Exiting news and a cool experiment.

A project log for USB Power Injector

USB Power Injector allows for a way to power up USB 2.0 devices from a lab power supply, while allowing data transfer from host to device.

Nikola ManolovNikola Manolov 10/06/2022 at 08:570 Comments

First of all the exciting news.

I'm extremely happy to announce that I have started a CrowdSupply campaign in order to get the USB Power Injector to people who would find it useful. If you are interested feel free to check it out at CrowdSupply. Now to the experiment

Fast dynamic current measurements

Photo of the setup.

For some measurements using just an amp meter to capture current draw may be insufficient. Let’s say we are trying to capture the maximum current drawn by a Wi-Fi module while it’s making a HTTP request.  Let us explore this exact task using a module with ESP8266 Wi-Fi enabled microcontroller, Micsig CP2100B current probe and a scope. 

The module is programmed to make an HTTP request every second.

Capture 1 at 100uS / division
Capture 1 at 100uS / division
Capture 2 at 100uS / division
Capture 2 at 100uS / division
Capture 3 at 500mS/division.
Capture 3 at 500mS / division.

As we can clearly see, capturing the maximum current draw is trivial. As well as capturing how often and for how long the transmitter is turned on. This could be of great help when developing battery powered devices, where minimizing the power draw is paramount. Since the USB Power Injector uses standard 4mm banana plugs, it would be equally easy to use a different kind of current probe. For example it would easily interface with popular uCurrent Gold developed by Dave Jones.