Summary of Make Your Own Smartwatch From An Old Cell Phone
This article details repurposing an old Nokia 1100 cell phone into a smartwatch. The process involves scavenging components like the LCD screen, vibrating motor, speaker, and protective cover. The PCF8814 LCD is connected to an Arduino Uno using specific pinouts and resistors for voltage regulation before integration into the watch form factor.
Parts used in the Smartwatch Project:
- Nokia 1100 cell phone
- LCD screen (PCF8814 model)
- Vibrating motor
- Small speaker
- LCD protective cover
- Arduino Uno
- Ribbon cable wires
- Hot glue
- Breadboard
- Resistors (1.8 kOhm and 3.3 kOhm)
Step 1
Scavenging Parts
What I’d like to do for this crazy/ambitions project is turn an old cell phone into a smartwatch. So obviously an old cell phone is required. The primary reason for this project is simply that I had an old cell phone laying around and wanted to find a creative way to repurpose it. The one I had is a Nokia 1100, but most other old cell phones would work, so long as you can find the schematics for the LCD online. Taking apart the 1100, there weren’t too many scavenge-able parts to choose from. First and foremost, there was the LCD screen, then I was also able to extract a vibrating motor, a small speaker, as well as a protective cover for the LCD. What you’re able to scavenge really depends on what type of phone you have, and how old it is. The older the phone, the more scavenge-able parts you will find.
Step 2
Figuring Out The LCD
Without a working LCD, we have no project, so I need to figure out how to get it working outside of the phone. The first step is to see if I can find a schematic for it online. Doing a search for “Nokia 1100 LCD”, I was able to find out a ton of information about it. I found that the LCD model number is PCF8814. I was also able to find a schematic that listed the pinouts.
This is a view from the back side of the LCD, so Pin 8 is on the far left when looking at the back. There are 9 pins, but one is unused, leaving 8.
- LED (Positive – 3.3v)
- VDD
- VDDI
- SCLK
- SDA
- GND
- CS
- RES
The pins on the LCD are very small, so in an effort to make them easier to connect to, I soldered wire from a ribbon cable to each pin, and then hot glued it all into place. So now I can connect each of the wires to a breadboard to make it easier to work with the LCD.
Step 3
Driving The LCD
- LED > 3.3v (Moved to Pin 8 for custom on/off control)
- VDD > 3.3v
- VDDI > 3.3v
- SCLK > Pin 13
- SDA > Pin 11
- GND > GND
- CS > Pin 10
- RES > Pin 12
Here is the connection diagram:
Read more: Make Your Own Smartwatch From An Old Cell Phone
- How do I find the schematic for my old phone's LCD?
You can search online for terms like your phone model plus LCD, such as Nokia 1100 LCD. - What is the model number of the Nokia 1100 LCD used?
The LCD model number identified in the project is PCF8814. - Which microcontroller was chosen to drive the display?
An Arduino Uno was selected for prototyping, with plans to use an Arduino Mini later. - Why were resistors added to the connections?
Resistors were added to prevent the Arduino from burning out the LCD. - How many resistors of each type were used?
The project required four 1.8 kOhm resistors and four 3.3 kOhm resistors. - Can other old cell phones be used for this project?
Yes, most other old cell phones work as long as you can find the schematics for the LCD online. - Does the age of the phone affect the parts available?
The older the phone, the more scavenge-able parts you will typically find. - How were the small LCD pins made easier to connect?
Wires from a ribbon cable were soldered to each pin and then hot glued into place. - Where should the LED pin be connected on the Arduino?
The LED pin connects to 3.3v but was moved to Pin 8 for custom on/off control.
