3LikesTransponder Design
08-18-2015 | 05:55 AM
#286
Tech Apprentice
Joined: Jul 2014
Posts: 86
From: Sweden
Sorry for not replying to any messages, But I have actually been outdoor the entire summer and used my rc cars....
I can't help people trying to get this working for other systems than RC, i have published everything we have found and figure out about the RC3 and its not even working for RC3 in all cases. But I'm not saying its impossible to use but for example you can start by finding out the preamble of the other systems and check if they even work on the same frequency.
I can't help people trying to get this working for other systems than RC, i have published everything we have found and figure out about the RC3 and its not even working for RC3 in all cases. But I'm not saying its impossible to use but for example you can start by finding out the preamble of the other systems and check if they even work on the same frequency.
08-21-2015 | 05:04 AM
#287
Tech Rookie
Joined: Dec 2014
Posts: 14
Sorry for not replying to any messages, But I have actually been outdoor the entire summer and used my rc cars....
I can't help people trying to get this working for other systems than RC, i have published everything we have found and figure out about the RC3 and its not even working for RC3 in all cases. But I'm not saying its impossible to use but for example you can start by finding out the preamble of the other systems and check if they even work on the same frequency.
I can't help people trying to get this working for other systems than RC, i have published everything we have found and figure out about the RC3 and its not even working for RC3 in all cases. But I'm not saying its impossible to use but for example you can start by finding out the preamble of the other systems and check if they even work on the same frequency.
1) RCtcode generator codes, binary code encode2: xxxxxxxxxxxxxxxxxxxx, that code is ????
2) The encodeOut: xxxxxxxxxxxxxxxxxxxxxxxxxxxxx is the number of transponder with flames header and end ?. This code is sent to the decoder in the RC3
3) From what I experienced, the RC3 with this code RF plot has a number of phase reversals which is not constant, it changes with the number of decoder?
4) This works in the AMB decoder?
5) Pro TranX my transponder RF signal is composed of 22 RF packages (each package is formed with each investment phase), and that amount is constant regardless of the number of transponder. What changes it is the length in time of each packet in specific values, which you describe in the next section.
08-21-2015 | 05:19 AM
#288
Tech Rookie
Joined: Dec 2014
Posts: 14
Description of the signal generated by the transponder TranX Pro:
1) Each communication frame 22 is formed by RF packets, each packet is formed by phase inversion result of the binary state of the bit output
2) Cualqueir number 18 Transponder TranXPro tested, always generate a frame with 22 packets and what changes are the lengths of the packages, in particular values.
3) The length of the first and last packet of each frame can have a variable length code not affect
4) the second and third package, as the package size 20 did not fit, are fixed regardless of the number of transponder
5) packages ranging from 4 to 19 inclusive, change their sizes in concrete numbers. Possible sizes are 4.4us, 6.6us, 8.8us and 11US.
6) The package 3 has a size of 15.6us and package 21 has a size of 13.2us
7) The carrier frequency is at 3.579MHz
1) Each communication frame 22 is formed by RF packets, each packet is formed by phase inversion result of the binary state of the bit output
2) Cualqueir number 18 Transponder TranXPro tested, always generate a frame with 22 packets and what changes are the lengths of the packages, in particular values.
3) The length of the first and last packet of each frame can have a variable length code not affect
4) the second and third package, as the package size 20 did not fit, are fixed regardless of the number of transponder
5) packages ranging from 4 to 19 inclusive, change their sizes in concrete numbers. Possible sizes are 4.4us, 6.6us, 8.8us and 11US.
6) The package 3 has a size of 15.6us and package 21 has a size of 13.2us
7) The carrier frequency is at 3.579MHz
11-12-2015 | 01:22 PM
#289
Tech Initiate
Joined: Apr 2013
Posts: 46
I think the design is now stable enough to provide a schematic:
As you can see, there's not much to it! A 74AC86 exclusive-OR gate serves as the oscillator, changes the carrier phase under control of the microprocessor, and provides high output current to the tank circuit. (I may change to the 74HC86 to reduce high-frequency emissions, but that will require increasing R4 and R5 to reduce the output current, giving less field strength. Right now the field strength is just about the same as my AMB and MRT transponders.)
