esp32intdelayonly.zip

Updated delay program with small code fixes and tabbed source, better comments

x-zip-compressed - 3.18 kB - 09/13/2021 at 06:36

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esp32intdelayvox.zip

Updated delay with VOX code. General tidy up and automatic calculation of optimum memory use and sample rate. Also set up with tabs for readability and more comments. Some small non-fatal bug fixes.

application/x-zip-compressed - 10.23 kB - 09/10/2021 at 05:54

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VOXtiming1.JPG

Basic timing diagram for time shifting VOX

JPEG Image - 41.23 kB - 12/18/2018 at 02:33

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esp32svox.JPG

Revised hookup for ESP32S with VOX adjustment pot

JPEG Image - 46.81 kB - 12/16/2018 at 02:04

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repeater_test.mp4

Test of the repeater. Note you can see the signal strength meter on the receiver on the left show the incoming transmission. The transmitter on the right shows it transmitting the start beep almost immediately (which we are hearing through a separate CB receiver off camera) and then we hear the delayed transmitted audio about a second later. If you look closely, you can see the LED on the ESP32 light up as well.

MPEG-4 Video - 3.17 MB - 12/13/2018 at 21:34

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buffer_filter.jpg

Buffer and low pass filter for use on both input (anti-aliasing) and output (step smoothing) of the ESP32 based delay. Assumes a minimum 20000/sec sampling rate.

JPEG Image - 106.76 kB - 12/10/2018 at 04:23

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2khzinputraw.jpg

2kHz sine wave line level input (+/- 1.5V) before filtering and delay. This is the maximum input the ADC will take without clipping.

JPEG Image - 269.43 kB - 12/10/2018 at 02:43

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DACunfilteredoutput.jpg

2kHz sine wave output from the ESP32. Sampling rate was 32000,/second, the input was filtered with a 9.6kHz low pass filter.

JPEG Image - 123.19 kB - 12/10/2018 at 02:43

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delayedandfiltered.JPG

Final 2kHz sine wave output after post filtering with a 9.6kHz low pass filter. Note that the original input line level has been preserved. It looks good!

JPEG Image - 24.89 kB - 12/10/2018 at 02:43

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esp32echo.ino

A program to insert an echo into realtime audio. Customisable delay and intensity.

ino - 2.38 kB - 12/04/2018 at 02:25

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Sample_Results_audio.amr

Audio sample. You are hearing the original voice audio, then the result after going through the repeater system. Recorded using a phone sound recorder! Quite intelligible, under the circumstances!

amr - 10.38 kB - 12/04/2018 at 02:00

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