Here’s a big “Thank You!” to all of you that have sent me private messages. To reiterate my previous posts, I won’t be offering assembled decoders in the foreseeable future (due to FCC regulations). I can provide programmed microprocessors for both the decoder and transponders, and unpopulated printed-circuit boards for the decoder, for those individuals and clubs wishing to build their own system. Proceeds from these items will help offset some of my development costs. Send me a personal message for prices.

At this moment I have a few bare decoder PC boards available. The loop amplifier PC boards will hopefully arrive shortly. Neither is necessary to build a working system, but they do make it much simpler!

As I mentioned in previous posts, I will forward the following files to anyone that desires them, for free: the decoder, loop amplifier, and transponder schematics, in TinyCAD freeware format; the PC board layouts for these, in FreePCB freeware format; and the Bill Of Materials (BOM) for these, in Excel 2003 format. Just send me a private message containing your email address.

This is a complicated project, so the constructor must have a thorough knowledge of electronics to succeed. While it would be great if every club had at least one such member, I don’t expect it. Unfortunately, I can’t help assemble boards. If your club does not have a suitable person to construct a decoder, you might try checking with local electronics companies for volunteers to help you. Electronics engineers and technicians usually love fiddling with projects outside of work. You might even convert them into RC racers!

Perhaps there are readers of this thread who could volunteer their time to help build a system? If so, let us know, and you can communicate directly with others who desire help.

I have some problem with the RC4 decoder.
The valid signal is present only 5 times for 50 tranponders messages.
When I use a old personal transponder I have always the valid signal with an transponder message.

I replaced the preamble detector data D7 to Vcc to skip the D7 value.
I have no more valid signal with this modification when I use the RC4 tranponder.

Have you the same problem with RC4 transponder ?
thanks

No problems with rc4 hybrid transponders.

Some loop amplifier for Howards decoder. Best work with 10m loop
https://pp.vk.me/c405718/v405718346/...29IsI5oCUA.jpg
https://pp.vk.me/c418920/v418920346/...Oiw-1QatuY.jpg

OK thanks you Payalneg, it's perfect your loop amplifier it's an alternative for the transistors schema......

For the old amb personnal transponder, Howard looks 24 bits after the valid signal; and he valid the transponder when the 24 bits is repeat 3 times, but how you detect an RC4 tranponder ?

I am recording 11bytes after preambule in 30 parcel of transmiting in RAM. If there are 3 indentical, this code recording in eeprom and in ram as verified.

For example my rc4 hybrid transponder:
5495805:

EC84418105A6B5BD70CF0000
E12AD9E1EED94E07830F4001
E12AD9E7EED94E07C30F4002
E12AD9E1EED94E07830F4002
38A8F9C1ECA67A7E4FCC4002
E12AD9E1EED94E07830F4002
E12AD9E1EED9CE07830F4000
E12BDBE1EED94E07830F4000
E12AD9E1EED94E07830F4000
E12AD9E1EED94E07830F4001
E27B5E0BC356B9B98CC24001
E12BD9E1EED94E07830F4001
F12AD9E1EED94E07830F4000
E12AD9E1EED94E07830F4002
E12AD9E1EED94E07830F4002
E242145FC145858D4CCF0023
E12AD9E1EED94E07830F4000
E12AD9E1EED94E07830F4004
D417A27CD8B9BA4E40CC4002
E12AD9E1EED94E07830F4002
E12AD9E1EED94E07830F4023
E12AD9E1EED94E07830F4000
E12AD9E1EED94E07830F4000
E12AD9E1EED94E07830F4000
E12AD9E1EED94E07830F4000
E12BD9E1EED94E07830F4001
E12AD9E1EED94E07830F4002
E12AD9E1EED94E07830F4002
E12AD9E1EED94E07830F4000
3B14155CCA79B54D73000002
E12AD9E1EED94E07830F4002
E243145FC145858D4CCF0000
E12AD9E1EED94E07830F4000
E12A58E1EED94E07830F4002
E12AD9E1EED94E07830FC000

This code "E12AD9E1EED94E07830F40" recording in memory and new number of transponder is 0xE12AD9 and 0x7FFFFF=0x612AD9 . In dec is 6367961

Hum...I do not understand the end of your sentence : and 0x7FFFFF=0x612AD9 ?

thanks for your reply.

its logical and

ok, this is an addition !

but another question, why you are doing an addition with 0x7FFFFF ?

ok, this is an addition !

but another question, why you are doing an addition with 0x7FFFFF ?

