2023-10-20 (F) Weekly Summary

I used PVC pipes to experiment with round instruments. I carved a labium using a razor knife and a bit of patience. I made a laser-cut block for the pipes' mouth end, but I only got sound when I pushed the block to the window's edge. I designed a pinecone valve to experiment with different airflows, which worked best at 10-15%. I made several versions with different lengths and hole sizes, but none worked perfectly.
Cylindrical instruments

I did some experiments to determine the factors that generate tones. I cut up my 12" slide whistle and measured the frequency at different lengths. I repeated the process until the tube was 4" long. I also performed a similar test with a partially stoppered flute.
Experimental debris

I experimented with using a 3/4" thin-walled tubing instead of 1/2" schedule-40 pipe, which was less expensive and had more internal volume. I tested the wider tubes to determine if they would provide a lower frequency than a smaller diameter. After cutting the pipe into a 20" (500mm) piece and carving a labium, I found a length that produced a primary frequency and the next most audible resonance close to the DTMF tones to transmit a 2.
Working DTMF Phlute

I made a pipe for each tone, focusing on one frequency at a time. I used 1/2" PVC for higher-pitched column frequencies and 3/4" PVC for lower row frequencies. I had to swap my single wooden block to test the 3/4" PVC, and the final unit was much larger than I anticipated. I want to revise and make something portable.
Working but impractical

I shrunk the design to what I initially imagined. The technique was to cut a plain 3/4" pipe that matched the lowest frequency used by the rows and a 1/2" tube for the column tones. I added and widened holes until I found configurations that produced the desired pitches. I painted it red as an homage to the phreaking Red Box.
(0:06) Phlute REV 2

I made a second Phlute and wrote an Instructable using crucial details like hole diameter and position. I included screenshots from apps and glossed over failures. I plan to test a circuit with a DTMF decoder and sound amplifier so I can show off at conventions.
Instructable for Phlute

The rest of the summary posts have been arranged by date.
First time here?

Completed projects from year 1
Completed projects from year 2
Completed projects from year 3
Completed projects from year 4
Completed projects from year 5
Completed projects from year 6
Completed projects from year 7
Completed projects from year 8
Completed projects from year 9
Completed projects from year 10

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