So, we're a year on from Christmas 2017. What's going on with the Yapolamp?

I wanted to review the year we've had with the torch as we've now had the best part of two winters with it in use by my son. He has been thrilled with it and loved having it set "on" (bright) at bedtime, to then go into "always on" (dull) mode after about 12 minutes. The battery would last just under a week in this use profile and then get charged up overnight. I never got around to encasing the charging Tx coil in anything, so it has been sat as a bare circuit and coil on my nightstand and plugged into a USB phone charger when needed. The aluminium case always got tepid/luke warm during charging but I was never concerned about charging the torch. 

My son also really liked exploring dark corners of the house with his Yapolamp, especially navigating his way to our bedroom on dark winter mornings. We love the Yapolamp as much as our son as it's a good way to have more light in the children's room for e.g. administering Calpol at 3 a.m., without waking everyone up too much. Thanks to the "always on" mode, it's always easy to find in a darkened bedroom.

Sadly, in the last month the torch has stopped working properly, with all LEDs going dark. Charging puts it into "always on" mode briefly and sometimes pressing the button will turn it to "on" mode but more often than not, it turns completely off. I had always wanted to look at the efficiency of the LED driver circuitry (particularly the tiny inductor I used) and had wondered about the effectiveness of the wireless charging and battery life over time.

Since making V1 of Yapolamp, I have acquired an oscilloscope so can now actually check the reality against the theory of the LT spice simulations I did during the design (and then bodged around with NOPs to get a reasonable average current draw). 

So my intent for Yapolamp is (in no particular order, apart from 4):

1. Teardown V1 to see if I can spot a failure mode
2. Try and view the performance of the LED driver circuitry
3. See if I can discern whether a smaller-size inductor was a bad choice for the LED driver
4. Design and build a V2 Yapolamp, with today's older and less-inclined-to-lick-electronics son in mind...