USB_Attenuator_Switch_Stacklight
USB control of HP step attenuators, Coax Switches, and Stacklights. Related project: my USB Dual SPDT project
This project is an STM32F411 based USB controller, originally for scavanged HP microwave step attenuators, but I've also used it to control microwave coax switches and a stacklight at my desk.
The hardware design files are in doc/
This device uses FreeRTOS, and implements two interfaces on the bus...
- A CDC-ACM interface with a simple commandline monitor
- A simple COMMAND-RESPONSE packet interface on bulk endpoints 0x1/0x81. It's this interface that the perl code in perl/ and perl/test talks to. It's made to be machine-machine.
The board has a USB 5V->12 or 24V step-up converter. The old HP attenuators I have use 24V, my switches and stacklight use 12V. Change a resistor in the DC-DC converter according to your intended use.
It's just a USB->GPIO device with some high voltage switching ability. FET switches can be loaded for high-side or low-side switching, because you never know what you're going to scavange. See the schematic.
The controller consults EEprom for USB identifying material, so one board and software load can fit many uses.
After cloning, run the bootstrap script to get the required submodules.
So, here's an example of a stacklight:
And, running a couple of Dow-Key SP8T's and Dow-Key SPDT's through a breakout board:
