I can tell you that the Aurora 9 has a 23ms frame rate which most of the newer DSM2/DSMX receivers don't like. They will only work properly with a frame rate of no longer than 22ms. One exception I know of is the AR7000. Spektrum modules will transmit packets based on the frame rate of the TX. If the light is on solid in the module, then it's transmitting packets. If its out, either the power supply connections are wrong, the number of PPM channels is outside the allowable range or the polarity of the PPM signal is backwards. Try switching your TX to PPM+ or PPM-.

When you go to bind, the fast blinking receiver LED will go out if it receives valid bind packets. If it does not come on solid after a few seconds, then the RX is not able to lock onto the packets from the TX, most likely because the frame rate of the TX is too long. I have found that 22ms is about the longest frame the newest receivers will work with.

On my module that I attempted the module would power on but not go into bind mode. I wasn't ever even able to try to get a receiver to bind. It sounds like the frame rate is important but perhaps that isn't what was wrong with my setup.

Interested to hear more from jtaylor...

I just got the module yesterday, so I'll hook it up to some test equipment next week.

Hopefully it's not a frame rate issue, but wouldn't that be the case with everybody else's older modified modules?

I think the frame rate issue affects the receiver. The problem I had was with the module. The module powered but wouldn't go into bind mode.

Originally Posted by hammer22

I can tell you that the Aurora 9 has a 23ms frame rate which most of the newer DSM2/DSMX receivers don't like. They will only work properly with a frame rate of no longer than 22ms. One exception I know of is the AR7000. Spektrum modules will transmit packets based on the frame rate of the TX. If the light is on solid in the module, then it's transmitting packets. If its out, either the power supply connections are wrong, the number of PPM channels is outside the allowable range or the polarity of the PPM signal is backwards. Try switching your TX to PPM+ or PPM-.

When you go to bind, the fast blinking receiver LED will go out if it receives valid bind packets. If it does not come on solid after a few seconds, then the RX is not able to lock onto the packets from the TX, most likely because the frame rate of the TX is too long. I have found that 22ms is about the longest frame the newest receivers will work with.

So how did you fix this on your module?

I'll trade you a nib dm8 for one of yours

Do you have any good links to the relevant docs on the spektrum/a9 protocols/interfaces? An ICD would be nice, but that's probably asking too much from these companies.

I haven't had a chance to look at the module yet. I've been busy diagnosing a transmit antenna problem on a billion dollar satellite for the last week or so. Lots of staring at spec analyzer recordings... (16h worth) I'm losing serious brain cells on this one!

I originally was using the start of the PPM frame as a timing reference. The same 16 bit timer that was timing the PPM pulses was also being used to trigger some key events like packet transmissions via a 16 bit capture compare module. The timer was being reset to zero at the start of every PPM frame. As the PPM frame got longer, so did the interval between packet transmissions. When the frame rate got above 22ms, the Spektrum receivers would stop working.

I fixed it by allowing the 16 bit timer to free run and instead of using time values referenced against zero for the Capture/compare module, I add a time offset to the capture/compare module to set them up for the next event trigger. This method takes advantage of the wrap around that happens when you add two 16 bit values together using a 16bit register for the results. The PPM pulse timing math is not bothered by the wrap around either. So now the packets are sent at a nice steady 21ms rate and the PPM frame rate can be anywhere up to the maximum value of the16 bit timer (65535 = 32.768ms).

I'll have to think about the DM8 trade though.

There is very little about the Spektrum DSM2 protocol available on the web except for what I posted in the DIY electronics forum a year+ ago. There is even less on DSMX. DSMX is basically DSM2 but using 23 channels instead of 2.

Sorry, but I don't know anything about the Hitec A9 protocol.

Hi everyone. Since I can't find any DM8 around, can this mod be used on the "OrangeRX DSMX/DSM2 2.4GHz Transmitter Module (Futaba Compatible)" or similar module? Has anyone tried it yet?

I haven't read the thread completely so I'm sorry if this has been covered already!

Hello,

at Futaba slot it works fine.
i think the mod work.
the layout have no place for the connector from the A9
you must take a adapter to use it outside from A9

bye Joachim

Has anyone tried one of these yet??
Price is right and saw in their comment section someone said it will work...
May order one and try it..

Hello,

http://www.rcgroups.com/forums/showp...&postcount=278

bye Joachim

Originally Posted by rlongfel

Has anyone tried one of these yet??
Price is right and saw in their comment section someone said it will work...
May order one and try it..

DOH! I must have been asleep. Needless to say I ordered one with two R615 Orange recievers. I will let everyone know how it works out. I'm pretty good at rigging things. Making the A9 antenna easily removable is first on the list.

Will this mod void the warranty?

Depends on which product you are concerned with and how you do it.
-If you fry your tx because you didn't do the mod correctly it could void your warranty.
-If you modify the tx, you could void your warranty.
-If you are successful with the mod and don't modify the tx, then Hitec has been great about warranty support.
-The warranty on the module is likely to be void since most of these mods require modifying the module.

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Just wanted to say thanks to all of you that worked this DIY project to a success. I just received a DM8 module yesterday (shipped promptly from Esprit), picked up the components and soldered my first perfbord circuit. All systems go. I was able to successfully bind and fly my mSr. Thanks guys!

Cubbuddy, that is the right module (just packaged with a Rx).