“Persistence of vision refers to the optical illusion that occurs when visual perception of an object does not cease for some time after the rays of light proceeding from it have ceased to enter the eye. The illusion has also been described as “retinal persistence”, “persistence of impressions”, simply “persistence” and other variations.“Wikipedia
So I wanted to make something for my sister on her birthday, so I thought it might be cool to make a 5 LEDs Persistence of Vision display printing “HAPPY BIRTHDAY” message.
It is one of the most well-documented builds on the internet, so I’m not going to do it again. Instead, I will share some details, few photos, and the code for the project.
I decided to use red LEDs with the current limiting resistors. To control the LEDs, I used a small PIC12F683 8-bit microcontroller. Two coin cell batteries powered the whole thing. As this was an easy build, I didn’t bother to draw a schematic for it. But if you refer to any other designs on the internet, it is the same.
It’s impressive that PIC12F83 has such a wide voltage range, the only limitation in terms of voltage was the (Forward Voltage of LED + 0.3V). I used the microcontroller’s internal RC clock for the build.
Here are few pictures of the final result. Later on, I poured in a lot of hot glue to cover the back.
Here, I used Long Exposure Camera App to take this shot. I don’t think this camera app really takes long exposure shots but instead uses image processing to get the same effect. Anyway, they turned out very well.
As usual, find the code on my GitHub page and happy building.