This simple circuit is presented and assembled well. The attention to detail is top notch. battery clip and pcb quality are outstanding. Amazing writeup at https://samueldperry.com/2017/12/25/multi-led-joule-thief-v2/.
These are really cute and a great way to have little lights in lots of places without resorting to tea lights. Super fast shipping too! I ordered them Friday night, he shipped on Saturday and I had them on Monday (in Seattle).
Such a great idea for a circuit and the size being the same as a single battery is perfect. Love that it works using only 3 external components. The 17 LEDs are very bright which is surprising given that the battery powering it would typically be thrown away. The 3D-printed power switch is also very clever and a wonderful addition. I bought two and placed them on the nightstands on each side of the bed and could easily buy a bunch more and leave them around the house for when I need them. Excellent product!