Go figure, you’re sitting around on a bench with your family on the warm summer’s night. You and your family are chatting and laughing around happily. It would be even better, if you can have some excellent homebrew beer with your loved ones, isn’t it?

Is it impossible for you to spend over thousands of dollars out from your wallet to buy a brand new refrigerator? If you did, then you should consider building a beer fridge here.

This fridge thermostat has many useful features, such as:

1. It has a very simple and small design (It can be installed in the fridge easily),
2. Its power efficiency is good and can save a lot of energy,
3. It fully equipped with adjustable temperature setting.

In order to power the thermostat, you can use a battery pack and a 7805 voltage regulator to supply a nice 5V to the rest of the system. For temperature controlled switching, a 10k NTC thermistor is needed in this project.

As you can see on the above figure that the thermistor has been mounted high off the stripboard. This is to minimize the effect of any ambient heat that is being generated by the AVR and transistor!

After you’ve done with the fridge thermostat, it’s about time to attach it in the fridge.

You have endless of spare times during weekend, and you don’t know what to do with the free times? Well, if you have deep interest with the analog meter, then analog meter clock project will keep you busy for the whole weekend or more!

This project is based on an Arduino board, where it can reuse an old 5vdc wall-wart for the power supply. PWM mode is being used on the AVR and it’s quite easy for most of the home hobbyists. Although it was a little bit of work to manage PWM at the assembly language level, but the dev environment for Arduino makes it easy to be used.

Honestly, the clock logic is a very straightforward thing, where it’s simply a bunch of nested “for” loops to count from 0-59; 0-59; 0-23 and all these values will be written to the appropriate PWM port.

Beside that, you’ll need to apply the calibrate mode. This mode is an interrupt that writes the appropriate max value to the meters (23:59:59) and with this mode, it allows you to adjust the pots easily. Don’t worry about the calibration interrupts in the environment, as it was as easy as the PWM did! You surely can handle it without any hassle!

When someone talking about the ATmega microcontroller, most of you here must be very interested on it, as it’s one of the most popular microcontrollers that have been widely used, especially in electrical and electronic field!

By the way, do you have any chances develop or create SI Prog before? Well, if you haven’t, then you may want to test it out by your own, coz today you’re about to create a simplification LancOs’s SI Prog aka the Intelligent Serial Port Programmer!

The whole project won’t cost you too much, as you can use either ATmega8 or ATmega 32 as the main component. Oh, if your AVRs reset pin in datasheet have a bar on the name of it (Reset or has a circle outside the pin of it), then this programmer is the most suitable for you here.

One more thing that you should take note when you’re dealing with this project! Always ensure that the emitter and base of the BC547 IC is working properly, for the purpose you can use your multimeter in diode mode and check it. If you have detected an approximately 0.7 Volt drop occur between base and emitter, then it will work fine here!

Have you ever think about by combining the two different things: Infrad-red link and AVR then transform them into a cool stuff? Well, if you haven’t tried it before, you have to test it out today!

To cut the long story short, you just going straight to the point…

Firstly, you might want to build the prototype in stages. The first stage will contain just the AVR and an infrared detector with some bypass capacitors. Don’t waste your time build the circuit on breadboard, as it wouldn’t work. The breadboard is picking up noise, thus you need to remove the components from the breadboard and solder them to a prototyping board. Now, the circuit will be working.

Then, you would need to add a 14.7456 MHz crystal and the two capacitors on the prototype, which this for a more stable oscillator and more robust communication.

If you refer to the figure above, you see a complete device. On the left hand side, you will use a 2-pin power connector to power the circuit from an AC adapter rather than the NXT. The white 6-pin connector on the bottom connects the circuit to an AVR programmer and the gray connector, which next to it is connects the device to the NXT. The serial port is connected with the 6 header pins on the top right.

It seems that Arduino board has strong positions among electronic hobbyists. This makes a good base for various projects that can be prototyped very fast.

LED cube is made of 3×3x3=27 LEDs that is not much, but it is still FUN to play with. Full source code is available for compiling and modifying it.