Becouse 0x7FFFFF 8388607 is 7digit number. So 0xFFFFFF 16777215 will be 8digit number. My system is based on ambrc protocol, where can not be 8digit transponder number.

CANO DECODER SUMMARY and SPECIFICATIONS
 

CANO DECODER SUMMARY and SPECIFICATIONS

With the number of questions I've received in private messages, it seems like a good idea to list in a single post all pertinent information regarding the decoder. I'll try to keep this updated as necessary.


LEGALESE: All information presented on this thread is free for use for personal, non-commercial purposes. The software is copyrighted, and cannot be reproduced. Contact me for licensing arrangements if you wish to produce and market the decoder.


AVAILABILITY: The Cano decoder is not available assembled. It must be constructed. I offer programmed microprocessors for this. Send me a private message for pricing. Proceeds from these parts will help offset my development costs.


TRANSPONDER COMPATIBILITY:

AMBrc personal transponder: tested okay.

MRT PTX: tested okay.

MRT PTX-20 (NS): tested okay.

Cano PT: tested okay. (Cano PT with cloned number will also function on AMB RC2 and RC3 decoders. Cano PT with "club" number will function only on Cano decoder.) Cano transponder specs are here: http://www.rctech.net/forum/12228988-post134.html

MyLaps Hybrid: tested okay.

MyLaps RC4: not compatible.

Note: Number indicated by decoder and software will not match the number indicated on the AMB or MRT transponder or in the instructions for the transponder. There is a small probability that there will be duplicate numbers for different transponders, though I have not yet encountered any for a sample size of about 30.


POWER REQUIREMENTS:

12VDC @ 100mA minimum if using decoder's internal 5V regulator. Decoder is polarity protected.
Or,
5VDC @ 100mA if running directly from USB port (bypassing decoder's internal 5V regulator)-- NOT polarity protected!


LOOP CONSTRUCTION:

Use 18 AWG stranded, insulated wire. Wire must terminate as closely as possible to loop amplifier input, with minimal lead-in length. Place loop 12" above track.

9'x1' to 12'x1' : No jumpers on loop amplifier.

6'x1' to 8'x1' : Use jumper at J3 on loop amplifier.

3'x1' to 4'x1' : Use jumper at J5 on loop amplifier.

Use 75 ohm coaxial cable with F connectors between the loop amplifier and the phase detector input amplifier.


PC INTERFACE:

Logic-level RS232, 115200 baud, 8 bits, 1 stop bit, no parity, no handshaking, no flow control.


SCORING SOFTWARE COMPATIBILITY:

ZRound Suite 1.12 Build 16 (tested on Windows Vista)
FlipSide Racing version 12.52 (tested on MacOSX 10.6.8. Compatibility issues with Windows Vista)


DOCUMENTATION:

The following files are available: the schematic in TinyCAD freeware format; the PC layout in FreePCB freeware format; and the Bill Of Materials (BOM) in Excel format. Send me a PM containing your email address if you would like me to forward these files to you.


ERRATA:

See post #222.


CURRENT REVISIONS:
Schematics: Loop Amplifier Rev B 6_11_13.dsn, Decoder_D 9_4_13.dsn
PC Boards: LOOPAMP 6_2_13.fpc, DECODER_B 5_29_13.fpc
BOMs: Loop Amplifier Rev B 6_11_13.xls, Decoder Rev C 9_4_13.xls
Software: Rev. B, sent in power-up copyright message.

Howard, Is it possible to replace U24 (74AC4040) on digital phase detector to 1/2 74HC393 ?
40Mhz frequency is the limitation ?

The 74HC393 specs are not quite sufficient for the operating frequency used. It might work, but is not guaranteed to do so.

ok, thanks.
Is it possible to know the AMBrc protocol ?

If you are referring to the AMB transponder messages, then I have no idea what they mean. Fortunately, it's not necessary to know this to clone transponders, or have the decoder use them.

That knowledge is necessary to create programs for new transponder ID numbers that would be recognized by AMB decoders.

I would not be surprised if MRT had this knowledge, but I don't believe they have ever "created" new ID numbers for their transponders.

Flip Side Racing has been kind enough to provide a test version of their timing and scoring software that supports the Cano decoder. We are now debugging the software, but I'll let everyone know when the final version is available.

Here's a big "THANK YOU!" to Flip Side Racing for these efforts!

