Electro Sparrow

Hello!

For our next project, we’ll be using an ATMega328p and two 7 segment displays to implement a decimal counter. This can be useful if we want to implement a project that gives visual feedback to the user, like a thermometer (our next project).

To implement this, we’re going to rely on the POV phenomenon (Persistence Of Vision) to decrease the number of pins used by the displays to 9: 7 to the “bus”, that tells both displays what segments to lit, and 1 to each display common, to select which one displays each number.

Hardware list:

1 – AC/DC Adapter or some kind of DC PSU (not pictured)
2 – Breadboard
3 – L7805CV (bottom left) – Optional
4 – 150 ohm resistor for the power led – Optional
5 – The trusty ATMega328p – You can use an ATTiny2313A with few source changes.
6 – 28 pin socket (bottom right)
7 – 7*100 ohm resistor for each display segment – Optional, but recommended
8 – 2*Common Cathode Hex display – Again, you can use common anode with just a few source changes.

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