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RCHourglass DIY Lap Timing (AKA Cano revised)

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RCHourglass DIY Lap Timing (AKA Cano revised)

Old 05-08-2024, 04:24 AM
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RCHourglass Manager does it for you. You can find in the source code. openAST in not 100% accurate. Having said that, if you want to 'forge' new numbers they will probably NOT work on Mylaps decoders, because it seems that even the number itself has some kind of CRC.
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Old 05-12-2024, 07:52 AM
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Originally Posted by gusdepaulasd
Guys, I finally managed to test the equipment on the track.
It worked perfectly, no missed laps, no fastama transponders detected.
I used the original decoder for the loop I used the MLA30+, 4.5m * 0.3m loop.
It worked fantastically, I'm very happy.
After a long time I managed to make everything work perfectly.

I have some questions that I think you can help me with.

1st, how could I put an LCD display on the decoder to show the transponder number that passed, number of hits, etc...
I saw that some people managed it but I didn't find how I could do it.

2 This question is simpler, lol.
The mla30+ has a beasing tee, I could incorporate this beasing tee together with the decoder so that it is outside my decoder box instead of the loop box itself.
I honestly don't think there will be any problems because everyone who uses the mla30 places this beasing tee glued to the decoder box, but it's better to ask than to have to do unnecessary work.

I thank everyone.

sorry i'm a bit late ....

i already made an LCD + Arduino :

RCHourglass DIY Lap Timing (AKA Cano revised)

you can take my code il the links ....

Have fun
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Old 05-29-2024, 01:28 AM
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Location: Lower Bavaria
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Last week we did tests with the Decoder and Transponder. Instead of the original Amplifier i use a modified MLA30+ (changed sma plug to BNC and power it directly without the BiasTee)
Registering mylaps Transponders worked fine.
I only have always low Hits at the Software, around 1 or 2, only when cars passing by slowly, hits increase to 10-20 or more. This happens with MyLaps and self built Transonders. And sometimes cars are not recognized when passing loop. And i got ghost-Numbers from the Transponders too. Unfortenaly i did not have my oscilloscope by me on the track.
Back at the workbench i did again tests with the oscilloscope. Here is a screenshot of TP8 and the feedback pin.
Next days i will go back to racetrack with the oscilloscope. Any ideas what can i test test/optimize? Thank you very much for help!
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Old 05-29-2024, 04:19 AM
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The waveform on TP8 seems quiteasymetrical, meaning that upper waveform is much higher than lower respect to zero. This can impair the zero crossing detection, but could also be caused by your probes.Please try to check voltage without signal (center waveform) and you might also want to investigate signal amplification. You might have too much input gain causing asymetrical clipping. If you can play with antenna gain. What I see is that waveform is quite 'slow' to get a good level after phase reversal. Compare the wave with the one you see in the wiki Decoder build instructions
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Old 06-01-2024, 01:22 AM
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Thank you for your help. Few days ago i was on racetrack with my eqipement.
Sadly we still got some problems.
I checked Voltage on TP8 without Transponder and the basline is looking very bad in my opinion. Very much peaks like you see in this picture:
Playing with the Gain-Poti at MLA30+ makes it a little better wenn turning it down but then i have more problems to recognize Transponders.

What i did too when i built Transponders, i changed C5 from 68 to 120p because it gave me a better amplitude at a single loop-wire at oscilloskope, but a longer "Ring-up time" at the waveform, and this happens after phase shift too? Could this be a problem too?

Here is a photo when a car with Transponder stands near the loop:

And my Decoder:

Thank you!
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Old 06-02-2024, 05:53 AM
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Two different things going on there. First, the bursts of noise might come from everywhere, and they seem quite powerful compared to the decoder signal. They might be real 'air' noise, they could be a noisy usb power, or they might be the pc or scope ungrounded power supply or ground loop. If you get that noise without the antenna connected (shorted) it's not from the air. Ttry to power just from battery. For the spikes in the transponder signal, those might come from a un-tuned loop. You will find in original 'Cano transpoder' thread the tuning relation with quick or slow phase reverse, and overshoots. It seems to me strange that you have overshooting in the normal sine part (without phase reverse). Can you just try and measure the transponder signal with just a loop of wire on the scope probe?
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Old 06-02-2024, 10:40 PM
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Default decoder , loop BOM

is anyone able to provide a BOM as a csv,xls file that i can then upload to digikey for ordering.

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