Hook me up.

Here’s what I started with.

I've got to wire the thing on the left to the thing on the right

I started by wiring up the positive and negative to some rails

Then I wired the temperature sensor to analog pin 5, ground and 5V

A piezo wired to digital pin 9 for PWM and 5V.

The last of the sensors. The tilt switch is wired to analog pin 0 and 5V.

How to wire up a number display

Now for the fun stuff. To wire up the number display and the transistors that determine which digits are showing I used this diagram that I made ages ago.

Here’s basically all I need to know.

There are 16 pins on the number display. The ones below need to be wired to the C leg of transistors. In this case I just used good old BC547s.

Pin 1 is gnd no1

Pin 4 is gnd no 2

pin 5 is gnd no 3

pin 14 is gnd no 4

When I say ground I mean that when these pins are connected to ground the digit that they correspond to (i.e. pin 4 turns on the second digit) turns on. By using transistors we can control this and have numbers and other stuff display on the digits.

So for example if we want to control when we want the first digit to light up we do it like this.

B to number display pin 1

C to analog pin 1

E to ground

When we switch on analog pin 1 in our program our first number lights up. Simple.

(oh yeah and if this way of wiring these displays isn’t right then sorry but I just figured out this way from experimenting.

The transistors all wired up mad scientist style.

The finished product

So that's pretty much all the circuitry I need to do for this project.

I know it looks messy and I could have just used a number shield or shift registers but I like it like this. It kind of adds a mad scientist look to my room and makes me look a bit like this guy:

Flint from cloudy with a chance of meatballs

Flint from “Cloudy with a Chance of Meatballs”. Credit to the guys who made the movie.

Next up, debugging the circuit using serial.


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