Project update 9 of 10
I’m happy to report that all orders have been fulfilled. More importantly, there were no quality issues and the batch yield was 99%, with every single unit fully tested and logged. The only issue we had was the factory forgot to include the screw terminal block on some units, but the part was included later on with the orders, which contributed to the shipping delay.
I will continue to provide product support, so if you have any questions please feel free to contact me using the Crowd Supply project page or open a GitHub issue. I will also be working on a new project that has been brewing in my mind for a while, but that’s for 2022 or when the chip famine ends! In the meantime, I’ll be scrapping devboards to build prototypes as I presume everyone is doing?
Ollie vs USB Killer
A question that I have been asked multiple times is, "Why do I need isolation?"
The simple answer is, "to protect your computer by isolating the USB port". No matter if you’re a hobbyist or an engineer, at some point you’ll be working with voltages higher than 5V. There are many examples of people accidentally damaging their computers while testing prototypes. Last year before I designed Ollie, I was testing one of my projects and I accidentally connected my un-isolated USB to UART pins to 130V DC, instantly frying it. Luckily it was not connected to my 5000$ company laptop!
To test the isolation, I decided to do a simple experiment. Although the outcome was predictable, it was interesting to see the result. I connected a USB killer to Ollie USB downstream port. If you’re not familiar with USB Killer, it’s a USB device that generates -230V on the USB data pin.
As you see in the video, the TVS diodes absorbed most of the energy, and the USB hub also did not survive, failing to short and causing the power supply to shut down. After replacing the USB hub it came back to life!
I designed a 3D enclosure last year, and you can find the step files on GitHub. The bottom screws from the PCB enclosure can be used to hold it together. I will also upload the drawing, in case someone would like to make their own.