The loop amplifier boards finally arrived. It only took six weeks! I sure won't be using that supplier again!

http://i1191.photobucket.com/albums/...psc16f96fd.jpg

Looking excellent on a PCB! I am going to build at the weekend if I get some time.

Did anybody try the LM319 version by Paypalneg? I made one up last night as it was a more simple circuit. Need to do some testing to see if I can make it work nicely.

You'll want to investigate re-biasing the inputs on the LM319. The circuit shown has the inputs operating out of the acceptable voltage range (1V to 3V on a 5V supply). Also, the gain is not well-controlled, since it is operating open-loop; this may cause erratic operation. And the spec sheets I checked listed a minimum supply voltage of 5V.

Howardcano,
Do I have to understand that the circuit with the LM319 not works properly with your decoder ?

Payalneg,
Have you modify something in the decoder to use the amplifier with the LM319 ?

The circuit might operate with the rest of my design, but there are no guarantees. I have not tested it. It's quite likely that Payalneg is using it with different circuitry. Hopefully he will let us know.

The loop amplifier I presented has all of the attributes that I required. If I thought it could have been simpler, I would have made it simpler-- but not at the expense of my design goals. One of those goals was (and always is, for me) maintaining operation within the published specifications of the components used. That's one way to increase the chances of success for the average builder.

No, its nothing to modifite in decoder schematics. Working pretty good with 5m loop.
http://cs416924.vk.me/v416924346/785f/2ZLUIEYFcNI.jpg

Hi!

Impressive work described in this thread!

Ive read through it and tried to figure out if the detection loop/amplifier would work with a AMB rc3/rc4 decoder.

Im looking for an alternative for the "connection-box-with-coax" cable that is present in mylaps store. My local club has more tracks than cables and mylaps price for the cable is a little bit high.

Would that be the amplifier + a loop?

Best regards
eslin

another alternative
 

Not sure how your COAX is run, but if you can move it around, you can run multiple loops off the same COAX. I put banana jacks on mine to plug into the loops... loops are cheap & easy to make... just a wire and resistor. Heres one I have the bananas in the wall.

http://www.rctech.net/forum/attachme...d-wgrii-1-.jpg

I also have had several loops made over the years. The RC2 Decoder manual gave instructions on how to make the loop. I even made mine out of 14 gauge copper house wire, just to see what kind of results I would get. It worked fine... :)

Here is the document from the manual. I made it big so you can read it. When it says the resistor needs to be opposite from the box, it really means, whatever your length of wire is, the resistor needs to be in the middle. So if its 20ft long, the resistor needs to be at the 10ft mark to separate the two pieces of wire. Then you solder them together.

This also works on the new RC4 box as well.

http://www.rctech.net/forum/attachme...1&d=1373126228

Thanks! but I know about the loops, we have used a selection of different cables for those, and also differing connectors.

Im looking for more "black boxes", for permanent installs on the tracks.
Thats why Im wondering if these "amplifiers", or this decoder systems loop/setup whatever components required in the end of the COAX would work with rc3/rc4 (which are really the same decoder, with just differing firmware).

(also I really do not want to hijack this thread and make it into one of those other threads with what kind of loop is used), just focus on "will this amplifier/loop work with rc3/rc4".)

Best regards
eslin

http://www.transponderservices.com/images/LIB.jpgTry this site for the box.

Transponder Services

I understand your concern with the AMB/Mylaps balun box, as they are quite pricey for what I understand is just a passive transformer! I also appreciate your concern about hijacking the thread, but I can't find any threads dedicated to the AMB/Mylaps decoder to suggest to you. When in doubt, you can always create a new thread. In any case, I hope you have received the information you needed.

The loop amplifier presented in this thread is not compatible with AMB/Mylaps decoders. It is certainly possible to design an active or passive replacement for the AMB/Mylaps balun, but I personally don't have sufficient knowledge of those systems to create one.

Ed and Jimmy, thanks for helping eslin!

I should remind casual readers that the loop Jimmy showed in post #265 is for AMB/Mylaps systems. The loop for the Cano decoder is a little simpler (it's just wire; no resistor is used), and details can be found here:

http://www.rctech.net/forum/12222187-post251.html

Thanks again Howard for all your excellent design in this thread. I have built the two amplifiers now, pictures attached. I get different voltages to your measurements at some points in the loop amplifier, need to investigate this further.

Two quick questions if I may, firstly what output is expected from the phase detector input amp during a phase reversal? At the moment I seem to get a "missing" pulse (in fact I seem to miss two cycles). Output from scope is attached, yellow is logic output and blue is sniffed with a scope probe.

