So guys iam introducing all of you reading this blog to a new way of reusing our old mobiles phones which we are not using now may be due to it ithe emergence of new high spec Smart phones.We all have our old mobile phones in our home may be the battery will weak or display wont be much clear,may be small ,small defects will be there.Regardless of all this if calling facility is still available in your phone wheather its keypad or smart phone(Also SIM card).TRUST ME YOU CAN CREATE WONDERS WITH THIS.So guys lets get started,
First of all I was trying with old phones camera to reuse but while I opened the phone I came to understand it can be never done ,then I was exploring its each and every part. After a day or two an idea stroke me.That is whenever a phone rings ,ring means sound,
Sound means vibration ,vibration due to the voltage available at the speaker terminals .So why cant we tap the this signal from the speaker out to a microcontroller to process it and make an action accordingly for automations or other purposes.That is whenever we try to ring the cell phone a voltage rise occurs at the speaker terminal we tap this voltage rise ,and based on the number of rings that is number voltage ups and down we can create as many events for automating as many devices(If sufficient signal or voltage is not available at cell phone speaker terminals you can use the vibrator,and I prefer using the cell phone vibrator terminals and make sure you have turned on the vibration mode in the phone call settings)
1.First of all take an old phone remove its back cover ,unscrew it ,remove the back layers go to the section where speaker and vibrator is placed .
2.Take a multimeter connects its probe to the phones speaker/vibrator terminal. Turn the knob to DCvoltage on multimeter and check the voltage.you can see 0v.And give a call to the old phone from another phone you can see the voltage rises and drops.so if u give a call ,voltage rises hence this can be utilized for our job.
3.Now solder two wires across the terminals of the speaker the wires should have min length ,so that even if the phone back layers are closed ,the wires are available outside to tap the signal.
4.Now after soldering close the back layers ,
5.And again connect the multimeter probes to the two wires and give a call to the phone to check our soldering and connections are fine.
6.Now for easiness of the project we can use an Arduino for processing ,So we take an Arduino and connect its A0 pin to the positive terminal and Ground to the negative terminal of the wires
7.And take the example the program in ArduinoIDE for Analog voltage check and upload the program to the Arduino.And make a call to the phone and start the Serial monitor in the Arduino ide ,you can see the voltage outputs.
8.So our job is 90% done ,Now download and upload my code for Various device activations.Connect the device to P!3 on Arduino ,and by making changes in my code
you can put as many as devices as well as on any pins.Here is my code link-https://github.com/stijojoseph/oldmobile-to-gsm
9.you can can connect out of P0 to P13 pins in Arduino and connect relay and automate home apppliances or devices as your wish
Hope you have good time reading the blog.The same project and video I have published on my youtube channel @Electrical Coder as it was getting good response there I thought of sharing it with my community members in here too .Anyways Happy and Happy new Year .This is my Tutorial Video for the Project