Enhancing a Magnifying Headband with Auto Sensing Light -- Episode 585

Nice build Katie.

You are probably going to have to search through you circuit and get some accurate current readings to trace down the culprit.

I just recently discovered that this kind of thing exists:

Ultra-thin gooseneck, with M4 thread : ) 

(Image source: Aliexpress)

I feel this could be key for some sort of lighting solution.

The hole through it is big enough for a a few very thin wires to pass through (I tested with a couple of lengths of 30AWG insulated wire, but perhaps 3 wires could fit, not much more!).

I originally got it for a PCB microscope, but as usual, feature creep has occurred and I'm still working on it.

This is another interesting and useful looking project.

Attention to the quality of lighting these days is often hard to find and it appears that brightness has more often than not taken priority over the quality or control of lighting.

A comfortable head-worn light with a good level of light control, producing even light without hot-spotting, would be a valuable visual aid for all sorts of activities.

A bit late to the party perhaps but I noticed that the SAMD21 power manager has a 'reset cause' register (RCAUSE) which can tell you the reason why the device reset.

 https://ww1.microchip.com/downloads/en/DeviceDoc/SAM_D21_DA1_Family_DataSheet_DS40001882F.pdf#page=158

Mapping these to some GPIO pins might help with diagnosing future issues.

I see.. I hadn't noticed the black blob comment (I watch all YouTube videos at high speed) but can imagine there's something there that may be interfering. 

So this is wired after the headset on/off switch?  How about wiring it before the headset on/off switch and just add a new switch.

Just a minor note.

measure.RangeMilliMeter returns an unsigned 16-bit integer and you're storing the value in a signed variable and then doing a "less than" comparison. Probably not an issue overall, but it is kind of messy.

I'd tested the software and it isn't that, but seemed the likely cause to begin with. Powering from USB it works perfectly, removing the switch with the "blob" which appears to be a switch IC with power off timeout also fixes it. So it seems the cause is that blob type circuit, which is a pain, as the moulded switch would have been nice to keep, and the auto timeoff is a nice feature

Yes, the schematic includes that for the red LED that I was using whilst testing on breadboard. The LED on the magnifier had a 10ohm resistor on the PCB with the switch component on it going to the LED moulded in the plastic housing.

Interestingly it isn't causing a brownout, the micro continues to be. up, and in comms with the sensor the whole time.
Removing the switch and replacing it with a latching switch fixes the flickering (There may be a slight hint, but I may also be seeing things by this point!)

Thanks, it was a neat little project, and I like it when a project can be useful.

That would be a good call based on the time interval, and the range check, but I did try that and it made no difference