2LikesTransponder Design
04-26-2014, 06:38 AM
#181
Tech Initiate
04-28-2014, 05:19 AM
#182
Tech Initiate
Do you have a schematic? I can see a custom wound balun and I assume the capacitors are for filtering, but I don't see any amplification?
What sort of signal level do you get from yours? And how do you amplify it afterward? I am simply using opamps and a comparator now to turn the signal back into a digital pulse train.
My first attempt was a custom winding on a binocular core, this worked OK but wasn't amazing:
The newest one works much better and uses a Mini-Circuits transformer as a balun:
Unfortunately with a 470R resistor in the loop the second one is targeted at a 52R impedance system (the balun is 1:9) but that doesn't matter as I'm not attempting compatibility with AMB.
What sort of signal level do you get from yours? And how do you amplify it afterward? I am simply using opamps and a comparator now to turn the signal back into a digital pulse train.
My first attempt was a custom winding on a binocular core, this worked OK but wasn't amazing:
The newest one works much better and uses a Mini-Circuits transformer as a balun:
Unfortunately with a 470R resistor in the loop the second one is targeted at a 52R impedance system (the balun is 1:9) but that doesn't matter as I'm not attempting compatibility with AMB.
Thanks
07-25-2014, 04:17 AM
#183
Conversation continued here (from decoder thread):
Originally Posted by howardcano
I ran into a similar situation with my transponders. Here is the transponder thread:
Here is the particular post:
This post doesn't mention the "ghost numbers", although (if I recall correctly) the remedy described did fix this also.
The preamble is the same for "ID" and "status" messages. There are seven different "status" messages, with one sent every fourth transmission (with the "ID" message sent the other three transmissions).
Originally Posted by howardcano
I ran into a similar situation with my transponders. Here is the transponder thread:
Here is the particular post:
This post doesn't mention the "ghost numbers", although (if I recall correctly) the remedy described did fix this also.
Great information, but i have not find any status message on my AMBrc DP, how does the status message "preamble" look like, if any? I have a 200MHz recorder but it only record just enough time to get a id message in one frame (without triggers) so i have to try many times before i randomly get a message at the same time it records. And the antenna pickup is not great so the information is bad most of the time.
08-01-2014, 12:35 AM
#184
Tech Apprentice
Here is my source code for a transponder using an attiny25. So you can program your own with own numbers.
https://github.com/condac/openAST
It have the known issue to send "ghost numbers" and not working with patched decoders yet.
https://github.com/condac/openAST
It have the known issue to send "ghost numbers" and not working with patched decoders yet.
Last edited by condac; 08-02-2014 at 11:29 AM.
08-01-2014, 02:44 AM
#185
Tech Apprentice
It was not impossible once you understand its not a normal Convolutional code and no trellis diagram works at all
All credits to OM2KW for putting a lot of work into this.
Last edited by condac; 08-02-2014 at 11:28 AM.
08-01-2014, 03:00 AM
#186
Tech Apprentice
For people wanting to read their transponders and don't have a super expensive osciloscope, you can get a "Open Bench Logic Sniffer" google it and you will find local retailer.
putting it at a distance from the transponder with a cable as antenna and you can read the transponder, i use it at 100mhz to get length enough to record one message, and you have too try a lot of times to get the recording to start at the same time the transponder sends data but it will work in the end. You have to test for a good distance to get a signal that is not to powerful or to weak.
putting it at a distance from the transponder with a cable as antenna and you can read the transponder, i use it at 100mhz to get length enough to record one message, and you have too try a lot of times to get the recording to start at the same time the transponder sends data but it will work in the end. You have to test for a good distance to get a signal that is not to powerful or to weak.
08-01-2014, 03:04 AM
#187
Tech Apprentice
Am I right in saying that we can now build our own transponders based on Payalneg's hardware and your code?
All I can say is thank you very much for all your efforts. I'm sure there are a lot of people who appreciate what you have done.
All I can say is thank you very much for all your efforts. I'm sure there are a lot of people who appreciate what you have done.
08-01-2014, 03:14 AM
#188
Tech Apprentice
Payalneg's hardware needs some fixing, the ghost issue is probably due to bad antenna design in it. I have made a design using input for the Vcc to handle more than 5v also that is common in RC cars.
Hardware cost is about $8 at maximum and super common parts.
08-01-2014, 10:08 AM
#190
Tech Apprentice
08-02-2014, 06:40 AM
#191
Tech Apprentice
I've been watching this thread for about a year. I think it's really great of condac to open-source his code, and I hope this will lead to more improvements and possibly ready-made transponders for folks who aren't comfortable soldering and flashing.
However, I cannot overstate how amazing howardcano's work has been. None of this would have happened without his initial work, continued efforts, and advice to others. A simple "attaboy" doesn't seem sufficient for what he's achieved, but it's all I have to offer.
However, I cannot overstate how amazing howardcano's work has been. None of this would have happened without his initial work, continued efforts, and advice to others. A simple "attaboy" doesn't seem sufficient for what he's achieved, but it's all I have to offer.
08-02-2014, 10:33 AM
#192
Tech Initiate
Here is my source code for a transponder using an attiny25. So you can program your own with own numbers.
htp s:// gith ub. com/con dac/ope nAST
It have the known issue to send "ghost numbers" and not working with patched decoders yet.
(I cant add url so fix this for me someone)
htp s:// gith ub. com/con dac/ope nAST
It have the known issue to send "ghost numbers" and not working with patched decoders yet.
(I cant add url so fix this for me someone)
thanks.
08-02-2014, 11:24 AM
#193
Tech Apprentice
Latest commit on github now contains a C program and Java program to decode and encode.
To use the java program to encode run:
And the last lines you can paste in the asm file when you build your program and you have it ready to go.
To decode, input a binary string as argument (at least 12 char)
And give credit to OM2KW for cracking the FF sequence making this possible.
To use the java program to encode run:
Code:
cd encoderProgram/java/dist
java -jar rctcode.jar 3456789
encode2: 0101001000010111011001000101010000000000
encodeOut: 1110000111001011111111010010100100101000000100110001110100010011001111110000
ldi d1, 0xe1
ldi d2, 0xcb
ldi d3, 0xfd
ldi d4, 0x29
ldi d5, 0x28
ldi d6, 0x13
ldi d7, 0x1d
ldi d8, 0x13
ldi d9, 0x3f
To decode, input a binary string as argument (at least 12 char)
Code:
java -jar rctcode.jar 1110000111001011111111010010100100101000000100110001110100010011001111110000 known decoded: 01010010000101110110010001010100000000 known decoded int: 3456789
08-02-2014, 11:25 AM
#194
Tech Apprentice
08-02-2014, 12:47 PM
#195
Tech Initiate
perfect job !
condac, why you don't used the howard transponder design ?
condac, why you don't used the howard transponder design ?