Two wheel balancing robots are fun to watch. They are unusual to our eyes and always seems that it will fall. The secret is that those balances constantly struggle to fight the flipping by adjusting its vertical position. This is how famous Segways work – they constantly try to keep vertical. Simple enough, but when you try to build something similar, there are quite enough technical challenges. Madefrutos have built a lightweight balancing robot based on Arduino Nano, which packs some interesting features.

The robot so called VertiBOT was built with educational intent. The control algorithm uses kalman and complementary filter methods along with PID. Each wheel is driven by two small motors that are controlled by Atmeta328 in Arduino Nano. Robot determines its current position using 6 DOF accelerometer and gyro ADXL345/ ITG3200. Robot chassis has been 3D printed that makes it really unique. Since it is more educational project, you will find a nice description along with some theory that might help you to build your own balancer.

Swimming robots is an interesting area to give a try. If you have already built robots that walk, ride on a dry surface, then to fill the gap, you should make one that swims. Boris Landoni have made a pretty simple construction robot that mimics the fish in the tank. It’s construction is fairly easy – An Arduino with three servo motors controlling tail, fin and torso.

There are also couple sensors that are used to detect obstacles. The infrared sensor does the job pretty good. Fish propels itself by creating harmonic motion with all three servos. It looks pretty realistic and with proper skin on body you may be fooled.

The most annoying things when watching TV is loud commercials. It’s an effective way of brainwashing and there is nothing you can do about it. You can always turn volume down or hit another channel. Techbitar suggests using simple electronics to adjust TV sound on loud commercials.

His solution uses an Arduino, sound sensor and IR LED to get things in control. Arduino simply monitors sound level and when it reaches some threshold, it sends IR command to lower TV volume. Device has an IR receiver which allows to record commands from remote, so it can be used for many types of TV’s. Probably you wont be able to watch TV any louder than hard-coded threshold. So this may be a problem in some cases, but a little tweak could solve this problem too.

Tiny circuits have introduces really small Arduino board. It’s even smaller than a quarter coin. On a circle shaped PCB there is Atmega328P microcontroller in MLF package. On the edge you can find reset switch, status Led and battery connector. Due to size constraints USB connectivity and ISP is implemented in external tiny shield. These shields can be stacked one on another using special miniature connector.

Modular structure allows to achieve small sized applications that may fit in to small robots, rocket models or in any tight space. There are already several shields available – USB & ISP, 16 LED and bunch pr prototyping shields. They also come in 20mm square shape. Be sure to check out TinyLily as well.