upy-switch-led-panel

MicroPython switch and LED panel

Description

Uses a Micropython Pyboard to provide a one-touch interface to start and monitor selected jobs on a GNU/Linux PC.

It works by binding systemd jobs to input pins (for triggering) and output pins (for indicating via an LED whether that job is running).

It talks via a serial protocol over the USB interface.

Inputs

Currently I'm using tactile switches, each debounced by a low-pass RC filter. I find a 2.2 kOhm resistor and a 1uF capacitor works quite well, on the Y pins starting at Y1. Powering these tactile switches using the 3V3 and GND pins on the Pyboard.

               --T--       _2k2_ 
    3V3 <------o   o------[_____]----*-----------> Yn
                                     |
                                  -------  1uF
                                  -------
                                     |
    GND <-----------------------------

Outputs

LEDs, each with a 100 Ohm resistor, on the X pins starting at X1. The X* pins are connected at the LED anodes, and the LED cathodes are connected via a 100 Ohm resistor to the Pyboard GND pin.

X9 is currently used as an indicator for 'not seen host yet'. When the pyBoard starts up the X9 pin is brought high, and when the host writes line 'HELLO' over the serial line it is brought low.

Of course it's all controlled in software on the Pyboard, so can be changed at will.

                    ^^            _100_
    Xn <-----------(>|)----------[_____]-------> GND

Host side

The host runs a small Perl 5 script that communicates over /dev/ttyACM0 with the PyBoard, monitoring and starting the systemd jobs specified in /usr/local/etc/upy-switch-systemd/jobtab

There's an example jobtab in the 'examples' directory of this repository.

In host/ you'll find an example .service file that should start the script when /dev/ttyACM0 appears on your system, and stops it when the device is removed.

Copyright and License

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

nmbooker / upy-switch-led-panel