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I have several points on this: "...yet there isn't a project like that" Not exactly. There are several Arduino based phones like the DIY Cellphone by David Me

by rawfan 10y ago

I have several points on this: "...yet there isn't a project like that" Not exactly. There are several Arduino based phones like the DIY Cellphone by David Mellis. I have an improved version of that right here. "Open Source / Open Hardware" All open phone projects have the exact same problem. The core component, the baseband (which is basically the phone) is a complete blackbox. AFAIK that's also true for the SIM800 used here. So arguing security is a bit dishonest. "Price" I'd say the price calculation is extremely optimistic. You'll only get that price if you buy the parts in bulk. Especially the PCBs. Anyways.. cool project!

Nexxxeh 10y ago
I wouldn't have said dishonest. The only access the baseband running on the SIM800 has to the main processor (Pi) is via the Pi's UART. It's completely different from the "read and write directly to shared memory" access the baseband that your average Android potentially has. If you encrypt your SMS on the Pi and send it, ths SIM800 has no access to the keys for decryption, for example. I'm guessing you're talking about his price calculation for the $27, right? A bit further on he does say: >In total, it should be 50$ or slightly more. >Also, price falls quickly if you're assembling one or two more phones for your friend, too - eBay sellers can make discounts when you buy more than XX$ or "make an offer", and PCBs are cheaper (you won't get less than 3 pcs of PCBs in any of usual board houses, so you have to pay extra even if you need only one board - you'll still get two more) I don't think that's too far off and may be a bit pessimistic. The only component you can't bulk buy easily and cheaply is the Pi Zero as it's STILL one per customer. ABut none of the parts are expensive in single units either, except relatively speaking the PCBs. Which are non-essential because you could literally breadboard it. If you're interested, he did an AMA on Reddit earlier.
- saycheese 10y ago
  Do you have a link to the AMA on Reddit?
  - deutronium 10y ago
    https://www.reddit.com/r/raspberry_pi/comments/5nwmfx/im_making_a_pipowered_opensource_mobile_phone/ https://www.reddit.com/r/raspberry_pi/comments/5nwmfx/im_mak...
BuuQu9hu 10y ago
The Osmocom Baseband project is open source software for GSM basebands: https://osmocom.org/projects/baseband https://osmocom.org/projects/baseband

by rawfan 10y ago

Nexxxeh 10y ago

I wouldn't have said dishonest. The only access the baseband running on the SIM800 has to the main processor (Pi) is via the Pi's UART. It's completely different from the "read and write directly to shared memory" access the baseband that your average Android potentially has. If you encrypt your SMS on the Pi and send it, ths SIM800 has no access to the keys for decryption, for example. I'm guessing you're talking about his price calculation for the $27, right? A bit further on he does say: >In total, it should be 50$ or slightly more. >Also, price falls quickly if you're assembling one or two more phones for your friend, too - eBay sellers can make discounts when you buy more than XX$ or "make an offer", and PCBs are cheaper (you won't get less than 3 pcs of PCBs in any of usual board houses, so you have to pay extra even if you need only one board - you'll still get two more) I don't think that's too far off and may be a bit pessimistic. The only component you can't bulk buy easily and cheaply is the Pi Zero as it's STILL one per customer. ABut none of the parts are expensive in single units either, except relatively speaking the PCBs. Which are non-essential because you could literally breadboard it. If you're interested, he did an AMA on Reddit earlier.

saycheese 10y ago
Do you have a link to the AMA on Reddit?
- deutronium 10y ago
  https://www.reddit.com/r/raspberry_pi/comments/5nwmfx/im_making_a_pipowered_opensource_mobile_phone/ https://www.reddit.com/r/raspberry_pi/comments/5nwmfx/im_mak...

BuuQu9hu 10y ago

The Osmocom Baseband project is open source software for GSM basebands: https://osmocom.org/projects/baseband https://osmocom.org/projects/baseband