One interesting thing that I mentioned previously about the design is that the tank is driven differentially (bridge drive), which substantially reduces the second harmonic level in the output spectrum. This could help with meeting emissions requirements.
The values of CT1 and CT2 might have to be changed to match whatever tank inductor you use. My original perfboard prototype used 16 turns of 30 gauge Kynar (wire-wrap) wire, while the PC board has 20 turns of traces (10 on each side). The ratio of the two capacitors will set the tank Q (CT1 larger gives higher Q), while the series combination of CT1 and CT2 sets the resonant frequency.
R1 was originally a limiting resistor for the shunt regulator inside the intended microprocessor, the PIC12HV609. It is shown as a diode because I have been using PIC12F508 microprocessors left over from another project. The diode drops the input voltage by about 0.6V to keep the 12F508 happy (it has a maximum operating voltage of 5.5V), and as a bonus protects the transponder from reverse polarity. Using the 12F508 (or almost any 12F series device other than the 12HV609) means the supply voltage to the transponder is restricted to 6.1V maximum. That's okay for virtually all BEC circuits, but is not compatible with a 5-cell NiMH or 2-cell LiFe battery. I stopped using receiver batteries a long time ago! Adding a separate Zener diode would let the transponder operate from the same large voltage range as the PIC12HV609 permits.
I am considering changing to the PIC12F683 for its larger memory and EEPROM.
The 47uF cap is probably not necessary for use with ESCs having linear BECs. If the BEC is a switcher (like a voltage booster for 1s LiPo cells) then it helps filter out voltage ripple. But further testing might reveal that it is extraneous.
J2 is a jumper block to select the transponder ID number. Currently the code supports two ID selections.
As you can see, there's not much to it! A 74AC86 exclusive-OR gate serves as the oscillator, changes the carrier phase under control of the microprocessor, and provides high output current to the tank circuit. (I may change to the 74HC86 to reduce high-frequency emissions, but that will require increasing R4 and R5 to reduce the output current, giving less field strength. Right now the field strength is just about the same as my AMB and MRT transponders.)
One interesting thing that I mentioned previously about the design is that the tank is driven differentially (bridge drive), which substantially reduces the second harmonic level in the output spectrum. This could help with meeting emissions requirements.
The values of CT1 and CT2 might have to be changed to match whatever tank inductor you use. My original perfboard prototype used 16 turns of 30 gauge Kynar (wire-wrap) wire, while the PC board has 20 turns of traces (10 on each side). The ratio of the two capacitors will set the tank Q (CT1 larger gives higher Q), while the series combination of CT1 and CT2 sets the resonant frequency.
R1 was originally a limiting resistor for the shunt regulator inside the intended microprocessor, the PIC12HV609. It is shown as a diode because I have been using PIC12F508 microprocessors left over from another project. The diode drops the input voltage by about 0.6V to keep the 12F508 happy (it has a maximum operating voltage of 5.5V), and as a bonus protects the transponder from reverse polarity. Using the 12F508 (or almost any 12F series device other than the 12HV609) means the supply voltage to the transponder is restricted to 6.1V maximum. That's okay for virtually all BEC circuits, but is not compatible with a 5-cell NiMH or 2-cell LiFe battery. I stopped using receiver batteries a long time ago! Adding a separate Zener diode would let the transponder operate from the same large voltage range as the PIC12HV609 permits.
I am considering changing to the PIC12F683 for its larger memory and EEPROM.
The 47uF cap is probably not necessary for use with ESCs having linear BECs. If the BEC is a switcher (like a voltage booster for 1s LiPo cells) then it helps filter out voltage ripple. But further testing might reveal that it is extraneous.
J2 is a jumper block to select the transponder ID number. Currently the code supports two ID selections.
Howard, how you calculate the length of the L1 ?
on PCB : 20T of 1.1"
on prototype : 16 T of ?
