Wemos D1 Mini Police Project

TOPICS:
Wemos Police ProjectThe Fuzz. The Po-Po. The Rozzers. The 5-0. What do you call the police?

10/03/2019

“HANDS UP!”…”GET ON THE GROUND NOW!”…”DON’T MOVE OR I’LL KICK YOUR ASS!”

Ah yes, classic lines from some of my favourite cop shows. The drama and excitement of policing is fun to watch from afar, but I don’t think I’ve got the plums to do that job myself.

For those of us hiding in the safety of our living rooms, there is a way to feel like you’re riding the ‘blues and twos’…albeit a bit of a nerdy way…

Let’s make a badass crime-busting police car project with the Wemos D1 Mini, some LEDs and buzzers!

Getting into Character

We can’t do this whilst we still feel like helpless civilians, so I refer you to my brother from another mother KRS-One to get you into street cop mode *whoop whoop*:

What We’re Making

This project hooks up two buzzers and LEDs, and with some simple code it’ll make sounds and lights just like a bank-robber-chasing meat wagon.

The buzzers make use of a nifty Arduino ‘tone’ command which makes it easy to pump different tones out of the buzzers.

Here’s a video showing my finished project in action (it’s noisy, careful now!):

What You’ll Need

This is a nice simple project, requiring readily available and affordable parts:

Wemos police project parts
A few simple everyday components are all you need

How to make it

Here’s a Fritzing diagram showing how I have my circuit hooked up:


Thanks to Fritzing.org for the fantastic software

Here’s my breadboard project to give you an idea of what that looks like in real life:

Wemos police project breadboard
I use two buzzers to pump out two tones at once, which creates the ear-splitting ‘nee naw‘ you hear flying past you.

So it’s simple enough – each of the LEDs has the negative leg going from GND through a resistor, and the positive leg runs to a GPIO pin. The buzzers are the same just without the resistors. Easy!

Some pointers:

  • Buzzers have a set polarity (+ and -). Any half-decent buzzer should have a longer positive leg just like an LED, and should also have a ‘+’ printed on the top.
  • LEDs also have a set polarity of course. The longer leg is the positive (+) leg. Get this wrong and you’ll kill your LED.
Buzzer legs
Like LEDs, buzzers usually have a longer leg for the positive terminal

How to Code it

If you haven’t yet set up your Wemos D1 Mini in the Arduino IDE – check out my post on that here.

We’re going to be turning the GPIO pins on/off to make our LEDs mimic a hot persuit in action.

We’re also using the Arduino ‘tone’ command to produce a different tone for each buzzer. This