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A project log for SubPos Ranger

The SubPos Ranger allows you to accurately measure distance or obtain your position indoors for all hobbyist robotics applications.

BleckyBlecky 06/28/2016 at 16:570 Comments

I had meant to get a demo video up the other day but was battling with random issues with the system.

The issue was that the node batteries were running low as I hadn't charged them in a while. The MCU was still running, but the TRX chipset was failing to transmit. I have implemented a battery low warning monitor by using the internal bandgap reference on the xmega to solve this (I will implement functionality that sends this info to the client too, but for the moment it's just a blinky LED).

I have also been running into intermittent lockups on the Ranger. It turns out there is some errata in the TRX that leads to a "potential long PLL settling times". While this was handled, what wasn't handled was an unknown errata issue where the PLL never settles or initialises. This looks to be settled now as I perform a TRX reset when this occurs (after a longer timeout period; a few ms).


So, the video will have to wait a day or so.

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