I am working on a idea for some remote controlled equipment via phone
Initially I thought about data over sms but then found DTMF solutions as pictured
I am looking to do some kind of remote home automation like adjusting thermostat or opening garage door via text or call
I also located a carrier called Truphone that provides global phone coverage through their own network and allows free incoming calls inside the US and UK I verified with their rep at the call center that you pay upfront for the sim card ($20) and some prepaid minutes (the minimum) and it can sit dormant for 180 days at a time and only needs 1 call or text to keep the account alive with incoming is always free.
Does anybody have sujestions on weather to go with a cheap DTMF solution or something arduino or Pi based with a virtual operator asking for button presses?
Here is the link to the provider if it can help someone else looking for a super cheap inbound only gsm project
https://www.truphone.com/us/consumer/sim/
Text messages are cheaper than voice calls, and you'd need to be making voice calls to transmit DTMF.
Cell phones don't use DTMF. If you hit a button while talking the other end doesn't hear DTMF like with land line phones. You'll have to create an app or external device that plays DTMF into the cell phone voice connection.
Voice calls through a cell network are digitized and compressed. Your DTMF could look like background noise and get filtered out.
>>1018691
Does it have to have a phone on the other end? You could get a raspberry pi and control stuff over SSH from yhe internet. Instead of using a cellphone, you might use a GSM module, which is a cellphone in a handy hackable format.
It might be best to use a GSM module and send it SMS messages to control what you want to do. For best results use encrypted text messages
>>1018697
Cellphones do DTMF, if they didn't 'press 1 now to speak to a representative' wouldn't work
cool
>>1018691
build your bomb somewhere else.
>>1018763
Do you know how handy it is to lock my door in Florida from Ohio after I realized I forgot to? From the taxi in the middle of a wooded area. The point is, this stuff can be useful.
>>1018697
>Cell phones don't use DTMF.
yes they do, wtf nigga
do you even gsm?
>>1018774
And then some old lady calls your device causing it to go haywire, causing your water heater to overflow and your doors to unlock
What about Nokia's FBUS
The principal I guess I was going for is with this sim and provider you can essentially have a always on ready gsm device that can take incoming calls and sms for free
I guess the most useful implementation I can think of would be a a device you call into and it has a voice prompt or text to speech to read your data or accept DTMF commands.
I wonder what would be involved in having it auto answer so you would be able to just blast a command at it right from the dialer with pauses and then just listen for a conformation
Ex. android phone contact set to xxx-xxx-xxxx,1234,12
comma symbolizing wait
>>1018789
You do run the risk of somebody misdialing your experiment and hopefully you have a failsafe or security
>>1018763
That would be some Die Hard with a Vengeance shit with some multi chemical mixing remote controlled bomb
>>1018691
Worst case you could just hook something to the ringer and vibrator and have a relay that can do 2-3 things only. Having text to vibrate and call to ring you have at least to bits of data right there.
Not to shill, but have you looked at twilio or similar? DTMF has a retro appeal though. For extra street cred, implement V.90 and do a handshake every time.
>>1018691
A msp430 + a GSM module communicating over UART, SPI or I2C with the micro controller. Then just read the numbers over the serial link with AT commands.
>>1018774
Umm, yeah. Right.
https://www.youtube.com/watch?v=_CQA3X-qNgA
>>1018691
dont they teach you this jehad school?
>>1018821
You can make simpliest fuse by wrapping copper wire around head of a match and connect it to 12v battery. Put your phone remote to act as a switch, put some explosives made from fertilizer and you're ready to join Al-Queida. It's not really multi chemical mixing high tech thing.
>>1019636
>wrap a match with copper wire
Whut? How about advising them to make a short coil of copper wire with a few wraps at the tip of a pair of needle-nose pliers?
