Around '05 or so, the house we were staying in started beeping. Smoke alarm sounds, as usual. For almost a day we couldn't find the source. Contacted the owners -- they didn't know it either. They bought the house few years prior, so not much of a help.
Standing in the hallways listening at different angles, as the article says, didn't help. No Fable in '05 either.
So I had to improvise. Got a ~1 meter stick and two headphones (every headphone is a microphone, even if it sucks as a microphone). Plugged them into the stereo mic port, and started recording in Audacity. The phase shift between L and R pointed directly to the source. Took about 4 or 5 beeps to get the sucker.
Turns out, it was hiding above the ceiling tiles in the garage. My wife still tells this story to all her friends as one of my biggest life achievements. Everything I shipped, the companies I founded -- pales in comparison to finding a dead smoke alarm
chimpontherun
I didn't mention this in the article, but this isn't the first time my family has been driven almost spare by a mysterious, hard-to-track beep.
Our dog goes outside and hides in the lavender bush if a smoke alarm starts making a "I need a battery" noise.
So I went into this project with the attitude that I would like to solve this class of problem forever.
simonw
You can also solve this in O(logn) using a physical binary search:
1) Move half the boxes to another room.
2) Listen for a beep and determine which room the beep comes from.
3) Take the boxes in that room and split them in half again.
4) Repeat until one box is left.
tristanj
Ha! This reminded me of that old famous entry from bash org: "I can't find a server in my house. It responds to ping, but I can't physically locate it."
NitpickLawyer
Why didn't you time the interval between the beeps? Then when the next beep was coming up, just listen to a particular part of the room or set of boxes until you found it.
foo12bar
I’ve been trying to think of other uses for the system. I’m wondering about this:
What use could a teacher make of a locator system, if students could identify their location and desire to be singled out for a moment, by simply clapping once?
In a big auditorium, a spotlight could track over to the student, who could then ask a question.
And/or, directional microphones could zero in on the student so the question could be played on the PA system.
BubbleRings
> I think the most interesting part of this project is that I demonstrated it’s possible to give Claude Code ears
Of course it can analyze audio. I made it detect Marijn Frank saying a high pitched "Hallo" in a much better way that I could have done myself (subtitle matching), namely by frequency analysis, in the process learning how that works with librosa: https://marijnfrankzegthallo.nl
Confiks
There was a post on HN recently about a suspended string robot, and how it could manage different loads (picking up dirty laundry) depending on on where it was in the room.
Simon’s microphone configuration is very similar except instead of payload kg it would be affecting detection accuracy.
I wonder why the accuracy was an OOM outside the expected result (40cm vs 7mm)? Also using claps for calibration of unknown devices feels like a different approach to measuring distances between devices with a tape and solving the polygon. How many devices would be needed to self calibrate — 1x beep and Nx listening — instead of relying on smudgy claps? Or maybe every sound is smudged in a room filled with boxes?
gorgoiler
I like that tale! However, I've found that my Wire Fox Terrier has somehow trained himself to distinguish a smoke alarm beep from the plethora of beeps in the house and came upstairs today at 3am waking me up to tell me batteries were running out. He followed me around until I located the culprit and then went back to bed. Next time he'll have upped his game to tell me which device it is. He's a good boi!
FerretFred
Not related to the beep but if you still have natural gas (guessing based on the old carbon monoxide detector) you likely also want to get a simple plugin alarm that also detects natural gas in its natural un burned state.
Carbon monoxide is only produced when it's burned and builds up. And is obviously very dangerous. But a small gas leak building up over time or an oven pilot out and left on is not great for you either.
Make sure you place it relatively near the ceiling as it pools up there apparently. Saved my life during Covid lockdowns
comments (10)
Standing in the hallways listening at different angles, as the article says, didn't help. No Fable in '05 either.
So I had to improvise. Got a ~1 meter stick and two headphones (every headphone is a microphone, even if it sucks as a microphone). Plugged them into the stereo mic port, and started recording in Audacity. The phase shift between L and R pointed directly to the source. Took about 4 or 5 beeps to get the sucker.
Turns out, it was hiding above the ceiling tiles in the garage. My wife still tells this story to all her friends as one of my biggest life achievements. Everything I shipped, the companies I founded -- pales in comparison to finding a dead smoke alarm
chimpontherun
Our dog goes outside and hides in the lavender bush if a smoke alarm starts making a "I need a battery" noise.
So I went into this project with the attitude that I would like to solve this class of problem forever.
simonw
1) Move half the boxes to another room.
2) Listen for a beep and determine which room the beep comes from.
3) Take the boxes in that room and split them in half again.
4) Repeat until one box is left.
tristanj
NitpickLawyer
foo12bar
What use could a teacher make of a locator system, if students could identify their location and desire to be singled out for a moment, by simply clapping once?
In a big auditorium, a spotlight could track over to the student, who could then ask a question.
And/or, directional microphones could zero in on the student so the question could be played on the PA system.
BubbleRings
Of course it can analyze audio. I made it detect Marijn Frank saying a high pitched "Hallo" in a much better way that I could have done myself (subtitle matching), namely by frequency analysis, in the process learning how that works with librosa: https://marijnfrankzegthallo.nl
Confiks
https://neufangled.com/payload
Simon’s microphone configuration is very similar except instead of payload kg it would be affecting detection accuracy.
I wonder why the accuracy was an OOM outside the expected result (40cm vs 7mm)? Also using claps for calibration of unknown devices feels like a different approach to measuring distances between devices with a tape and solving the polygon. How many devices would be needed to self calibrate — 1x beep and Nx listening — instead of relying on smudgy claps? Or maybe every sound is smudged in a room filled with boxes?
gorgoiler
FerretFred
Carbon monoxide is only produced when it's burned and builds up. And is obviously very dangerous. But a small gas leak building up over time or an oven pilot out and left on is not great for you either.
Make sure you place it relatively near the ceiling as it pools up there apparently. Saved my life during Covid lockdowns
Melatonic