The length of L1 is around 20x4x1.1" = 88" ? (use with 47pF & 62pF)
thank
11-12-2015 | 01:27 PM
#290
Tech Rookie
Joined: Sep 2014
Posts: 12
From: Wyoming, USA
Condac,
I have been getting 2 different results when using the java program rctcode , and the BSE.exe program. Using a transponder number of 3456789 I get, 00 F9 16 E1 CB FD 29 28 13 1D 3F
------------------------------------------------------------------------------------------------------------------------------------------when running the java program I get E1 CB FD 29 28 13 1D 13 3F.
I understand the F9 and 16 are the header bits, but the first bit 00, not sure what it is for. and then remaining 8 bits returned by bse.exe are not enough to fill the d1-d9. So I assume the java program is the correct one to use.?
I have been getting 2 different results when using the java program rctcode , and the BSE.exe program. Using a transponder number of 3456789 I get, 00 F9 16 E1 CB FD 29 28 13 1D 3F
------------------------------------------------------------------------------------------------------------------------------------------when running the java program I get E1 CB FD 29 28 13 1D 13 3F.
I understand the F9 and 16 are the header bits, but the first bit 00, not sure what it is for. and then remaining 8 bits returned by bse.exe are not enough to fill the d1-d9. So I assume the java program is the correct one to use.?
11-12-2015 | 02:50 PM
#291
The prototype coil was 16 turns and about 1.2" square.
01-18-2016 | 05:03 AM
#292
Tech Regular
Joined: Mar 2013
Posts: 261
From: London UK
Hi Howard
My decoder build is progressing well and I have knocked up a couple of PT's as well and have a couple of questions before I take the PT to my local track on Thursday.
Is the LED supposed to come on with power or during operation?
Does the J1 pin 1 going to GP4 do anything or was it potentially a remote control feature?
Thanks
My decoder build is progressing well and I have knocked up a couple of PT's as well and have a couple of questions before I take the PT to my local track on Thursday.
Is the LED supposed to come on with power or during operation?
Does the J1 pin 1 going to GP4 do anything or was it potentially a remote control feature?
Thanks
01-21-2016 | 05:03 PM
#293
Tech Regular
Joined: Mar 2013
Posts: 261
From: London UK
Hi Howard
My decoder build is progressing well and I have knocked up a couple of PT's as well and have a couple of questions before I take the PT to my local track on Thursday.
Is the LED supposed to come on with power or during operation?
Does the J1 pin 1 going to GP4 do anything or was it potentially a remote control feature?
Thanks
My decoder build is progressing well and I have knocked up a couple of PT's as well and have a couple of questions before I take the PT to my local track on Thursday.
Is the LED supposed to come on with power or during operation?
Does the J1 pin 1 going to GP4 do anything or was it potentially a remote control feature?
Thanks
I guess start with 5v supply then the signal from the crystal and track the PIC ip/op and gates.
01-22-2016 | 04:14 AM
#294
Hi Howard
My decoder build is progressing well and I have knocked up a couple of PT's as well and have a couple of questions before I take the PT to my local track on Thursday.
Is the LED supposed to come on with power or during operation?
Does the J1 pin 1 going to GP4 do anything or was it potentially a remote control feature?
Thanks
My decoder build is progressing well and I have knocked up a couple of PT's as well and have a couple of questions before I take the PT to my local track on Thursday.
Is the LED supposed to come on with power or during operation?
Does the J1 pin 1 going to GP4 do anything or was it potentially a remote control feature?
Thanks
J1 has no function at the moment.
Your troubleshooting plan sounds good. Check the supply first, then make sure the oscillator is running; its buffered output is at pin 11 of U1D, one of the XOR gates. Look for missing components or incorrect component values, and that the ICs and Zener are in the correct directions. If everything looks good there, you should see signals at pins 5 and 6 of the microprocessor, and at pins 6 and 8 of the XOR gates.
The LED should be on. If it isn't, then the microprocessor hasn't booted, or the LED is in backwards, or the resistor value is wrong.
Let us know what you find!
01-22-2016 | 08:20 AM
#295
Tech Regular
Joined: Mar 2013
Posts: 261
From: London UK
My apologies for this delayed response!
J1 has no function at the moment.
Your troubleshooting plan sounds good. Check the supply first, then make sure the oscillator is running; its buffered output is at pin 11 of U1D, one of the XOR gates. Look for missing components or incorrect component values, and that the ICs and Zener are in the correct directions. If everything looks good there, you should see signals at pins 5 and 6 of the microprocessor, and at pins 6 and 8 of the XOR gates.
