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RCHourglass DIY Lap Timing (AKA Cano revised)

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RCHourglass DIY Lap Timing (AKA Cano revised)

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Old 12-20-2018, 05:28 AM
  #361  
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It seems that emc was not the high priority for the esc guys. I can measure high ringing at the esc terminals at every change of pwm (falling and rising). At full throttle pwm is 100%, so ringing is only at motor commutations. I tested without mounted Amb transponder and the noise is still the same at loop amplifier. Unfortunatelly all of the tested esc shows the noise, overall I checked 7 different escs.
The frequency of the noise is below 1Mhz, do you think it would be possible to add some filter?
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Old 01-27-2019, 03:03 AM
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Default Amb20 Decoder diy transpinders

Hi guys
Does anyone inow what diy PT will work with the Amb20 decoder ?
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Old 01-28-2019, 05:25 AM
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I don't have access to Amb20 transponders, sorry. If the signal is still 5MHz BPSK with the same preamble, monitor mode could be uset to capture the transponder packets a see if the firmware can be modified to mimic them.
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Old 01-29-2019, 10:27 AM
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Sorry for the late response, to many work....

On the Amb20, the frequency is about 3.68 MHz and i don't have the time to work on.
I have the idea to try to mix the frequency to have 5MHz and try to read with the decoder

Thor
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Old 01-30-2019, 01:00 AM
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Thank you for the response guys. Much appreciated.
We basictly sitting with an AMB20 system at our track but the hand out transponders is starting to pack up.

Any suggestions on what PT will work on the AMB20 or what modification i can make on the decoder to be able to register PT ?
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Old 01-30-2019, 03:48 AM
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The RCHourglass transponder can be easily converted to send a 3.68MHz signal (or 3.58MHz...these are 'standard' values). The crystal must be changed from 5MHz. The antenna must be retuned for the new frequency (different number of turns and/or capacitors).
The problem is finding the packet data that must be sent, and changing the transponder firmware data. Also (small change) fine tune the delay time between packets since it's related to the system clock.
How to find the packet(s) sent? Use an oscilloscope and/or run a modified version or the RCHourglass decoder that runs the front end at 3.68MHz. The decoder probably needs a 'relaxed' preamble detector and 'Monitor mode' must be used. It's also possible that the transmitted telegram is shorter than RC3 transponders, so the trailing part of the packet seen in monitor mode is probably garbage.
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Old 01-30-2019, 04:59 AM
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To my knowledge the AMB20 does not work with packages but with tone coders/encoders.

I know someone who made a simulair systen based on the idea of the AMB20. He made transponders with an 5MHz AM transmitter and a tone coder. On the other side he made an AM receiver with tone encoders which were read on the parallel port of the PC.

Every transponder had theit own tone frequency.
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Old 01-30-2019, 09:27 AM
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Originally Posted by Roelof View Post
Every transponder had theit own tone frequency.
If that's the case, I'm afraid there's no way to easily modify RCHourglass transponders to simulate AMB20 transponers...

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Old 02-03-2019, 02:31 PM
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Hi guys,

great thread going on here. I’m a member of my local roc boat club, where we race various classes of boats, we currently do manual lap counting but are looking to bring in some sort of electronic counting. I’ve been following this thread for a while now, but need a few questions answering.

Does anyone one know if this setup will work on water with the loop antenna suspended 30-40cm above the water?

second question is are there any component lists for the transponders/decoder & amp?

thanks

blazin
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Old 02-04-2019, 10:27 AM
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At least another user is using a desgin derived from Cano decoder (from which RCHouglass comes from) for rc boat timing. What he told me is that he's using a passive loop (100% Mylaps compatible) had to redo the loop amplifier and 'clean' the power supply to lower the noise and be able to use a longer loop needed for boat racing (2x18m). Sorry but I don't have any more details about it.
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Old 02-11-2019, 02:45 PM
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Hi! I'm ready to start the decoder build but i found loop amplifier schematics difficult to understand. Those jumpers blow my mind. What are they for? I only know the basics on electronics. Thank you in advance
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Old 02-12-2019, 07:28 AM
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The jumpers are used to tune the circuit to the loop wire length. From Howard Cano specs:

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.

I use no jumper, and avoided J4 components R12 and C6.
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Old 02-12-2019, 02:20 PM
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Originally Posted by mv4wd View Post
The jumpers are used to tune the circuit to the loop wire length. From Howard Cano specs:

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.

I use no jumper, and avoided J4 components R12 and C6.
Thank you! When you refer to wire length what do you mean by 9'x1' ?
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Old 02-13-2019, 01:48 AM
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It's the size (in foot) of the area of the detection loop. For example I use 9'x1' loop (about 2,7m x 30 cm). That means you need around 6 meter of cable.
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Old 02-13-2019, 03:28 AM
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Originally Posted by mv4wd View Post
It's the size (in foot) of the area of the detection loop. For example I use 9'x1' loop (about 2,7m x 30 cm). That means you need around 6 meter of cable.
awesome, thanks!
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