Ultrasonic Theremin Problems

[Kraggy123]

Hi I recently bought myself a raspberry pi and decided to try and do the ultrasonic Theremin project. I followed it all correctly but no sound is being produced and I have no idea whether it is working or not.

The project I followed below:
https://projects.raspberrypi.org/en/pro ... c-theremin

[W. H. Heydt]

I think the root of your problem is in the word "ultrasonic". Why you expect to be able to hear it?

[W. H. Heydt]

I think the root of your problem is in the word "ultrasonic". Why do you expect to be able to hear it?

[rpdom]

I think the root of your problem is in the word "ultrasonic". Why you expect to be able to hear it?

Because it produces normal sound frequencies. The ultrasonic part is the sensors that detect hand movement instead of using antenna.

[Kraggy123]

Rpdom is correct, the sensor is simply ultrasonic the ultrasonic part, the speaker itself will produce normal sounds.

[rpdom]

Also I think I will build one of those someday. I already have the ultrasonic sensors

[Idahowalker]

Hi I recently bought myself a raspberry pi and decided to try and do the ultrasonic Theremin project. I followed it all correctly but no sound is being produced and I have no idea whether it is working or not.

The project I followed below:
https://projects.raspberrypi.org/en/pro ... c-theremin

When you did this part:

Code: Select all

while True:
      print(sensor.distance)
      sleep(1)

Did you get a print out of sensor distances?

[Kraggy123]

No I never got a print out of the distance

[Idahowalker]

No I never got a print out of the distance

Stands to reason why no sound.

What is the error message you are getting?

[Kraggy123]

At the moment I get no error message. It seems to run fine and there is no hint that it's gone wrong somewhere, except with no distances being printed and no sound being played.

[Idahowalker]

At the moment I get no error message. It seems to run fine and there is no hint that it's gone wrong somewhere, except with no distances being printed and no sound being played.

This code:

Code: Select all

while True:
      print(sensor.distance)
      sleep(1)

Change to:

Code: Select all

while True:
      print(sensor.distance)
      print ("did the thing")
      sleep(1)
      

Do you get a print out that reads "did the thing" whiles moving your hand in front of the ultrasonic once every 1.0+ seconds?

[Tzarls]

AFAIK there is a problem with the ultrasonic sensor interface in gpiozero - Basically the sensor won't detect any distance so any project based on distance will not work. I had to develop my own ultrasonic class using Pigpio to make the theremin and other projects work.

[Kraggy123]

I changed the code to the "did that thing" and It didn't print it or anything else.

[Idahowalker]

I changed the code to the "did that thing" and It didn't print it or anything else.

What are you doing to run the code?

[KLL]

also the SONIC part of that example seems to be old stuff.
but i try this:
in SONIC Pi (3.0.1)
test soundsystem with a
play 70 [Run]
now use this:

Code: Select all

live_loop :RPI_theremin do
  use_real_time
  a, b, c = sync "/osc/play_this"
  synth :piano, note: a, cutoff: b, sustain: c
end

[Run]

open a IDLE3 new file window

Code: Select all

# from https://projects.raspberrypi.org/en/projects/ultrasonic-theremin/
# but (looks like) gpiozero AND SONIC code not work!

# on SONIC use: and press RUN
"""
# Welcome to Sonic Pi v3.0.1
live_loop :RPI_theremin do
  use_real_time
  a, b, c = sync "/osc/play_this"
  synth :piano, note: a, cutoff: b, sustain: c
end
"""

# on PYTHON3 use
from gpiozero import DistanceSensor
from time import sleep
from random import random

from pythonosc import osc_message_builder
from pythonosc import udp_client

# for one ultrasonic sensor use
#sensor = DistanceSensor(echo=17, trigger=4)

sender = udp_client.SimpleUDPClient('127.0.0.1', 4559)

while True:
      sensor = random()  # for test without ultrasonic only
      note = round(sensor * 80 + 20)
      cutoff = 55
      sustain = 0.5
      print(note,cutoff,sustain)
      sender.send_message('/play_this', [note, cutoff, sustain])
      sleep(1.0)

and [run Module (F5)] ( save the python code )
you should hear every second a different piano note ( for test ) and see the printline of python
try:
synth :supersaw, to get a theremin like sound (instead of PIANO )

[KLL]

use a pygame window and mouse click / drag in it
instead of a ultrasonic sensor...
see a black window and press ( and hold and drag ) mouse in it.

code: here

now a test using VNC android tablet touchscreen on that window was not funny because of the strange VNC mouse options ( screen scrolling)

[KLL]

also made a video about it: youtube