Author Topic: Help Grandma Hear Her Doorbell!  (Read 4920 times)

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Offline Salome2Topic starter

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Re: Help Grandma Hear Her Doorbell!
« Reply #50 on: October 03, 2024, 03:23:46 am »
Mia, yes it would be helpful, if you did share this!
« Last Edit: October 03, 2024, 03:29:33 am by Salome2 »
 

Offline JoeyG

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Re: Help Grandma Hear Her Doorbell!
« Reply #51 on: October 03, 2024, 04:16:12 am »
DTMF Tone Detection on PIC18

https://sites.google.com/site/hobbydebraj/goertzel-algorithm-dtmf-detection

It discusses the MIPS required.  Extract
MIPS requirement: -

PIC18F4520 runs at a max frequency of 40MHz and internally, the clock is divided by 4 to get 10MIPS.

The implementation of Goertzel acquires a buffer of 100sample, sampled at a rate of 5908Hz.

Time to acquire 100 samples = 100 * (1/5908) = 16.92millisec
Time to perform Goertzel decoding (measured by toggling a GPIO on oscilloscope) = 9.40millisec
MIPS required = (9.40/16.92) * 10 = 5.55MIPS.

Also
https://www.embedded.com/the-goertzel-algorithm/

Also
https://netwerkt.wordpress.com/2011/08/25/goertzel-filter/
PIC12 in  assembly language
https://www.instructables.com/DTMF-Touch-Tone-Decoder-Using-Microchip-PIC-Microp/
 
The following users thanked this post: Salome2

Offline Salome2Topic starter

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Re: Help Grandma Hear Her Doorbell!
« Reply #52 on: October 04, 2024, 09:26:00 am »
JoeyG, Thanks a million for presenting working C code to do Goertzel!

The highest freq. in touchtone is 1633Hz while my freq. of interest to detect  is 2kHz and I trying to understand how to make the c code modification without success.

A major consideration in the doorbell detector is battery usage. The 16F18456 doesn't have any hardware multiplier, which makes it 10x slower to do math than using any 18F MCU, and so the 16F18456 would use 10x the power and 10x the time?
« Last Edit: October 04, 2024, 09:33:01 am by Salome2 »
 


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