Secondly did you add any filtering into the design? With no TX unit nearby I get spurious logic output at Khz frequencies. This does not occur when the loop is disconnected, so I am fairly certain it is other RF interference. I suspect this is because I have not yet tuned the loop to 5Mhz. I built revB but have not added the three extra jumpers at this time, only the single capacitor.

That's some very pretty prototype work!

Some variation in voltages is inevitable. If the parts values check out okay in the loop amp, then another step to take is either verify that the Vbe of the input pair (Q1 and Q2) match to within a few mV, using the diode check function on a multimeter. You can also use the optional input offset adjust pot to set the voltage at the junction of R8/R9. The voltage can vary a little, perhaps +/-0.1V. I'll update the schematic with an acceptable range when I get the chance. I've constructed several loop amplifiers now, always using transistors from the same production batch, and all have been functional with no adjustments.

Depending on the tuning of the transponder tank (and, to a lesser extent, the timing loop) you may see a missing pulse, or double pulses for a phase inversion. I believe that two missing pulses is also acceptable to the digital phase detector. In any case, please decrease the Q of the transponder tank so that it will return to its original amplitude quicker on a phase inversion.

Filtering is via the loop tuning (and for higher frequencies, the natural rolloff of the transistors). Spurious outputs are not unusual, as many noise sources contain energy in the frequency band we are using. During my experimenting, I located one particularly offensive source: the switching power supply on my laptop computer. Similar noise can result from the ESC and motor in the car. The preamble detector weeds out almost all of this, so the microprocessor can spend its time doing more important things.

Thanks.. I actually dislike through hole and especially stripboard, so I took some time over it. I'll hope to move it to SMD once it works.

I have not yet studied the decoder schematics in detail, I hope to start this week during vacation. How is it that the digital phase detector knows when the phase has reversed? You say that there "may" be a missing pulse, but in a perfect situation how does it recognise the modulation?

I am going to play with tank tuning values tonight to sort out the Q as you suggested, this should help.

Here is a quick description of the phase detector operation:

http://www.rctech.net/forum/12009638-post167.html

Hi Howardcano,

Can you explain how the RC4 decoder can filter out the PTX transponders? Afaik the PTX is a clone of the AMB PT so how can the decoder see if it is a PTX or AMB PT?

Great Thread. I was actually trying to analyze many years ago how the decoder system worked but never got a break through.

Thanks.

There are many possible ways to distinguish the old MRT from the old AMB, and I mentioned a few on my Transponder Design thread. But I don't know what method is used.

MRT has figured it out, though, and has released an updated transponder that is again indistinguishable from an old AMB transponder by the RC4 decoder.

So now it's up to MyLaps to 1) do nothing, 2) figure out other differences to look for and use as a basis to reject MRT transponders, or 3) simply don't count any MRT and AMB transponders anymore. Don't be surprised if it's #3.

Well attached is a picture of my high quality, made at the very last minute decoder! The green board is a Lattice CPLD and the stripboard contains an oscillator and Howard's phase detector input amplifier. The barely visible purple board (to the left) is a PIC breakout board. The whole thing is powered from USB.

The other picture is the loop amplifier which is slightly neater construction and is made to fit into a small enclosure.

I'm going to give it all a trial next week at a karting camp - will report back. Nothing like taking a development model to a real event :)

Thanks again Howard.

That loop amplifier is a work of art!

Good luck with the karts. It will be interesting to hear how well the system functions with the buried loop and all the ignition noise from the kart engines.

Day one of our camp and I've got mixed results. Works great under a carpet with some RC cars, but not with the loop which is buried in the go kart track.

The loop in tarmac for the kart track is rather long and too far apart (a few feet) - the cable is probably 2mm twisted copper. We are hoping to try a much thinner wire in the next few days.

Can you get the buried loop to resonate at 5 MHz? If it's too big, it won't tune high enough, and won't be effective.

Some news about my arduino / EPLD howardcano design decoder.
The EPLD and arduino interface are done, now it's time to develop the smart phone & PC software.
Hardware :
one arduino leonardo board
one ethernet shield
one PhaseDetectorInputAmplifier & ALTERA EPLD on prototype board
one Howard LoopAmplifier

http://img4.hostingpics.net/thumbs/m...63049Large.jpg

Thanks again Howard.

Very nice! It looks like you are making good progress!