Hi,
I've acquired an old car phone and am trying to re-purpose it as an in-car control panel, capable of switching things like fog lights, audio amplifiers, etc as well as displaying information such as temperatures, voltage, etc on the built in LCD.
I plan to do this with an Arduino Uno (outside of the phone which the phone handset will plug into) which will output a small voltage when one of the phone buttons is pressed which will then activate a relay.
I feel this would be relatively easy to do if it was to be built from the ground up (however I am quite new to arduino so this may not be true) but trying to incorporate it into the phone has me stuck.
The main issue I'm hoping someone can help me with is how to run the LCD as well as the 18 buttons with only the 8 wires found in the phone jack. If anyone has any ideas/insight into how this could be done I'd really appreciate it.
I have attached a photo of the phone as well as it's internals.
Thanks in advance,
D_D
I think the easiest way to do it will be to rip out all the internals and put a Micro, Nano or Mini Arduino in there. With a screen you buy off-the-shelf you will get the information required to interface to it.
Since I've made a lot of projects with custom circuit boards, I would make my own PCB which holds the buttons. You will probably find that the buttons are relatively simple contacts or maybe you can put a modern tac switch under each one.
MorganS:
I think the easiest way to do it will be to rip out all the internals and put a Micro, Nano or Mini Arduino in there. With a screen you buy off-the-shelf you will get the information required to interface to it.
Since I've made a lot of projects with custom circuit boards, I would make my own PCB which holds the buttons. You will probably find that the buttons are relatively simple contacts or maybe you can put a modern tac switch under each one.
Thanks a lot for your help.
I've decided to go with your idea to put an arduino micro inside the phone and will use a nokia 5110 display and a simple of the shelf 4 button pcb with 1 button cut off to fit the housing.
Agreed. The existing internals are useless - you have no idea what it's doing, and it's for a very different purpose anyway.
I guess you're going to need a second Arduino to do the actual controls: one in the phone that reads the buttons and controls the LCD, the second one is sitting somewhere on the other end of the curled wire and which does the actual reading of sensors and switching of the lights and whatnot. They can communicate over Serial, with your phone Arduino sending commands to the controls Arduino, and receiving sensor data back.
Do make sure you have a good power supply for them, as car electrical systems are notoriously noisy and prone to voltage spikes.
wvmarle:
Agreed. The existing internals are useless - you have no idea what it's doing, and it's for a very different purpose anyway.
I guess you're going to need a second Arduino to do the actual controls: one in the phone that reads the buttons and controls the LCD, the second one is sitting somewhere on the other end of the curled wire and which does the actual reading of sensors and switching of the lights and whatnot. They can communicate over Serial, with your phone Arduino sending commands to the controls Arduino, and receiving sensor data back.
Do make sure you have a good power supply for them, as car electrical systems are notoriously noisy and prone to voltage spikes.
Thank you for the input! I'm new to this whole process so the help/advice is much appreciated.
I was planning to have the arduino in the phone give out a voltage when a button was pressed which would then switch a mechanical relay. Do you think having a second arduino would be better than this?
Also any recommendations in the power supply area??
I've just had a quick research about serial to serial communication between arduinos. Please correct me if I'm wrong but would doing this allow me to output/input more than 6 values from the phone? (6 being the number of wires within the curled wire minus power and ground)
You can move any amount of data over Serial. You can even program an Arduino over Serial! (that's the regular way even). No restriction there.
Serial needs three wires. Two data, TX and RX, plus GND. For your phone Arduino you'd need a fourth wire: power. That's it, the other two wires you have are spares in this case.
You could produce different voltages for your keys - 18 levels in all - and do an analogRead on them. Probably much easier to wire them in a matrix and have an Arduino read them (a Pro Mini will fit easily). That same Arduino will then drive your LCD display, displaying temperature or whatever you want on the LCD.
The "master" Arduino could be hidden somewhere in the dash or the centre console, and that one would read the sensors and drive the lights. Then either on request, or on schedule, it would send the data to the handset Arduino. The moment a button is pressed, the handset would send a command (could be as little as a single character) to the master telling it which lights to switch on/off etc.
