Hi HN,

As a weekend project, I hacked together a physical phone, a Raspberry Pi running Asterisk and Twilio, to let toddlers safely make international calls.

I’ve documented the setup in this write-up and published the code + Ansible playbooks on GitHub so others can replicate it.

I built this so kids of expats can easily stay in touch with family on other continents.

Would love feedback from anyone who’s worked on something similar or tries building this themselves!

writeup: https://wip.tf/posts/telefonefix-building-babys-first-intern... github repos: - https://github.com/nbr23/ansible-role-telefonefix - https://github.com/nbr23/allo-wed

I would love a way to make an IP phone that just lets my kids call their friends on their phones, and no-one else. I will take a look!

One sidenote is that the Twilio part is harder than it looks. Not because of technical factors, but because of the paid requirement. Twilio refused to take my money and upgrade me to a paid account, even though they forced me to go to their confusing KYC procedure, where they asked me many times to provide the same set of documents. Support was useless, it looked like an AI bot repeating the same thing, but this was before the widespread usage of AI bots.

Eventually I gave up and went to Telnyx, which had a better KYC process and actual humans behind support that could resolve any quirks with KYC. Apparently not being born where you live breaks a lot of the automation behind some of these processes, go figure.

I really like this... except you should add a special case for 911. I strongly believe that all phones, and anything that looks like phones, should be able to dial out in an emergency.

Obviously, this can raise its own problems -- you'll have to train the kids not to randomly dial 911! -- but you never know what circumstances might exist where someone in a panic reaches for the nearest phone.

This is using Twilio, but given there's an Asterisk server behind, you can actually use any VoIP provider that allows outgoing calls over SIP right? Depending on the country you live in and/or where you want to call, you might get simpler & cheaper options (although for emergency service if you want to have it, which I think is important unless there's an alternative way to call emergencies around, it's more complicated).

Nice project! Another route you might consider is flashing a small custom firmware on the Grandstream HT80x so the logic runs directly on the ATA instead of on the Pi/Asterisk side.

I wrote a tool that can extract and repack Grandstream firmware (https://github.com/BigNerd95/Grandstream-Firmware-HT802/tree...).

For example, I made a simple ARM patch that intercepts incoming caller IDs and triggers a bash script to decide what to do, in my case it checks a spam-lookup service and returns 0 or 1 so the ATA either rings or rejects the call.

For some reason I thought it was for toddlers to call other toddlers. I think if you were looking for a feature to add, it would be to let kids call their friends. Could lead to some cute moments :)

If you want this as a ready to go product - https://tincan.kids/ and disable 911 if international.

This is a great project writeup, I did something _very_ similar for my son. (HT802, asterisk, twilio, calling relatives) With all of the NAT involved I could never get sjsip to work properly so I ended up having to use the old sip module, but looking at yours makes me want to revisit it.

Once you have asterisk set up and running, it becomes easy to also set up all sorts of other extensions like "check the weather" / "tell a joke" / "check the train statuses". I put up some code for it here: https://github.com/mnutt/rotary

I love everything about this. I've often thought families that wanted to extend their network between trusted friends could set up a literal private branch exchange (aka PBX) with only their friends as fellow members.You have a way for people to call each other without handing kids a smart phone and can also avoid the inevitable costs and unwanted calls associated with real land lines.

I just setup the same HT801 but I used SIP-domains and twilio services/functions instead of SIP trunk and asterisk. I'll make sure to reply again once I have a write up.

Nice work!

Great work! Thank you for sharing this. I'm looking forward to making one just like this too.

Hardest part of this is getting a twilio account that actually works.

One of the worst service providers ive ever had to work with.

This is so cool! Mine is too young but I was planning to hack on something similar when they’re of age. Thanks for the inspiration!

>only permit calls to be made to an adult-controlled set of numbers timezones and “awake/asleep” schedules, to avoid calling Europe at their 1am prevent inbound calls entirely

This is interesting. Was there a serious issue while using a regular landline?

As a former toddler myself, I think that the worst I got up to was calling the radio station and giving bad traffic tips.

My overseas family had such a long number, stored in a book in my grandmothers handwriting, that theres little chance I would have connected and woken them up.

Is this designed to counter a specific threat model?

uhmm...

>>> As a weekend project, I hacked together a physical phone, a Raspberry Pi running Asterisk and Twilio, to let toddlers safely make international calls.

how often do toddlers make international calls???