Remote controlled volume knob
Knopf, der German: button, knob (Pronounciation: /knɔpf/)
A project to upgrade an amplifier volume knob from a simple regular potentiometer to a digital one that still can be controlled directly at the amplifier but also via an infrared remote control.
Replaces the regular potentiometer with a DS1882 and a rotational encoder. Visual feedback with a charlie-plexed LED ring.
The interesting part is the infrared remote control: another rotational encoder, with an infrared transmitter: a wireless extension of the volume knob.
The rotational encoders have a secondary push-button function which is used to enable muting. Another press on that button will un-mute and go back to the original volume.
Remote control sender
The sender is a 20mm round PCB and thus roughly the size of the volume knob and the diameter of a CR2032 battery.
Provides a rotational encoder with an integrated button (used for 'mute'), two Infrared LEDs to send. Microcontroller: Attiny44. Quiescent current: < 0.2 μA. Runs on CR2032.
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TODO: build acryilic housing.
Code in sender/ directory.
DigiPot Receiver
The receiver behaves like a logarithmic stereo potentiomter. It takes an input signal from a local rotational encoder or the infrared signal (amplified and prepared with a Vishay TSOP75338). It provides two 'potentiometer' outputs. The local encoder has a 32 step/turn resolution of which 30 are used (to have a visual 'gap' between min and max like in a regular pot).
Microcontroller: Attiny48. Runs on +5V (digital processing) and +/-6V (Analog). For these voltge rails, there is a little separate power supply PCB
Code in receiver/ directory.
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LED Ring
The LED ring is mounted on the front-panel of the amplifier around the volume knob. In this case, this is a 19mm knob, so the ring is 20mm.
It contains 30 charlie-plexed LEDs to display the current 'position' and the TSOP IR module. On mute, the current volume position is blinking (controlled by the DigiPot).
The round board connects with the main receiver board via a 12 connect, 0.5mm pitch flat flex cable.
| Render | Real |
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Mounted on Amplifier and final Remote Control
