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mv4wd / RCHourglass

DIY lap timing system
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Redesigned power supply #2

Closed fz1nfx closed 5 years ago

fz1nfx commented 5 years ago
  1. Redesigned power supply. Very small linear regulator with included reverse polarity. Only one external capacitor needed.
  2. Added button
  3. Added prog connector
mv4wd commented 5 years ago

This is a nice change to make the circuit smaller. Few things to notice: max operating voltage is 20V, vs 30V of lp2950cz. If running form bec, it should be no problem. I'm afraid programming with full circuit mounted (through J2 connector) will overload the PSOC outputs beyond specs. The antenna is in parallel with the programming serial lines. It should be disconnected for programming.

fz1nfx commented 5 years ago

Programming through J2 connector is working OK (with full circuit mounted) Tests were done with:

  1. MPLAB ICD3 programmer - works OK
  2. Decoder RCHourglas (PSOC) - works OK
fz1nfx commented 5 years ago

There is one more change/option - 20MHz crystal. Of course, software needs to be changed.
With small crystal it is possible to reduce size of transponder to 15x15mm Today I build transponder with integrated antenna and small crystal. Works fine.

screenshot 107

mv4wd commented 5 years ago

Added contrib subfolder under transponder schematic