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Dexcom transmission #45

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danpowell88 opened this issue Mar 27, 2016 · 2 comments

danpowell88 commented Mar 27, 2016

How is the dexcom transmitter sending its values over the air, ant/bluetooth etc? Is there any guidance on frequencies etc

ijustlovemath commented Mar 29, 2016

It's written as a serial packet over the Wixel's UART bus:
https://github.com/StephenBlackWasAlreadyTaken/wixel-xDrip/blob/master/apps/dexdrip/dexdrip.c#L253-L263

You can hook up the Wixel to a computer via USB and listen for the incoming packets using any basic serial terminal. The frequencies/radio scanning are all handled by the Wixel's microcontroller in this function: https://github.com/StephenBlackWasAlreadyTaken/wixel-xDrip/blob/master/apps/dexdrip/dexdrip.c#L421

Specifically, the call to the Wixel's API is made here: https://github.com/StephenBlackWasAlreadyTaken/wixel-xDrip/blob/master/apps/dexdrip/dexdrip.c#L440

After this, the packet is formatted into the struct defined near the top and printed over UART.

If you're wondering how it scans for the packet, that's done in the get_packet() function: https://github.com/StephenBlackWasAlreadyTaken/wixel-xDrip/blob/master/apps/dexdrip/dexdrip.c#L476-L496

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danpowell88 commented Mar 29, 2016

Cheers!

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