Contents
This note is in group Technology, sub-group My Beep-BRRR pages. Mail me if you are interested in porting this into a product. I may be, too!
2024 12 11 – Pivot division in practice
This describes my new «pivot division» (I believe, invented by me) routine in function on an old analogue microamperemeter which is fed a 500 Hz PWM signal. Also so 219:[Signal Processing], point 7, «Fraction and inverted fraction: a name for it«.
Download and run from https://www.teigfam.net/oyvind/blog_notes/219/logs/2024_12_11_v09441_y720.mp4. So this url also is linked up at Stack Exchange, Signal Processing.
2024 11 18 – Beep-BRRR using smart home to extend its functionality
The user sent me the above video (1.8 MB). The door bell is heard. The Beep-BRRR detects it and issues an alarm output signal. This «presses» the button on a Plejd button unit, via some electronics I made. Plejd uses Bluetooth. The button is configured to send an «on» message to a mains output unit (not seen, below the table). After some delay I cannot explain this so happens. A 5V USB adaptor is plugged into this. When my knocker alarm unit is powered it at first knocks and blinks, after some three seconds it only flashes. Later on, both the Plejd switch and the Beep-BRRR must become reset by hand individually at the Plejd button unit and at the Beep-BRRR.
This system is described at 261:[Architecture D].
Below we see how it works, on the lab bench:
The movie is about 48 MB. Here is the text in it. With only capitals available in iMovie headers «kHz» is «KHZ»:
| REMOTE ALARMING ØYVIND TEIG, NOV2024 0-4 KHZ PER SPECTRUM ON DETECTING THE FIRE ALARM SOUND WHEN PLAYED FROM THE COMPUTER BEEP-BRRR «PRESSES» THE PLEJD BUTTON WHICH SENDS OVER BLUETOOTH TO PLEJD OUTPUT UNIT WHICH POWERED UP MY KNOCKER/ALARM UNIT THEN RESET BY HAND ON PLEJD BUTTON: THEN BEEP-BRRR LATER WAS RESET WITH THE BUTTONS |
2023 02 12 – Prototype in field test
I connected the prototype Beep-BRRR (Beep-BRRR-proto) in the bedroom where the final version is going to reside. I had recorded the sounds from the building’s central fire alarm and one from the door bell. At first I tested with the sounds coming from my iPhone. I had recorded them at my place, with sound from proper speakers.
The door bell sound gave an iPhone alarm nearby. The real door bell, some 10 meters away, also gave an alarm. But not with the door to the sleeping room closed.
However, the fire alarm sound was detected, also through a closed bedroom door, when I moved outside it with my iPhone, into the living room where several people were playing a game, with no message from me for them to keep quiet. Beep-BRRR! I assume the real sound from the real sounder would be decades of dB louder, hopefully giving a good margin.
The photo shows how I connected the Beep-BRRR to a Bellman & Symphon BE1370 Alarm clock. It’s actually two merged photos indicating that it certainly behaves 🙂 (Standard disclaimer)
So, I’m on my way!
2023 01 09 – Detecting a sound amid noise
The movie is about 37 MB. Observe that the hardware here is the XMOS xCORE array for Beep-BRRR. As of 2024 this is only kept for reference, while I have moved on with Beep-BRR2. The text (as graphics) appearing in the movie is this:
| Now playing the locally recorded fire alarm sound from the computer.This is called «sound B». This sound once was recorded on site while the fire detection and warning system was tested. This same sound has also been recorded on the Beep-BRRR by playing it from the computer. There it is one of several sounds. |
| «B» = Fire alarm Detected in the presence of ambient «noise». Spectrum output from Beep-BRRR seen on the scope, but removed by button before the fire alarm was started at the computer (waiting for a more «noisy» part from the radio). Design, algorithms and coding by Øyvind Teig, Trondheim, Norway |
2022 12 01 – Detecting two sounds
The movie is about 41 MB and shows the state of this box as of 01Dec2022. The text in the movie is this:
| «B» = Fire alarm «R» = Piano «Aldrig» @ 2:09 by Benny Andersson Max 6 sounds recorded in the box and then their meta-data is stored in non-volatile FRAM memory Design and algorithms by Øyvind Teig, Trondheim, Norway |