If you are citizen of an European Union member nation, you may not use this service unless you are at least 16 years old.
You already know Dokkio is an AI-powered assistant to organize & manage your digital files & messages. Very soon, Dokkio will support Outlook as well as One Drive. Check it out today!

IntegTheremin

Page history last edited by MrTundraMan 10 years, 11 months ago

Integrated Theremin

The Integrated Theremin combines five of the Theremin boards into one design. The boards included are:

The board has additional features including:

Added connection to allow Microprocessor to monitor (via A/D) the VCO level for smoother volume control transitions

Average voltage into divider is 6V
Divider resistors 2.2K, 4.7K
Divider ratio is (2.2/(2.2+4.7)) = 0.31884
6V * divider ratio = 1.913 V
1.913V * (1023 counts/5V) = 391 counts
Peak voltage is 12V - scales to 3.82V which is safely below the 5V input of the A/D

Measured the average voltage and it wasn't 6V as expected, it was 5.3V which correlates well to the 346 count
Where is the transition supposed to happen with respect to the waveform to write data to the pots?
A/D sample rate is around 10K samples/sec
If the max freq is 1KHz that means that the waveform is only sampled 10 times per cycle so there could be a large step in volume
Start up question as well - the board needs to be autocalibrated at startup
May need hardware assist to cycle FSYNC at zero crossing
May want to connect the data and clock to the MOSI and SCK lines instead of PIO lines to speed up transfers
May want to use logic analyzer to debug

Board layout is slightly under 50 mm x 100 mm to use SeeedStudio service ($30 for 10 pcs).
Board has four mounting holes
New schematic design using hierarchical sheets
Split Power and ground planes (+12V/+5V) at center of card with jumper to connect GNDs