I was looking for a cheap and easy way for my projects to call me on my phone. Since pulse dialling is simple and requires the least components, I decided to go for that approach.
In my case, I gutted out a cheap phone and housed my Arduino inside. If you do not wish to open up or destroy any phone, you can just splice the phone line going to the phone and connect your Arduino there. The diagram below shows how everything is connected.
The Arduino's job is very simple. It just needs to count the pulses based on the phone number to be dialed and output it to the relay.
The code stores the phone number in an array, then uses a FOR loop to dial each digit. The comments in the code will help you configure your dialer. Most people will just need to change the phone number for it to work.
You can get the code here.
I hope you've found this tutorial useful. If you have any comments or feedback you can leave them below and I will try to answer to the best of my ability. Happy hacking!