u/KS-Elektronikdesign

I have designed and built a test jig that will automatically test a small USB output for bench power supplies adapter called USBpwrME. The USBpwrME allows users to connect USB powered electronics to a power supply during test, evaluation troubleshooting etc.

Test jig in action

The test jig is built around the PIC18F27K22. This is my goto chip at the moment. It has a lot of configurable peripherals, ADC with really high resolution and a huge amount of memory for being a small MCU. And wide supply voltage range!

Test sequence will cover all the functions of the USB adapter with as few operator interactions as possible. One "funny" mistake i made during the design was not noticing that the relays i use has actually polarized coil so the pos/neg has to be connected in correct way to make the relay click. I missed this so i needed to hand modify all three relays.

Second mistake i made was actually a bit harder to foresee. One test that is performed is to invert the the input polarity to the USBpwrME to see that the polarity protection works. Well the design mistake was that the GND between the jig and the adapter is connected together thru the GND shield of the USB cables. So when the polarity switches the test jig short-circuits itself and restarts.

I solved this by adding in the test sequence when to actually connect the USB cables and performing the polarity test just before.

Even my eight year old son can operate it :) :)

Quite happy although with the result

I have designed and built a test jig that will automatically test a small USB output for bench power supplies adapter called USBpwrME. The USBpwrME allows users to connect USB powered electronics to a power supply during test, evaluation troubleshooting etc.

Test jig in action

The test jig is built around the PIC18F27K22. This is my goto chip at the moment. It has a lot of configurable peripherals, ADC with really high resolution and a huge amount of memory for being a small MCU. And wide supply voltage range!

Test sequence will cover all the functions of the USB adapter with as few operator interactions as possible. One "funny" mistake i made during the design was not noticing that the relays i use has actually polarized coil so the pos/neg has to be connected in correct way to make the relay click. I missed this so i needed to hand modify all three relays.

Second mistake i made was actually a bit harder to foresee. One test that is performed is to invert the the input polarity to the USBpwrME to see that the polarity protection works. Well the design mistake was that the GND between the jig and the adapter is connected together thru the GND shield of the USB cables. So when the polarity switches the test jig short-circuits itself and restarts.

I solved this by adding in the test sequence when to actually connect the USB cables and performing the polarity test just before.

Even my eight year old son can operate it :) :)

Quite happy although with the result

A really good space for me and my projects.

Worth noticing is the home made ESD gun that can deliver 7-8kV discharge, and a really primitive compressed air tank made of an old fire extinguisher connected to a small airbrush compressor. Perfect since it's non oil tech. Use it mainly for my hot air soldering station. Below the blue compressor there is a homemade heat chamber for temperature tests. Really bad pic but it can be seen on the overview picture. Also my latest project that i'm working on, that i have named USBpwrMe connected to the bench power supply output. Enjoy :):)

Every time i want to power something that is USB connected with my bench power supply i cut some USB wire and made some dodgy solution. And when i was done i threw the cable away 😄. So next time i went through the same procedure again . Got really tired of this and built my own adapter. Well that is how i came up with this project. A simple adaptor with one USB-C and one USB-A connector to make it backward compatible.

Works perfect when i just want to power raspberry pi and have full control of it's power consumption. It has some safety features such as over voltage protection and wrong polarity protection.

Every time i want to power something that is USB connected with my bench power supply i cut some USB wire and made some dodgy solution. And when i was done i threw the cable away 😄. So next time i went through the same procedure again . Got really tired of this and built my own adapter. Well that is how i came up with this project. A simple adaptor with one USB-C and one USB-A connector to make it backward compatible.

Works perfect when i just want to power raspberry pi and have full control of it's power consumption. It has some safety features such as over voltage protection and wrong polarity protection.