Episode: 2217
Title: HPR2217: building a new voice input device
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr2217/hpr2217.mp3
Transcribed: 2025-10-18 15:49:11

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This in HPR episode 2,217 entitled Building a New Voice Input Device.
It is hosted by Genre and in about 6 minutes long and carrying a clean flag.
The summer is a bunch of different about putting a little computer into a phone.
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Hello HPR listeners, my name is Jezre and I like to make computers that do stuff.
Recently I finished putting together a computer to handle and process microphone input and I thought
it would be a great idea to use that computer to record an episode of HPR.
The case of this computer is a fairly attractive brass and wood wall mount rotary dial phone.
The computer inside of this rotary dial phone is the chip $9 computer from next thing code.
The chip is running Debbie in 8 with a 4.4.13 kernel.
The handset of the phone needed to be adjusted and changed so that the microphone was more useful with this computer.
The default microphone of a mid-70s rotary dial phone doesn't connect very well to a computer.
Fortunately I had a nice desktop microphone that I could take apart and solder and glue in place in my handset.
Unfortunately before I did such a thing my puppy decided to chew on the microphone and it resulted in some less than high quality audio.
But in my last HPR episode my audio was absolutely terrible.
I did also light a boat on fire two or three times and then how do you not share that?
So even if it's bad audio share the story.
Once I had replaced the microphone in the handset of this phone I needed to solder two RCA jacks to the handset cable.
The chip computer itself has three RCA jacks coming out.
Left and right audio as well as video.
Now I had the handset set up for audio and microphone out.
The chip in a really display of genius was designed in such a way that it's physically possible to hack the hardware and convert video out into my computer.
This requires a little bit of soldering and a little bit of scraping and very, very good magnification.
I didn't have any magnification so I just kind of winged it and was amazingly surprised when it worked but it did work.
So I now have hanging on the wall is a case of a rotary phone with a computer inside of it and it has audio coming out to the handset and it is accepting microphone input from the handset.
My current usage of this phone required hacking some software and a bit more hardware hacking.
On the hardware side I wired the cradle that the handset gets put on when hanging up the phone to connect to the GPIO on the chip.
This means that when I pick up the handset a signal is sent to the computer and when I hang up the handset a signal so there's a computer and I can then do things at that time.
For example this computer is running blather for speech recognition. I pick up the handset chips as handset is up launch blather and exit blather as soon as a verified command has been spoken.
So I pick up the handset blather starts I say lights on or lights off and then the lights in my place turn on or they turn off.
And then I hang up the phone. That's how I'm currently using it. Well actually that's how I'm using it when I'm not recording an HPR episode.
In order to record this episode I SSH into the chip computer disabled the system D service that is watching to see if the cradle has been lifted up or down and then ran a record which is a command line audio recorder that is part of also you till.
Or maybe it's also tools. Check your distro it might be different from there on a laptop or my phone or whatever I have SSH installed on I can connect to this phone start recording and then control C stops recorded.
Then I can use SCP to move that audio file to another computer edit using audacity or some visual audio editing program and then package it all up and send it off to HPR.
And as a matter of fact I think I'm going to do that right now.
Oh no I'm not. Firstly I'm going to do is I'm going to thank NY Bill for sending me a wonderful soldering pen that this project would not have been able to be created without NY Bill.
Thank you. HPR listeners. Thank you. Anyone who's ever taken anything, taken it apart, put it back together a little bit better.
Thank you. You are my inspiration. Now I have some SCP and audio editing to handle. Have a great day.
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