Bipolar stepper motor control with Arduino and an H-Bridge

It is a well known fact that Stepper motors are awesome! The only downside is that they can be a bit trickier to get going than servos and plain old DC motors. If you are interested in the inner mechanics and theory of stepper motors, check this excellent post on PCB heaven. If you happen to have one of the cheap little 28BYJ-48 steppers with 5 wires  and a little driver board with them, check this tutorial instead. Here, I will focus on how to get a bipolar stepper motor (typically 4 wires) working with Arduino and a H-Bridge IC like the L293D , or the drop in improved replacement - SN754410NE .(more…)

Stepper motor wiring tutorial

Occasionally you may come across an old stepper motor salvaged from a printer, or an ancient floppy drive. If you are lucky, there will be a part number on the motor and after some digging around, you will come up with a datasheet. Often though, you will have a motor with no markings whatsoever and four, or six colourful wires sticking out. First, you need to figure out how the wires are paired to form coils within the motor. Trial and error may work, but there is a better way! All it takes is a multimeter. (more…)

Replacing a damaged Arduino Uno voltage regulator

While testing a new circuit on a breadboard, my good old Arduino Uno suddenly released its "magic smoke" with a loud pop and stopped working. On a closer inspection, I saw that a small crater had appeared on the 5 volt voltage regulator. The next step was to figure out just how bad things were. I powered up the board via the 5v pin from a regulated power supply and...the Arduino came back to life! It looked like the voltage regulator was the only damaged component. According to the Arduino documentation, the Uno…continue reading →

Arduino Joystick Module Example

In one of my rather frequent eBay visits, I came across a nifty little joystick module, much similar to the analog thumb-stick on the PlayStation 2 controllers. The module is very easy to use with an Arduino uno and only costs a few dollars. Several different versions are available from eBay, Adafruit, Sparkfun and other vendors, but they essentially work the same. Overview The module has 5 pins: Vcc, Ground, X, Y, Key. Note that the labels on yours may be slightly different, depending on where you got the module from. The thumbstick is…continue reading →

Daisy – an Arduino autonomous obstacle avoidance robot

Daisy is an old "Discovery Kids" projection alarm clock turned into an autonomous obstacle avoiding bot. The brain is an Arduino Mini. Two small servos, modified for continuous rotation, are used for a differential drive and a combination of 3 infrared sensors (under the "skirt") and 1 HC-SR04 ultrasonic sensor (the "eyes") detect obstacles. I used the built in piezo buzzer for the alarm clock to play some basic tunes and sounds when power is turned on. reading →

555 Timer Monostable Multivibrator Circuit

This  is a side project from my endeavor to program an Arduino Uno wirelessly (over Bluetooth) using a cheap HC06 JY-MCU Blueetooth Module I got from eBay. In order to kick off the Arduino bootloader and upload a new sketch, you need to reset the Arduino at the right moment, and hold the reset pin "LOW" for the right duration, or else things can go bad. Eventually I found out a circuit that does exactly what I wanted and, as a bonus, has a cool name: a "monostable multivibrator". I feel smarter just typing that!…continue reading →

Crazy Watch – Exploring electronics fundamentals

“It is good to have an end to journey toward; but it is the journey that matters, in the end.” ― Ernest Hemingway A few days ago my son came back from school with something that he had build in a Tech-Ed class. You had to carry a copper ring across a maze made of wire without "waking up the monster". If you touch the wire, closing the circuit, the eyes (LEDs) would light up. I know it is pretty simple to make a LED shine, but what got me intrigued was that…continue reading →

Soldering tutorials, tips and tricks

Breadboards and hook-up wires are great for prototyping and testing out basic circuits. At some point though, you will want to create something more permanent and robust. Robots move around, bump into things, shake and vibrate and wires tend to disconnect way to easy. Soldering will help fix that! The best part is that even though it may look a bit intimidating, soldering is actually quite easy. All it takes is some practice and using the right tool for the job. Below is a collection of soldering videos and tutorials that helped me…continue reading →