Building a product from scratch part 3 (The Display(s))

Standard

For the screen, I wanted a challenge. I wanted to use multiple small one coloured OLED displays.  The displays I found online were from Aliexpress. And are inexpensive for what they offer.

LCD or OLED

The OLED displays are quite expensive compared to their LCD counterparts but they do look better. There is no screen back-light for OLED displays this makes them look pleasant for the eye. These OLED displays come in 2 colours. Blue and White.

 

Data protocol

These displays usually use I2C and SPI. SPI is faster but I2C is easier to implement if your microcontroller supports it. On the same hand, I2c uses only 2 wires for communication and SPI uses 5. This makes the PCB design way easier. Using I2C became challenging because the displays can only have 2 addresses and I2C does not allow 2 displays using the same I2c address on the same bus.

Display options

For the screen, I wanted a challenge. I wanted to use multiple small one coloured OLED displays.  The displays I found online were from Aliexpress. I started with smaller 4 0.91″ OLED I2C displays. I used for a while until I realized that they are just too small for the task. I quickly switched to the bigger 1.3″ I2C OLED displays that are really popular among hobbyists.

 

Resolution

The 0.91″ display is 128×32 pixels and the 1.3″ display is 128×64 pixels. It’s a no-brainer.

Connectors

These displays come with their own driver board to which the display ribbon FPC is soldered to. The FPC is 30pin and 0.7mm pitch.

But they come in another version that does not need me to solder the display which should help with the testing. At least that is what I thought. The FPC version is not to be found on Aliexpress but they are sold on buydisplay.com for twice the price.

This display cannot be used without a matching ZIF connector. The connector is 0.5mm pitch and is way harder to solder. I ended up not using these displays as soldering the 0.5mm pitch ZIF connectors was a nightmare. I ended up with a 30% success rate… at most.