VoltLink revD USB Serial Bridge & ESP32 Programmer | Voltlog #414

Ever since I’ve started offering the option for the Shelly programming cable, lots of people have ordered one because it makes the job of flashing an otherwise dangerously mains connected relay very safe by not having to power it from mains, but just supply it with DC power from the VoltLink itself.

But this video is not about that, it’s about the latest revision D of the board, the changes that it contains and some future plans.

So as you may have noticed there is no power LED on the VoltLink and to be honest for my personal use case I don’t really need one but I do understand people that want a power status LED so that they get a quick glimpse of whether the board has power or not.

Personally I think that because the VoltLink is so reliable in operation, the power LED is redundant but I do remember the times when I was using other cheap usb to serial adapters, there were the occasional issues with the micro usb connectors failing, with the on board chip failing, so it was nice to be able to see that you still got power to the board at least. Nonetheless, I added one to the new revision, placed it right next to the USB connector.

Now because I added these two extra components to my schematic, the LED and the resistor, I decided to switch to a resistor network to replace 4 x 1kilohm resistors with a single package to further optimize my BOM cost and DFM.

Another small change I did was to bump the 4.7uF decoupling capacitor on the USB to serial chip to 10uF because I was already using that value at the output of the voltage regulator. This once again, optimizes my BOM for using less parts as this will become important later.

And while I was revising the PCB, I also switched to these nice labels created with the Kibuzzard plugin for Kicad. No extra functionality because of these, but they do look nice.