The LED should be on. If it isn't, then the microprocessor hasn't booted, or the LED is in backwards, or the resistor value is wrong.
Let us know what you find!
J1 has no function at the moment.
Your troubleshooting plan sounds good. Check the supply first, then make sure the oscillator is running; its buffered output is at pin 11 of U1D, one of the XOR gates. Look for missing components or incorrect component values, and that the ICs and Zener are in the correct directions. If everything looks good there, you should see signals at pins 5 and 6 of the microprocessor, and at pins 6 and 8 of the XOR gates.
The LED should be on. If it isn't, then the microprocessor hasn't booted, or the LED is in backwards, or the resistor value is wrong.
Let us know what you find!
Racing tomorrow but hope to get some bench time Sunday!
01-22-2016 | 08:54 AM
#296
don't mean to hijack this thread but can someone tell where I can get one of those coax loop amplifier ? I just purchased a used one and looks like someone pulled on the coax cable and pulled it out of the little black box at the end of the coax and I assume that the loop amplifier ?
01-22-2016 | 09:16 AM
#297
don't mean to hijack this thread but can someone tell where I can get one of those coax loop amplifier ? I just purchased a used one and looks like someone pulled on the coax cable and pulled it out of the little black box at the end of the coax and I assume that the loop amplifier ?
http://www.rctech.net/forum/radio-el...g-decoder.html
Hopefully you will have good luck finding what you need!
01-22-2016 | 10:30 AM
#298
Tech Regular
Joined: Mar 2013
Posts: 261
From: London UK
My apologies for this delayed response!
J1 has no function at the moment.
Your troubleshooting plan sounds good. Check the supply first, then make sure the oscillator is running; its buffered output is at pin 11 of U1D, one of the XOR gates. Look for missing components or incorrect component values, and that the ICs and Zener are in the correct directions. If everything looks good there, you should see signals at pins 5 and 6 of the microprocessor, and at pins 6 and 8 of the XOR gates.
The LED should be on. If it isn't, then the microprocessor hasn't booted, or the LED is in backwards, or the resistor value is wrong.
Let us know what you find!
J1 has no function at the moment.
Your troubleshooting plan sounds good. Check the supply first, then make sure the oscillator is running; its buffered output is at pin 11 of U1D, one of the XOR gates. Look for missing components or incorrect component values, and that the ICs and Zener are in the correct directions. If everything looks good there, you should see signals at pins 5 and 6 of the microprocessor, and at pins 6 and 8 of the XOR gates.
The LED should be on. If it isn't, then the microprocessor hasn't booted, or the LED is in backwards, or the resistor value is wrong.
Let us know what you find!
OK, knowing the LED should light sent me first to the 5v and I had not soldered the zener the right way round (tiny little things) re fitted and we are great now. lovely strong signal on the test loop. I have fitted into my micro for tomorrows racing on an RC4 system so fingers crossed.
Thanks for the help Howard. Next the decoder itself.
01-22-2016 | 11:06 AM
#299
I got finished earlier today so could not wait to get to this.
OK, knowing the LED should light sent me first to the 5v and I had not soldered the zener the right way round (tiny little things) re fitted and we are great now. lovely strong signal on the test loop. I have fitted into my micro for tomorrows racing on an RC4 system so fingers crossed.
Thanks for the help Howard. Next the decoder itself.
OK, knowing the LED should light sent me first to the 5v and I had not soldered the zener the right way round (tiny little things) re fitted and we are great now. lovely strong signal on the test loop. I have fitted into my micro for tomorrows racing on an RC4 system so fingers crossed.
Thanks for the help Howard. Next the decoder itself.
http://www.rctech.net/forum/12228988-post134.html
01-22-2016 | 01:30 PM
#300
Tech Regular
Joined: Mar 2013
Posts: 261
From: London UK
Don't expect anything if you are using an RC4. The transponders are not compatible with it. They have been tested on the RC3:
http://www.rctech.net/forum/12228988-post134.html
http://www.rctech.net/forum/12228988-post134.html