volcon

I made the first revision of this device years ago, but it was when I transitioned to working-from-home full-time that I decided to give it an overhaul.  Hence revision 2.

It's a great, whimsical device that gives me a little bit of happiness whenever I need to adjust the volume level of music or a video call.

Here I incorporated some learnings from the intervening years.  Upgrades from the first revision included:

• Schematic and PCB layout completely redone but using KiCad instead of Eagle.
• Microcontroller changed from an AT90usb162 AVR to an ATmega32U4.
• Remove the serial Tx/Rx connector.
• Remove the reset tact-switch.
• Use smd components instead of through-hole.
• Connect with a USB type C connector instead of a USB type B.
• Have the PCB fabricated (JLCPCB) instead of the home-made copper-etch method.
• A couple of LEDs on the bottom of the PCB purely to visualise the gray code (Rev 1 had LEDs but they only barely shone through etched sections of the PCB).
• Generally improved and cleaner code (still using the LUFA library).

In action.  The LEDs are a fun way of visualising the gray code.

Here it is next to another project (macr0).

This was a few years ago but I did record my goals for the initial revision of volcon:

• The optical encoder parts (sensors and disk) were salvaged from an old track-ball.
• The "knob" was made from the head drum of a VHS VCR (remember those?). This is the part that spins and is used to adjust volume on my PC.
• The optical disk was fixed to the shaft and optical sensors mounted off some strip-board and attached to the base of the drum.
• This assembly is mounted to a custom PCB with some nylon stand-offs. The PCB became the base of the whole unit.
• I cut some wooden rings to enclose the electronics and the base of the VCR drum.
• The custom PCB was designed in eagle and etched at home from some single-sided copper-clad board. The circuit was designed around an AVR at90usb162.
• The code is written in C and implements the LUFA library developed by Dean Camera.
• The whole unit plugs into a PC via USB and is automatically identified as a HID - no drivers required (tested in Debian Linux and Windows).
• It's a very simple device - rotate clockwise to increase volume, counter-clockwise to decrease.

Rev 1 PCB was a home-made etched job.  Some minor bodging required:

PCB top-side:

The first revision was pretty ugly: