7 segment countdown timer

Hi all,

I am trying to make a count down timer with a rotary dial and a 7 segment display. (A kitchen egg timer).

I was considering this product

but will I be able to control this from with-in node-red?


As it seems like there is no contrib node available for the HT16K33 you have to use the generic i2c node. With the help of the data sheet of the HT16K33 it should be doable.

But for an egg timer the 14segment is a little bit over the top. So perhaps look for a 7 segment board which are nicer to read and normally come with the two dots separate minutes and seconds (you get the for a few €)
Or one of the cheap lcd matrix boards - make sure you grab the i2c version.
Hope the raspberry pi has other things to do than a simple countdown :crazy_face:

Hey thanks. I actually have the 7-segment with the : separator in my drawer so I will try that.

Would I control that the same way?

Take a look at the chip the module uses and search if a custom node already existing for that. Look at the voltage for power (mostly named Vcc. Most of the modules uses 5v to drive the LEDs.
The logic level of the i2c bus is sometimes problematic as raspberry pis using 3.3v. Best is to do some research online if you need a level shifter.
Then use the i2c scan node to see if your module is detected on the bus. Perhaps you have to add pull up resisters for data and clock but oftentimes they are already installed on the boards.

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