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Old Jan 25, 2009, 02:05 AM
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Its the same protocol. The 4th wire is just for the red LED on the front of the LP5DSM near the dip switches.
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Old Jan 25, 2009, 05:52 AM
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Thank you Steve! I see now that it's the same exact PCB in your photos and mine.

Now all I need is a 125kbaud USB port, and I can start hacking away.

Ari.
Old Feb 11, 2009, 03:38 AM
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I bought an FTDI USB<->serial adapter that can do 125k baud and I can read serial data as Steve describes from my Vapor RTF TX. This TX activates binding mode if you turn it on while pressing in the left stick. I find that in this case the first few hundred packets go out with a different header.

Normally, first two bytes in a packet are 00 00. With the stick pushed in, they are 80 00.

Ari.
Old Feb 11, 2009, 05:19 PM
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The transmitter is in bind mode every time its turned on. Pushing the stick in may change some data but should have nothing to do with binding as that is handled entirely by the 2.4ghz module.
Old Feb 11, 2009, 06:01 PM
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There are two versions out--one that binds every time you turn it on, the other doesn't; the one I tested is the second kind:
Quote:
Originally Posted by http://www.horizonhobby.com/Products/Support.aspx?ProdID=PKZ3300

Vapor RTF sets using AutoBind (LED on aircraft receiver/ESC unit and transmitter will blink immediately upon powering on):

1. Ensure flight battery is fully charged and transmitter AA batteries have adequate power.
2. Plug the flight battery into the receiver/ESC unit and the LED will begin blinking.
3. Within 5 seconds of powering on the Vapor receiver/ESC, power on the Vapor RTF transmitter (LED on the transmitter will begin blinking) and the bind process will complete within 15 seconds.

Vapor RTF sets without AutoBind (LED on receiver/ESC unit will begin blinking after 5 seconds of being powered on. LED on transmitter remains solid when powered on):

1. Ensure flight battery is fully charged and transmitter AA batteries have adequate power.
2. Plug the flight battery into the receiver/ESC unit. The LED on the receiver/ESC unit will begin blinking after 5 seconds.
3. Once the LED on the receiver/ESC unit is blinking, push IN on the left control stick while powering on the transmitter. Release the left stick once the transmitter is powered on. The transmitter will beep, signifying the transmitter is in bind mode. The bind process will complete within 15 seconds.
Last edited by iter; Feb 11, 2009 at 06:09 PM.
Old Feb 11, 2009, 06:08 PM
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The TX I have transmits 6 controllable channels. It has pushbuttons under its sticks. If you press the right stick, the TX toggles channel 5 from a medium-low to a medium-high state. If you press on the left stick, it brings channel 6 high and keep it high as long as you keep pushing on the button. I don't have the actual m=numbers it sends out here. I plan to post them when I get home tonight.

Interestingly enough, when you power on the TX with the left stick depressed and it comes up in binding mode, it sends a low value for channel 6, as if you hadn't pressed the stick.

Ari.
Old Feb 11, 2009, 11:40 PM
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Ahh, thanks for the update. While the left stick binding is a nice feature the autobind sure made it easy to use the tx module with other stuff.
Old Feb 12, 2009, 02:24 AM
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I expect that left-stick binding works with other DSM2 receivers as well although I have not tried it. I also expect that if I send a 80 00 header to my RF board at startup (or ever?) it will go into binding mode. I won't have time to test this hunch until the weekend.

Steve, I have a question for you. Both my RS232 USB dongle and my uC run at 5v. The RF device uses 3.3v. I imagine that if I feed 5v to the RF control line I may fry the RF device. How can I prevent that? Is there a resistor I can put between them to limit the voltage?

Ari.
Old Feb 12, 2009, 03:49 AM
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Here are the numbers I measure from my RTF TX:
Code:
# function   low   centr high

0 throttle   00AA     *  034F
1 aileron    04AA  05F7  0740
2 elevator   08AA  0A4F  0B54
3 rudder     0CAA  0DFF  0F54
4 r pushbtn  10AA    **  1354
5 l pushbtn  14AA   ***  1754
Notes:
* non-centering throttle stick
** toggles h-l or l-h on every press
*** low normally; high when depressed

This TX seems to limit values it sends out to (decimal) 170..852, with 511 as neutral. Pushbuttons give the same range as full stick swings.

I measure about 45 (14-byte) packets a second.

Ari.
Old Jun 25, 2009, 04:00 PM
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Steve, thank you for sharing your reverse-engineering. I successfully fly a number of Vapor brick models using a TX I build following your findings.

https://www.rcgroups.com/forums/show....php?t=1069598
https://www.rcgroups.com/forums/show....php?t=1069110

Ari.
Old Jun 29, 2009, 07:24 PM
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I notice that the RX responds only if I send exactly 6 channels. If I send any other number, it behaves as if it can't hear a TX at all.

Many other DSM2 transmitters have more than 6 channels, like DX7, X9303, etc. I wonder how they can work with this receiver.

Ari.
Old Jul 09, 2009, 12:45 PM
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Quote:
Originally Posted by iter
I notice that the RX responds only if I send exactly 6 channels. If I send any other number, it behaves as if it can't hear a TX at all.

Many other DSM2 transmitters have more than 6 channels, like DX7, X9303, etc. I wonder how they can work with this receiver.

Ari.
Well, they have to talk both ways to bind, maybe the Rx tells the Tx how many channels it wants and the Tx just sends that many.
Old Sep 05, 2009, 08:39 PM
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Guys can any of the movements on the DSM2 transmitters be reversed? I'm tring to reverse the ailerons but I don't know how if its possible?
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Old Sep 06, 2009, 12:38 AM
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Quote:
Originally Posted by brad65ford
Guys can any of the movements on the DSM2 transmitters be reversed? I'm tring to reverse the ailerons but I don't know how if its possible?
It's easy if you have one of the computer TX's like a DX6i or DX7. With an LP5DSM, it might be a little more tricky - there's a set of DIP switches under the front panel with the LED.

Which TX are you using?
Old Sep 06, 2009, 12:41 AM
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Quote:
Originally Posted by brad65ford
Guys can any of the movements on the DSM2 transmitters be reversed? I'm tring to reverse the ailerons but I don't know how if its possible?
If it IS an LP5DSM, then you'll find a listing of what the switches are SUPPOSED to be in this thread: https://www.rcgroups.com/forums/showthread.php?t=611167


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