B2Ben have put a nice post about Charlieplexing lots of LEDs with only few microcontroller pins. In this demonstration he have chosen 20 LEDs that are connected to Attiny85 microcotnroller with 5 wires.

After his initial tests on breadboard he came up with nice PCB project that can be used as stand alone toy that plays patterns or runs Game of Life. Read more »

Inductance meter isn’t popular feature in multimeters as capacitance measuring. But occasionally we may need to find out unknown inductor value. Of course we could use oscilloscope and signal generator to evaluate it but this isn’t convenient way.

For this purpose Moser have constructed a L measurement circuit based on LC resonant circuit. Measuring resonant frequency and knowing C value it is easy to calculate L value. Project is capable to measure inductances from 80uH up to 30000uH. This sounds quite enough for hobby needs especially when it require very minimal circuit and Arduino board.

Most multimeters today have an auto turn off feature built in. But Florin from yourtronics found out that his cheap multimeter lack this functionality. This lead to multiple drained batteries because he simply forgot to turn off meter.

There is enough space in multimeter enclosure so why not to put a simple circuit that would take care of this. He put an Attiny25 based circuit that disconnects power after some time. Nothing really fancy but helps a lot.

G-Force is important parameter when measuring accelerations. For instance in cars, planes or other places where acceleration is present. Igor has decided to build a fully functional G-Force meter that reads accelerometer data and sends it to custom computer software via serial channel.

He uses a three axes ADXL330 accelerometer from Analog Devices. It is capable to measure G’s from -3G to +3G – so this is suitable for automotive testing. Readings are done with PIC 16F877 microcontroller that simply transfers data to PC program that analyzes it and plots in to convenient graph. If you’ll look closer you’ll find that there are more handy options that may be handy when processing, exporting data.