Here's a small hardware challenge for you. Plug your phone into a charger. How much current is it drawing? The conventional method of figuring this out will, in the best case, require opening up the charger and futzing around with multimeter probes until you can get a measurement. The worst case scenario involves stripping a USB cable. The dollar store has plenty of USB cables, yes, but you get funny looks when you buy their entire stock. This is the solution to that problem. It's a small board with a USB Micro B connector at one end, a 'normal' USB A receptacle at the other end, and test points in between. It does one thing, and it does it well. If you're down with experimenting with USB, the ID pin on the Micro B connector is also broken out. If you're developing something with USB OTG, this will make things easier.In addition to a board with a USB A receptacle, a USB Micro B connector, and a few test points, you also get a very cool OLED backpack. The display on this backpack reads out the current, voltage, and wattage. It can also log the data to a computer with an accompanying app to graph the information being collected. Assembly is a snap; just solder on the headers, and solder on the OLED module.The logging and graphing capabilities of the backpack are incredible. With the app developed just for the USB Tester 2.0 backpack, you get live feedback of the current, voltage, wattage, and the voltage on the USB data lines. All the data can be saved to a file, allowing you to do fancy power analysis of USB peripherals. There are a ton of uses for the USB tester, and one thing we'll be doing in the future is figuring out how much power it takes to compile the Linux kernel on a Raspberry Pi. Yes, that will take many, many hours, but what an interesting example of what you can do when you're able to log current and voltage straight to a computer. The USB Tester 2.0 was designed by FriedCircuits.
USB tester OLED backpack
.96" OLED Module (SPI, 5V Power Supply) 128x64 resolution
OLED module IO high input- 3.2v-5.5v