Another new 2.4GHz system! - Page 13 - RC Groups
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Feb 09, 2009, 12:47 PM
have foam, will fly
waqa's Avatar
So, my parts list for the cable is:

1 - Level Shifter:
Assembled Shifter
Unassembled Kit

1 – PS2 keyboard connector with about 12 inches of cable still attached.

1 – RS-232 Male DB9 connector.
(You can harvest one from an old serial cable if you have one laying around)

I already covered the level shifter so will move on to the PS2 connector. The pin layout of the PS2 is the same as the 4 pin din layout needed for the radio but you’ll need to remove the little plastic key in the connector barrel. To do this take a small screwdriver or other implement and apply a little pressure to the key and it will break away easily. Try not to damage any pins but if you do bend a couple they can be bent back easily. What you’ll be left with is a 6 pin din, where the 2 top pins will now fit in the key of the transmitter. You can remove those pins if you want but I chose to leave mine in to provide some orientation protection.
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Feb 09, 2009, 12:57 PM
have foam, will fly
waqa's Avatar
Now that we have our PS2 connector cut away the keyboard or what ever is on the other end of the PS2 cable and identify what color wires go to the shield and 3 pins needed for the radio connection. I didn't color code or number the wires on the simple schematic as manufacturers don't all use the same pin-wire color scheme. Solder it up, provide some strain relief, and your ready to test it.

Note that the signal lines are all reversed, that is the radio transmit line is connected to the shifters 5v receive line, and so on. This is the nature of serial data transmission and can be confusing at times.

Since the radio is always transmitting channel data, when you plug the cable into the radio the receive LED (red) will light up. If it doesn't you've done something wrong.
Feb 09, 2009, 01:08 PM
have foam, will fly
waqa's Avatar
I chose to encase mine in hot glue for protection so I made a simple (and ugly) little foam mold and went at it. The result is a solid block and I can still see the LED's light up. Maybe someone knows a better way to do this.

That's it for my cable setup.

On a side note I think it is wise to remove the cable while your flying since any inadvertent signals may cause undesirable results.
Feb 09, 2009, 01:57 PM
R.I.P, Aardvark.
F-111 John's Avatar

The Trainer connector shown in this post: looks to me like an S-Video cable connector. You can buy S-Video cables in the electronics department of just about any *-mart store.

If it is indeed an S-Video connector, then no snipping of posts are required, as there would be with a PS-2 connector.
Feb 09, 2009, 02:06 PM
have foam, will fly
waqa's Avatar
Yes it is an s-video connector, a 4 pin mini din.
Feb 09, 2009, 05:01 PM
Registered User
keepitsimple's Avatar

Level Shifter

This is the levelshifter that I use at this moment.
The advantage is that I can lay the TX flat on its back.
I also tried another levelshifter with the electronics at the other end.
It works fine too.
Note the very old DB9-F mouse connector
Feb 09, 2009, 07:33 PM
I enjoy the voices
Lead Wings's Avatar

PPM Protocol

I have just re-visited this thread and it has got me thinking again.

I originally bought on of the HK 4 channels to see if I could use the 2.4 GHz RF module as a hack module for another radio (36 MHz JR 2610).

I was put off by the fact that the 2.4 GHz module is designed for a 5V + and the JR has a 10.7V +. That could be regulated down, but the other issue that my limited understanding hit was what about the PPM voltage.

I had read somewhere that the PPM voltage would be around1 V lower than the power voltage. And I guessed that while you could regulate the power voltage down, regulating a signal voltage like the PPM would result in bad things happening (images that were a cross from Ghost Busters and the Hindenburg sprang to mind).

When I opened my JR 2610 and measured the voltages to the RF board, I got 10.4 V for earth to power rail and then around 0.7 V for the PPM to earth.

Does anyone know if there is a protocol for PPM / what voltage for the PPM signal should be expected?

I assume this is an issue for something like the ASSAN module, which is generic and hence has to work with the different manufacturers – so are all the manufacturer’s PPM signals consistent in voltage? Assume this also applies to the buddy box/simulator out signals that are PPM? Or does the voltage not matter as it is getting amplified by the RF boards?

