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Aug 26, 2009, 12:59 PM
Aircraft re-kitter
ergocentric's Avatar
open collector maybe?

try a 10k resistor to Vcc
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Aug 26, 2009, 02:13 PM
Registered User
meteor's Avatar
What would that look like in a simple circuit diagram?

I'm guessing you mean: +5V -- 10K -- PPM input on FSK module -- PPM output on radio?

Essentially, when the radio pulls the line low, the module sees low as well, thus making a 5V "negative shift" pulse train. Correct?



Thanks!


Quote:
Originally Posted by ergocentric
open collector maybe?

try a 10k resistor to Vcc
Aug 26, 2009, 03:18 PM
Aircraft re-kitter
ergocentric's Avatar
Quote:
Originally Posted by meteor
What would that look like in a simple circuit diagram?

I'm guessing you mean: +5V -- 10K -- PPM input on FSK module -- PPM output on radio?

Essentially, when the radio pulls the line low, the module sees low as well, thus making a 5V "negative shift" pulse train. Correct?



Thanks!
Tie the PPM line to Vcc with a 10k resistor, then scope it.
Open collector means it can only pull a signal down and you must provide pull-up at the other end, works better on long wires.
Aug 26, 2009, 09:08 PM
Registered User
meteor's Avatar

It Works! :)


Wahoo! It Works!

Super simple. Just put a 10K from the 7805 +5V to the FSK module PPM input, and attach the Futaba PPM output (module pin 1) to the low side. (the photo is just a rough hack, but you could put the 10k across neatly the posts that tie the boards together...)


Now to fix it all up!


Have fun!



Quote:
Originally Posted by meteor
What would that look like in a simple circuit diagram?

I'm guessing you mean: +5V -- 10K -- PPM input on FSK module -- PPM output on radio?

Essentially, when the radio pulls the line low, the module sees low as well, thus making a 5V "negative shift" pulse train. Correct?



Thanks!
Last edited by meteor; Aug 27, 2009 at 01:32 PM.
Aug 26, 2009, 09:41 PM
Aircraft re-kitter
ergocentric's Avatar
Excellent work, I was thinking about using one just like it, but not modular with my corona 2.4 for boating.

I got it in a trade with some other stuff.
Sep 07, 2009, 07:35 PM
Registered User
Quote:
Originally Posted by ergocentric
Now I need to troubleshoot the voltage fluctuations


http://www.youtube.com/watch?v=guRmRTtsxF4
Any update on this issue ?

thanks
Sep 08, 2009, 10:02 PM
Registered User
I have an older Futaba "Magnum Jr" AM Pistol grip radio I would like to convert to 2.4. Has anyone had success with an AM radio or strictly PPM FM?


Thanks
-CaKe
Sep 09, 2009, 02:41 AM
Registered User
Quote:
Originally Posted by beefcake
I have an older Futaba "Magnum Jr" AM Pistol grip radio I would like to convert to 2.4. Has anyone had success with an AM radio or strictly PPM FM?


Thanks
-CaKe
It's probably better to replace all the electronics, rather than just the RF board. It'll work fine, as long as the new main PCB fits in the pistolgrip case.
Sep 09, 2009, 07:28 AM
Registered User

12 V or 5V


Can the hobby king take 12V or only 5V

I am thinking of using my friends old hobbyking 2.4 "daughterboard TX " and implant it into my Futaba

Cheers
Sep 09, 2009, 07:46 AM
Registered User
Quote:
Originally Posted by BenziT
Can the hobby king take 12V or only 5V

I am thinking of using my friends old hobbyking 2.4 "daughterboard TX " and implant it into my Futaba

Cheers
The Hobbyking uses 8 AA cells, so it's designed to run on 12V. There are 2 regulators on the main PCB that take the 12V supply from the battery box and provide a 5v supplies to all the electronics. There is one regulator for the main PCB, the other is for the RF board.

If you bypass the regulators, it works fine on 4 AA rechargeable cells.

So, if you use all the electronics, you have the option to use 4 cells or 8 cells. If you just want to use the RF board to modify an existing Tx, you must use 5v.
Sep 09, 2009, 07:50 AM
Registered User
meteor's Avatar
AM/FM is not relevant in this case, since you're dealing with the basic PPM signal before it reaches the RF stage. FYI, the 5U I tested it on was AM.

The tricky part with your radio will be finding the PPM signal. It probably exists as an output on the encoder IC.

Here's an article about converting an Attack 4, which is of a similar vintage (he also talks about a 2PL, which is a lot newer...): http://blog.quantifly.com/


Good Luck!

Quote:
Originally Posted by beefcake
I have an older Futaba "Magnum Jr" AM Pistol grip radio I would like to convert to 2.4. Has anyone had success with an AM radio or strictly PPM FM?


Thanks
-CaKe
Sep 09, 2009, 12:21 PM
Registered User
MoFl's Avatar
Quote:
Originally Posted by BenziT
Can the hobby king take 12V or only 5V

I am thinking of using my friends old hobbyking 2.4 "daughterboard TX " and implant it into my Futaba

Cheers
The hobbyking module can take 12 V, as it includes a board with a 5 V regulator, appart from the RF board.

The RF board at HK 4ch & 6 ch systems is designed for 5V. Maybe it can admit some margin arround 5 V because it has a 3.3 V regulator at the input, but probably not much above 5 V because it's a SMD regulator without heatsink (schematics of the RF board here).

Photos of the RF board and the module (RFboard + regulator-bind button board) here.
Sep 09, 2009, 02:51 PM
Registered User
Thanks !
Sep 18, 2009, 02:52 PM
Aircraft re-kitter
ergocentric's Avatar
I have a couple of JR beat2 AM two channel 27MHz transmitters.
Its on my to-do list
First comes the honeydo list
(when the wife sez honey, do this ...)

I also have the same radio in PCM, so it will help with the dissection and annotation (same radio, different transmitter)
Sep 18, 2009, 03:06 PM
Aircraft re-kitter
ergocentric's Avatar
Quote:
Originally Posted by beefcake
I have an older Futaba "Magnum Jr" AM Pistol grip radio I would like to convert to 2.4. Has anyone had success with an AM radio or strictly PPM FM?


Thanks
-CaKe
even better, he converts a Futaba 2PL to corona 2.4:

http://blog.quantifly.com/?p=12

seems to be offline

http://web.archive.org/web/200906150...ifly.com/?p=13
Last edited by ergocentric; Jul 17, 2011 at 05:42 PM.


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