Right now, if you get a missed call alert from someone that's not in your phone book, you can see their number and call back, but there's no way to store that number to a new contact in your phone book. While it is possible to add the number from the missed call log, sometimes missed calls don't end up in the log, so it would be useful to have a way to add the number directly from the missed call alert.

I wanted to put a hypothesized reason in the issue title but am not confident about the cause... but to describe:

• was in EC, so possibly poor/no cell reception
• had removed the SIM card without rebooting

It'd be nice to see an error if the call fails, and i'm happy to try this in different combinations of circumstances to help narrow.

Sometimes, a field of the date or time (e.g. hour, minute, day of the month) will appear on screen as "0" instead of whatever the real value is. The text / string sent from the GSM module to the microcontroller appears correct when I look at the debugging output (I think) but somehow the microcontroller loses the value. This appears unrelated to the actual numbers / strings involved.

Similar to #3. Can the display show only serial characters, or can you specify per pixel? First or last character block could be dedicated to signal strength, or you can show a percentage in text.

Maybe you could rotate through different displays by clicking the up arrow, if that doesn't already do something.

Currently, text messages with international (non-ASCII) characters will get encoded by the sending device and show up on my phone as a string of digits. They should be properly decoded. Proper full international support would also require many additional glyphs / characters in the font but, regardless of that, we should decode the PDU messages.

The power of the phone (LED-Matrix-Variant) lasts for max. 48h after full charge of batter.

also important for airplanes

for in movie theaters

This has been mixed in (uncontrolled) with the "remove SIM card" error referred to in #1. So it's hard to diagnose without clear testing, but I seem to be unable to bring #s back up which have been dialed. If the recent called list is stored on the SIM card, that might make sense in relation to removing the SIM card without rebooting. Or when trying to call when there's been a SIM card error.

Is there onboard memory besides the SIM card? Could we sidestep the error by using that instead of the SIM card?

If you missed a call but haven't yet seen the missed call alert for it -- and then someone calls you and you answer, the subsequent missed call alert will show the number of the call you answered, not the one you missed.

just to be annoying, i'm going to create these issues because although I'm sure you've considered them and they're in the works, it's always good to hear that someone actually want the feature!

Can the display show only serial characters, or can you specify per pixel? First or last character block could be dedicated to battery life. Or it could scroll by a percent. I know calculating battery is not trivial...

When you remove the SIM card and then re-insert it, it's not automatically detected by the GSM module, leading to lots of problems (can't make calls, access the phone book, etc). You need to reboot (e.g. reset the microcontroller which will reset the GSM module) to re-detect the SIM card and use the phone again.

It seems that for the GSM module to automatically detect the SIM card, we need to use an eight-pin SIM socket rather than the 6-pin one on the current phones.

Another option would be to have a menu item that tells the microcontroller to restart the GSM module, which should allow it to re-detect the SIM.

Maybe it would be nice to add:

define PINNUMBER "YOUR_PIN_CODE"

and change the gsmAccess.begin into:

while (gsmAccess.begin(PINNUMBER, false) != GSM_READY) {
delay(1000);
}

It wasn't the most difficult part to figure out while building your DIY Cellphone. But it could help others.
Thanks again for the awesome documentation.

i want classy branding on this thing! Name it after a fruit or pastry...

The GSM.begin() function doesn't return until the phone connects to a network, so, failing that, it never starts up. It would be nice to still be able to, say, look up phone numbers, check the time, and use the alarm clock even without network connectivity.

Currently, if you get a text message from someone that's not in your phone book, you see their number and can reply, but there's no way to add their number to your phone book. There should be one.

If you get a text message or a phone call while you're in the middle of composing a text message or dialing a number, the phone number (and message) of your text or call is overwritten by the number of the person who just called or texted you.

There is an #include <GSM3Serial1.h> in the file cellphone.ino which I suspect makes use of the hardware uart 1, but this file is not available anywhere. It does compile as is, but the project seems to be using the software uart in my own similar project...

So, does this file exist, and does it make use of the hardware uart1 ?