Category Archives: Uncategorized

Setting up Puppet on Ubuntu

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In this post, I will explain how I installed a Puppet server and a Puppet agent on Ubuntu hosts. I spent a fair amount of time trying to follow instructions from different other posts with little success. This is why I thought I would share what worked for me. Setting up the server Create Virtual Machine First, I created a… Read more »

Using a TCRT5000 sensor with your Arduino

You need to know if an object is close to another one but without using a contact switch? The TCRT5000 sensor is a great and cheap option for that! It essentially consists into 2 parts bundled together: an infrared emitter and a photo-transistor.   Drawing 1: No object close to sensor Drawing 2: An object is close to the sensor,… Read more »

Using a Real-Time Clock (RTC) – NXP PCF8563P – with an Arduino

In this post, I will explain what a Real-Time Clock (RTC) is about and how to use it in your circuits. I will be using the NXP PCF8563P chip for the examples. You can find the data sheet for that chip here. A RTC is used to keep track of date & time in your circuit and make it available… Read more »

Reducing your ATtiny85 power consumption

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In this post, we will look at different techniques to reduce your AVR micro-controller power consumption. This is especially useful if you are running your device from batteries since it will allow them to last longer. More specifically, we will look at the impact of changing the micro-controller speed (frequency) and also at the impact of using sleep modes so… Read more »

Police Car Strobe Lights using a 555 Timer and a 4017 Decade Counter

Introduction Today, we will solve the mystery behind police cars strobe lights! Seriously, I was looking at a way to simulate those lights using simple LEDs and without any rotating components. Here’s the result on a breadboard: Solution The solution to that problem was pretty simple. I used a 555 timer to trigger a 4017 decade counter. I used 4… Read more »

Adding pins to your Arduino using I2C and a PCF8574P chip

You are working on a project built around an Arduino and you realize you won’t have enough I/O pins to do everything? There are different ways of working around that limitation. One of them is to use an Inter-Integrated Circuit (I2C) bus and a PCF8574P chip. That chip will provide you with an additional 8 I/O pins at the cost… Read more »

IoT Object : ESP8266 + DHT-11 on

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There’s a lot of buzz around the Internet of Things (IoT) these days. This post explains how to create your own IoT object that will read your house air temperature and humidity and send that information to a web site called Once your data is on ThingSpeak, you’ll be able to visualize it to see how the your house… Read more »

Programming an ESP-8266 with FTDI Programmer

The ESP-8266 is one of my best findings of 2015. I wanted to experiment a bit with what’s called the Internet of Things (IoT). It obviously involved connecting my projects to the Internet, so I looked for a wifi module that I could use with one of my ATtiny microcontrollers to push data to the Internet. On eBay, I found… Read more »

Introducing the 4017 Decade Counter

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The 4017 decade counter is a chip typically used for 10 of its output pins. It turns them on, only one at the time, in a sequence from 0 to 9. The chip waits for an external signal to switch to the next pin. Pinout Power Pins: – Pin #16 (VCC): Connect to VCC – Pin #8 (GND): Connect to… Read more »

Using 555 Timer/Oscillator

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The NE555 timer is one of the most popular Integrated Circuit (IC) out there.  It is sold since 1971, so it’s not exactly a new IC but it still does his job very well!  Even today, over a billion units are produced every year! The 555 timer is an integrated circuit that can be used to produce different kinds of… Read more »