The good thing of my little Rigol DSO is the USB port, where I can pop the flash and dump data in CSV. However, when you have thrown in some bash/python script to analyze the data, or just want do download the pics, you have to remove the usb flash. In the first case, you get bored popping flash in and out pretty soon.
At least I am, sine I’m a still a lazy programmer.
So, what’s the deal?
I took a look at the junk around, and found a nice switch. The I etched a small PCB, and fixed the whole thing to the shelf. I will still have to cover the pcb with urethane, though. Pics follow:
Basically, it’s dumb. Really dumb. You connect the flash to the slot, you connect one cord to your rigol, the other one to some PC. It just switches the 2 data lines from one device to another. So, when I want to connect it to my tablet, instead of rigol… I just flip the switch. Later, after some testing I added 30k pulldown resistors on the data lines, to eliminate some false device detections, when the device is switched off, or not present. (Conductive flux?)
There’s also a known bug with some devices: since power doesn’t get switched, the usb device doen’t get a cold-reset. And they do not get resetted properly. In my case popping another card reader fixed the issue. Making the switch disable the power for a short time will also allow these broken devices to work.
Kicad project files are here. (Schematics are messy – I was in a hurry)
NB: remember to grab eagle converted libraries for kicad, since they have that nice miniusb jack module I used here.