First major change to this system in several years; I swapped out the ‘old’ lcd display with this ‘new’ LED backpack module. It uses 4 alpha-capable led characters and I chose to buy the classic red color (works very well behind red plexiglass bezels).
Most of the circuits are all on production green-boards but the front panel is new and so its a perf-board work-in-progress. There are 3 buttons on the left and those control the volume in fast large-jump movements. The rotary encoder on the right moves in smaller 1dB increments. The display shows native dB from -99 up thru 0 (0 is no attenuation or maximum ‘volume’).
What is also very new, here, is that I removed IR (direct) control and went with xbee/zigbee modules for rf packet radios. These are two-way (IR is one-way) and lots of things can easily interface with xbee (being simple ascii 9600 baud over TTL signaling). With xbee in place, I can have a computer control this preamp and even display ‘text’ on the front panel LEDs.
More background on the alpha 10 preamp: www.amb.org/audio/alpha10/ (I’m the designer of the LCDuino, the delta1 and delta2 audio control elements).
photo from alternate angle: www.flickr.com/photos/linux-works/18456995428/in/photostream
view with full chassis dress: www.flickr.com/photos/linux-works/18622950416/in/photostream
Tagged: , adafruit , adafruits , LED , backpack , i2c , spi , serial , remote control , arduino , nano v3 , electronics , DIY , pc board , perf board , soldering , laser cutting , chassis , delta 1 , relay attenuator , audio preamp , audio , preamp , xbee , zigbee , embedded , IoT , C coding , realtime