module in there don't work to great

[clockworks]

Just so I understand what you are asking:

You've got a modified TQ3 which you want to convert to 2.4GHz? You don't need any more channels. Correct?

It's possible to convert some FM Txs using the RF PCB from one of the Chinese radios. To do this, you need to find where the signals from the main circuit (encoder) pass to the RF stage. This could be a bit tricky with an AM Tx, unless you can find a schematic, and someone who understands it.

It's much easier to replace the whole lot - main PCB and RF PCB. Depending on what 2.4GHz Tx you use as a donor, you'll have all the EPA, rate and trim options you will ever need, plus the option to use 3 extra channels in the future.

So yes, you can fit Chinese 2.4GHz electronics into a TQ3, and keep all your existing controls, assuming that the Chinese electronics physically fit inside the case. Looking at my spare TQ3, I think you will struggle with this. May need a bit of styrene work to get it inside.

Might be easier to start again, using the "HSP" pistol Tx for the case. The Chinese electronics are a perfect fit, and there's plenty of room inside for extra switches. You can get both Txs on eBay for about $45 for the pair.

As a bonus, you can keep using your TQ3 while you're building the new one.
Have a look at my build thread - just leave out the bits that you don't need, like 4ws. All you need is a single 3-position switch, plus the wheel and trigger. Should be a fairly straightforward build.

[losikid]

alright but when it comes to the boards and stuff i'm completely an idiot to it, but would it work if i just connected the tq3 wires to the new tx it would work right, i was thinking a hobbyking tx/rx, does anyone have the dimensions on the main chip

[clockworks]

The main PCB in the Hobbyking 6ch Tx is 45mm x 167mm. I think that the 4ch PCB is the same size, it just has less components fitted.
The 6ch Tx is computerised, the 4ch isn't. For the extra few $$, it's best to get the 6ch as the computer features, such as subtrim and EPA, are very useful.

Simple answer is, yes, it will work if you just connect your TQ3 controls to the Hobbyking PCB.

Obviously you need to connect them in the right place. You also need to connect the batteries and the power switch.
The other components, like the small RF module, antenna and computer interface, are all connected with wires. If you are careful, you can remove the whole lot without cutting these extra wires.

The circuit board modifications that I fitted to my Tx were only needed to allow the Tx to run on 4 cells. If you stick with 8 cells, you don't have to modify the board.

You might want to move the power/voltage warning LED from the main PCB so that you can see it from the front of the case - it's just 3 wires.

You can make the conversion as simple or as complicated as you like. At it's simplest, you just have to solder 11 wires - 3 for each channel plus the 2 power wires.

[meao]

I think that would be easier and cheaper just buying one of these:

http://r2hobbies.com/proddetail.php?prod=rcps61208

I emailed them to ask about the 3rd channel, and they have told me that is a 3 position channel.

Assuming that you only need 3 channels.

[clockworks]

Originally Posted by meao

I think that would be easier and cheaper just buying one of these:

http://r2hobbies.com/proddetail.php?prod=rcps61208

I emailed them to ask about the 3rd channel, and they have told me that is a 3 position channel.

Assuming that you only need 3 channels.

Wow - that's a real bargain. Like you say, much easier if you only need 3 channels.
Out of stock at the moment, though.

[losikid]

i like how the tq fits in my hand, so i'll probably stick with a custom build, also would a 3s lipo work as a battery for the controller,

[clockworks]

Originally Posted by losikid

i like how the tq fits in my hand, so i'll probably stick with a custom build, also would a 3s lipo work as a battery for the controller,

A 3s Lipo will work fine. The Tx drops the battery voltage down to 5v as soon as it hits the PCB - everything works off 5v. For this reason, a 2s Lipo should be OK, too.

You may find that the low voltage warning LED on the Chinese Tx doesn't work properly if you use a 3s or 2s LiPo, so it might be a good idea to fit an extra voltage monitor, directly on the battery. There are plenty of these available for RC plane battery packs. Have a look on eBay or at your LHS.