Some LCD screens from old cell phones have gained popularity among electronic enthusiats. They are easy to interface with a microcontroller and consume very little power. Best of all they come free or at very little cost. One common problem with these screens is how to connect them to your project. They usually have very tiny contact connectors that are hard or sometimes even impossible to solder to. Here is a nice trick I learned by trial an error how to connect a Nokia LCD to your breadboard without soldering.

For this purpose you will need to search your junk box for a flex cable with the same pitch as your LCD connector. For my Nokia LCD this happens to be a 1mm pitch cable that I found in an old CD-ROM drive. Similar cables can be found in other computer equipment like printers, scanners, fax machines.

IMG_0427.JPG

Next steps are :

– carefully remove the blue plastic plates that are usually glued to each end of the cable.

– cut the flex cable along to the desired number of wires. My LCD connector has 9 pads so I cut the cable to 9 wires. Use a sharp knife or blade, if using scissors be careful not to damage any wire

– split one end of the cable and attach crimp terminals (female or male) that can be then inserted into a plastic housing, or insulated with shrink wrap tubing.

– finally place the other end of the flex cable on the cellphone PCB so that its wires align with the pads where the LCD connector used to be placed before. Once it's aligned well, use tape to fix the cable in place.

Here is the result after the above step:

IMG_0416.JPG

Finally snap back the LCD to the board. Your flex-flat wire should be "sandwiched" between the LCD screen and the PCB.

The final result is on the picture (middle item):

IMG_0415.JPG

As you can see I've done couple of connectors to different screens that I pulled from different old Nokia phones.

The connectors are actually done using different methods. The first one (to the left) was from a Nokia 3310 phone, and I soldered the wires directly to its pins – not very elegant but it was my first try. The one in the middle I described above and for the one to the right I etched a custom PCB from a thin copper clad to replace the flex wire. Notice that  I  left one cellphone PCB intact, for the other 2 items the PCB was trimmed. The PCB  can be cut easily using a pair of heavy duty aviator snips.

Below is the connector that was done using a custom etched pcb,  (I created it since I couldn't find a flex wire for this one, the flex wire is still my favorite). As you can see the mounting principle is the same:

IMG_0419.JPG

 

Please note that all my connectors have 8 pins at the other end and are compatible with the Nokia 3310 screens (other similar screens are 3315, 3330, 3350, 3390, 3410, 5510). They have the  following pinout:   1. VDD / 2. SCLK / 3.SI / 4. D/C / 5. CS / 6.GND / 7. Vout / 8. Reset

The screens that have 9 pins are from later phone models 5165,5170,5180,5180iP and they have 1 extra pin (Osc) that I connected to VDD and thus got a 8 pin connector at the other end.

I noticed that the 9 pin screens require a slightly higher contrast value, but  other than that they are compatible with the 3310 series screens.

Although this tutorial does not go into detail how to program these screens, now that you know an easy way how to physically connect these screens,  you can find lots of information on the web, including ready libraries for the AVR and PIC microcontrollers.

 

///starlino///