Hacking X-Twin TX

[quax]

Hi all,

in an other thread:
X-Twin, Aeroace - post your mods, links etc.
http://www.rcgroups.com/forums/showthread.php?t=401484
the hacking of the TX comes up.

:D :cool: :D And the TX was cracked :D :cool: :D

Here the reference posts:
http://www.rcgroups.com/forums/showpost.php?p=4263247&postcount=244
http://www.rcgroups.com/forums/showpost.php?p=4266058&postcount=249
http://www.rcgroups.com/forums/showpost.php?p=4267638&postcount=251

:) I think, this is a topic for all DIY fanatics :)

There are a lot of options to realize, especially to eliminate the disadvantages of the original TX, e.g. BANG-BANG steering and only 7 step power control.

The X-Twin itself has a 16 step power control for each motor, including one step for power off.

If the X-Twin is used or only the RX, motors and lipo with an own plane-design, I expect a significant improvent in flight control, adding an own logic to the TX.

Quax

[quax]

I add some images of pulse packets for better understanding.

The first shows the channel position and the second the prop1 and prop2 codes with 2 bit checksum in the end.

Quax

[quax]

One solution can be found here:

http://www.rcgroups.com/forums/showpost.php?p=4313806&postcount=316

I think this topic is continued there.

Quax

[27MHz]

Hi Quax,

I've been eyeing this wonderful modification (http://home.versanet.de/~b-konze/xtwin/xufo_mod/xufo_mod_en.htm) of yours for a while now. I'm ready to buy an X-UFO radio and try to build the circuit that you've published (http://home.versanet.de/~b-konze/xtwin/xufo_mod/xufo_twin.jpg)... but I have a few questions. I'm very new to building circuitry, so please excuse me if I ask very naive questions:

1) I've found X-UFO radios in two frequencies (27.195 and 27.045 MHz)... neither of which is the same as the Aero Ace radio (http://www.rcgroups.com/forums/showpost.php?p=6175132&postcount=4) (27.145 MHz). Which of the two is the best for flying the Aero Ace? Do I need to find a new crystal to modify the radio to the same frequency as the biplane?

I've never played with an ATtiny2313 (or any other microprocessor) but am excited to give it a try. I've seen your recommendation for tools (http://www.rcgroups.com/forums/showpost.php?p=6462935&postcount=1490) here...
2a) the free IDE AVR Studio (http://www.atmel.com/forms/software_download.asp?fn=dl_aStudio4b460.exe), is it this item?

2b) I've seen your chip upload module (http://www.lancos.com/e2p/betterSTK200.gif) and it looks great, but what do you think of this ready-built one? It's only 4.90$ US + 4$ shipping... looks like I could save a little time... unless the Lancos board is really, really easy to build (I wouldn't mind saving a little time here).

2c) Futurlec also lists two different ATtiny2313 chips (http://www.futurlec.com/cgi-bin/search/search.cgi?search=attiny2313) in the 2$ US range... is one better than the other for this application?

2d) to get my feet wet... do you know of any very simple project I could build around an ATtiny2313? Maybe a light-chaser or traffic-light simultor or anything that uses simple components and can help me see that I've put the basic pieces together properly? Thanks.

3) Do you think this mod could be extended in the future when the 3-channel Silverlit planes come to market?

4) The small printed circuit board that you use in your realization (http://home.versanet.de/~b-konze/xtwin/xufo_mod/xufo_2313dil.brd)... how do I use that .brd file?

5) Is the X-UFO the best radio I can modify for the Aero Ace?... or is there an inexpensive "hobby grade" transmitter that I should consider instead?

Many thanks,
John

[quax]

Hi 27MHz,

lots of questions - I will do my very best :)

1)
The exact frequency doesn't matter. All around 27MHz ;) will work. The superregenerativ receiver "eats" all.

2)
2a)+2b) is ok.
2c) Take the ATTINY2313-20PI. The V-type is for low voltage use and has a lower working frequency.
2d) There are a lot sites in the web with examples. Here I found a tutorial and some more information: http://www.devicetools.com/Architecture/AVR/Tutorial/index.html

3)
I hope so and I can't await the delivery of that plane. I missed the elevator all the time and spend a lot of time, thinking about adding it to the X-Twin.

4)
If you know someone, who can make a PCB for little money, he also knows how to use this file. I myself use a perfboard (I hope this is the correct word for it) and wire my board.

5)
It's easy with the X-Ufo transmitter, because the needed part of the schematic is hacked. May be, that better transmitters are out there, but I don't know about them.
You need the PPM signal with TTL-level and a location, where you can switch the 27MHz ;) on and off. Means 100% modulation. Such tx should be usable.

Ciao
Quax

[27MHz]

Thank you Quax!

I'm busy digesting all of this great information and gathering the bits and pieces needed for this project. This is a very exciting sideline to the hobby for me... I never realized that it would lead me to this!

I've also had a chance to read about half of another Atmel thread in RCG (http://www.rcgroups.com/forums/showthread.php?t=630746) which is helping me.

I'll keep you posted on my progress.

Again, many thanks!
John

[27MHz]

Quax,

Do you have any photos of how you built the LancOS chip programmer (http://www.lancos.com/e2p/betterSTK200.gif)? I'm reading the schematic but have no idea where the ATtiny2313 would get attached for the upload.

Thanks,
John

[quax]

Hi John,

the connector J2 has the appropriate pin names to connect to the AVR.
You need MISO,MOSI,SCK,RES,VCC and GND. The AVR datasheet describes the controller pins with their alternate functions and there you can see the same naming MISO,MOSI,etc. The boards often have a connector on it that you can directly connect to J2.

Ciao
Bernhard