3 ms·

SIM800L costs $2. It supports GSM (AT commands - dialing, SMSs etc.) and GPRS (both PPP and a direct TCP connection to a hostname and port). Regarding USB dong

by Jenda_ 7y ago

SIM800L costs $2. It supports GSM (AT commands - dialing, SMSs etc.) and GPRS (both PPP and a direct TCP connection to a hostname and port). Regarding USB dongles, I've been running Huawei E3131 with RPi. I needed to put +5V directly onto the pin header, but maybe now with the USB-C RPi4 the power should be stable out-of-the-box. I have heard rumors that the modem freezes after a while, but I've never ran it for longer than a few days. I'd recommend either investigating whether you can hard-reset the modem with software (cycling the USB power) or even putting a watchdog that will cut power to the entire RPi. Regarding power consumption, SIM800L is fine in idle, a few mA. However, USB dongles AFAIK do not support power save and they will eat ~100 mA all the time, which might be a significant portion of your power budget.

nevi-me 7y ago
Wow! Thanks, I saw SIM800L but thought that it's maybe some add-on, because the Pi/Arduino GSM components I normally see do cost more than a Pi 3. The prices that I'm seeing are an equivalent of US$10, but that's good enough. I'll buy one and try it out. I see it only supports GPRS though, are there other cheap devices that support faster connections like EDGE/3+G? If one wants to send things like images from a camera, a faster connection would be more reliable.
- hutzlibu 7y ago
  With 3+G you will need more power.. and a faster connection would not be more reliable ... just faster. So if you want to have a real-time video-stream, than you need that. But for a security cam, gprs and low resolution images should be fine.
  - mentat 7y ago
    I believe the Narrowband stuff that Twilio's starting to roll out it's meant to address this.
mdorazio 7y ago
Keep in mind that most networks in the US are sunsetting GSM/GPRS within the next two years if they haven't already. Building anything dependent on this is a tricky proposition.

by Jenda_ 7y ago

nevi-me 7y ago

Wow! Thanks, I saw SIM800L but thought that it's maybe some add-on, because the Pi/Arduino GSM components I normally see do cost more than a Pi 3. The prices that I'm seeing are an equivalent of US$10, but that's good enough. I'll buy one and try it out. I see it only supports GPRS though, are there other cheap devices that support faster connections like EDGE/3+G? If one wants to send things like images from a camera, a faster connection would be more reliable.

hutzlibu 7y ago
With 3+G you will need more power.. and a faster connection would not be more reliable ... just faster. So if you want to have a real-time video-stream, than you need that. But for a security cam, gprs and low resolution images should be fine.
- mentat 7y ago
  I believe the Narrowband stuff that Twilio's starting to roll out it's meant to address this.

mdorazio 7y ago

Keep in mind that most networks in the US are sunsetting GSM/GPRS within the next two years if they haven't already. Building anything dependent on this is a tricky proposition.