A circuit to use 2 single cell li-po / li-on batteries in series and charge them in parallel

I was looking for an option to create a circuit with a switch, so I can use two single cell li-on Nokia cell phone batteries in series, but charge them in parallel through a USB charger. The idea is to be able to install the batteries in a small robot, where they will not be easily accessible to charge with my regular li-po battery charger. I have a couple of these simple but effective battery chargers lying around, but they can only charge a single cell. After some digging around, I found the…continue reading →

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 →

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 →

Arduino program / sketch upload speeds

I am working on circuit that will allow me to program my Arduino boards (I have an Arduino Uno and a couple of Arduino Pro Minis) over a wireless Bluetooth connection. I am planning to use my cheap and easy to find HC-06 Bluetooth module  for this. One of the first thing to figure out is the baud rate that the Arduino IDE uses, when uploading the sketches to the various Arduino boards. I need to make sure that my HC-06 Bluetooth module is configured to communicate at the same rate, so the avrdude stays happy. I…continue reading →

Free Arduino reference guide

Erik Verberne teaches Information and Communication Technology (ICT) in Netherlands and looked into the Arduino platform in an attempt to enhance his department's curriculum. He diligently documented his research and is now sharing it with the community. The result is an e-book of over 200 pages full of examples and tutorials, from Arduino and ATTiny programming tips, to working with LCD and LED displays, playing sounds, detecting obstacles, wireless communication via IR and Bluetooth and much more. See the official thread in the Arduino forum for the latest update and a copy of…continue reading →

Shift registers: add more digital I/O to your Arduino

Shift registers are useful chips that can add more outputs or inputs to your micro-controller. The 74HC595, for example, provides 8 additional digital outputs that can be controlled with only 3 Arduino pins. Additionally, you can “daisy-chain” multiple shift registers to multiply the number of outputs even further.Below is a great video by Kevin Darrah explaining how shift registers actually work. He took an interesting approach demonstrating the functionality of the shift register using manual input via push buttons, rather than a micro-controller. (more…)

Simple Android apps with App Inventor

App Inventor provides a fast and easy way to build simple apps for Android phones and tablets. It is targeted primarily at those of us with limited, or no experience in Android development. App Inventor has a fairly intuitive graphical interface, where you first visually design the application screen and then add the logic by dragging and dropping a series of colour-coded code “blocks” that snap together with a satisfying click, when connected correctly. (more…)

Free course: Artificial Intelligence for Robotics

A free, on demand course offered by Udacity. Definitely worth checking out... Course Summary: "Learn how to program all the major systems of a robotic car from the leader of Google and  Stanford's autonomous driving teams. This class will teach you basic methods in Artificial Intelligence, including: probabilistic inference, planning and search, localization, tracking and control, all with a focus on robotics. Extensive programming examples and assignments will apply these methods in the context of building self-driving cars." https://www.youtube.com/watch?v=bdCnb0EFAzk&feature=player_embeddedcontinue reading →