Make a regular phone number you can call to talk to ChatGPT.
I'm not telling you my number so you'll have to follow the instructions below if you want to try it live.
IDK man, it seemed like fun. It's a quintessential "gluing APIs together" project. OpenAI has speech-to-text, chat, and text-to-speech APIs already; I just needed to attach Twilio.
Of course that was before I realized how much pain I was going to have trying to convert the audio streams (mulaw to/from Twilio, mp3 to/from OpenAI). But I got there in the end.
(Pro tip: when trying to convert Twilio's mulaw stream with ffmpeg, you need to explicitly specify the sampling frequency explicitly using -ar 800, and the -ar 8000 bit needs to come before the -i input parameter in the CLI.)
This is a Node.js app.
node set up.npm install to get dependencies.You need to be able to expose a port on your machine to the wider internet. Tailscale funnel works well if you have Tailscale set up already, or alternatively Twilio's docs suggest ngrok. The code assumes you'll have a domain name which allows connections over the standard port (443), which either of the previously-mentioned services will provide; if that's not the case for you the code will require tweaking.
DOMAIN.txt in this directory.You need a Twilio account with a phone number. They have a pretty generous free trial which is sufficient for demo purposes (at 2¢/minute, the $15 trial credit goes a long way).
your-domain-here is the domain mentioned in the previous part.You need an OpenAI account, with billing enabled.
Finally you need ffmpeg.
node call.js will run the app and wait for your webhook on port 3000. Make sure you're running Tailscale funnel or whatever so that the wider internet can talk to that port.
Then call the number and just talk. You'll need to wait 3 seconds after speaking for it to recognize that you're done and start responding, and responses themselves will also take a couple seconds to begin.