If the standard (?) PPM voltage for all radio sets is low enough, then maybe the 2.4 GHz RF unit from the HK/
Turborix could be used to 2.4 GHz hack unit for other radio sets, by the simple addition of a voltage regulator to supply 5V to the + ???
Feb 10, 2009, 04:15 AM
Registered User
Keep in mind that, in at least some radios I have played with, the main board is regulated down to 5v for the pots, electronics, etc, and thus you can tap 5v from there for the TX module if for some reason the TX is supplying higher than 5v to the native TX module. I am thinking the ppm signal sent is relative to the 5v board, IF you have a 5v board. A multimeter (wall, an O-scope, too) is a handy thing to have in your hand when trying to figure out this stuff.....

Hmmm. HK RF module in my Vex - could be really nice....


Feb 10, 2009, 05:58 AM
Registered User

HK-T4A has additional switch but not soldered. It must be rudder-elevator mix switch. Mod1 Mod2 converting jumper uses the channel five and three by shifting and changing the idle channel timing. You can use it as channel five. But it changes the throttle timing and receiver place (not channel 3, in this case u must use channel 2 for throttle).
Feb 10, 2009, 08:04 AM
R.I.P, Aardvark.
F-111 John's Avatar
When I opened my JR 2610 and measured the voltages to the RF board, I got 10.4 V for earth to power rail and then around 0.7 V for the PPM to earth.
I have no experience with your specific JR radio, but I do know from my electronics experience that you cannot use a DVM to measure the amplitude of pulses. You will be measuring the average voltage between the peaks and ground.

You need to use an oscilloscope to measure the pulse peaks. I have access to one at work, but most don't have them in their homes.

Somewhere upstream on this thread someone had a oscilloscope program for their PC that used the sound card as the input. That might be good enough for measuring the PPM signal in your radio to the RF board.
Feb 10, 2009, 02:17 PM
Registered User
Originally Posted by waqa
An Ipaq or any other PocketPC with a serial cable will do. I just happen to have a bunch of Ipaqs and am using it as a test bed for the software/hardware.

Ipaqs seem to be the most common PocketPC that come with serial cables. Most new PocketPCs come with only USB cables. All Dell Axim X3,X30,X50 and more have serial lines that use 5v logic so if you have one of those with a serial cable you won't need a level shifter like the what is needed for the Ipaq. Dell PDA serial cables are not common though and around $30 new.

I'll be posting the software today. I used my radio and Ipaq this weekend and it works great. I have everything done except sub-trims which I'll finish up today.
Technically I have the skills to build but not the programming capability. At the moment I could pick up a 3650 with USB cable only. Is it possibel to obtain a USB to serial cable or do the cradles on these have a seperate serial port for a serial cable? I've noticed while surfing Y cables? Would that work?
Feb 10, 2009, 09:22 PM
Registered User
kinkon's Avatar

First of all.. congratulations for this great job!

I see from your Mixer Screen that you "connect" the Pots to the 5th and 6th channel. By this you lose two Mixes and remains only one mix to use. My question: Is ther any other way to get the 5th and 6th channels operative?.

I bought the Tx and Rx from r2hobbies.


Feb 10, 2009, 09:55 PM
Registered User
kinkon's Avatar
[QUOTE=waqa].... Maybe someone knows a better way to do this.

Transparent heat shrink tube will do
Feb 11, 2009, 05:50 AM
Registered User

now the transmitter doesn't work


I've this Transmitter/receiver since 4 weeks and until yesterday it's works very well. Yesterday I was reprogramming this DR setting and when I have finished, I switched off and reconnected the transmitter and go to my model ( T-38 Trojan from Parkzone ). After switch on the transmitter and the model, the servos from canal 1-3 goes to the endpoint and do nothing, when I move the sticks on the transmitter , only canal 4 works.

Again on the computer I can see the same result in the T6config software, all the bares was on the endpoints and no movement ( Image1 ). In the meantime I've tried out a lot of possible configuration, I've reloaded the default values, I've deactivated all mixers, switches, DR without success. When I change the endpoints from 1 and 3 to 1 and 2, the bares becomes smaller and I can see a little changing when I move the sticks. Now in the configuration all endpoints are 100%, all SupTrims are 0, all switches and mixers are off, the mode is 2 and acro is selected.

Has anybody an idea, what could bee happen

Thank in advance

Last edited by wetskindiver; Feb 11, 2009 at 08:04 AM.
Feb 11, 2009, 10:46 AM
Registered User
MoFl's Avatar
Klaus, have a look at the potentiometers' solders and/or "plastic weldings" (plastic melted with a solderng iron to make a joint) in the joysticks' assembly.

There have been some reports of faults related to these in this thread and similar threads in other forums.

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