Who are dealing with photography probably know what is Lux meter. Simply speaking Lux meter measures illumination what means light power falling on a surface area. There is whole physics about illumination and light energy. Simply speaking Lux  is well fit to light level from sense of human eye.

Lux meter uses a photo diode to sense light power. Diodes current is then converted to voltage which is calibrated by opamp. Then voltage is read by ATtiny26 ADC converter. And then Lux value is displayed on 7 segment LED display. Due to ADC range device is capable to measure up to 30000lux. Firmware is available for download.

Nokia 3310 graphical display seems to be very popular among embedded hobbyists. Probably because of it’s availability, lots of examples over the internet and simplicity of interfacing. Wichit Sirichote has developed simple scope application by using his project 8051SBC board.

Interfacing of display is very simple as it uses serial interface. The only thing you should take care when using 5V logic is to reduce LCD voltage to 3V level. This can be simply done by using two general purpose diodes connected in series. This provides approximately 1.4V drop. Source code is available for your experiments. Also you can see live action of this simple scope in this video. Of course this scope can’t assure you proper characteristics but this example gives you great info about interfacing 3310 LCD.

PCB developer may find this project very handy, because it has all features needed to control ultraviolet exposure box. Timer does what it has to do - it lights UV lamps ON while counter counts down time and switches lamps off when time reaches zero.

Timer also has a display of 4 seven segment LED indicators where exact time can be viewed. There is also a bicolor led used for indicating timer status (standby and count on). LED display is traced on separate PCB so it could be integrated in front of PCB exposure box. Source code is available in asm language (ready to flash hex as well).

This small AVR based APRS tracker is designed to be used in balloon. Tracker can be interfaced with GPS receiver; also it has several analog and digital I/O where various sensors can be attached. WhereAVR has ability to decode ax.25 packets, what allows reception of remote commands like real TNC does.

Board itself is built around ATmega8 microcontroller which has all necessary functions built in. Tracker is able to generate 1200-baud audio signal which is used to modulate carrier radio signal. I also have a zero-crossing audio signal detector. And of course what tracker would be without GPS module.

Module was put on a test where balloon flew above 90000ft. It worked fine … but its gone somewhere over Atlantic. Nice project to learn from. Author provides all necessary files in case you want to repeat his experiment.

These MIDI drums are really simple and so much cheaper than commercial devices, but they are fully compatible to midi interface and can store MIDI data in real time.

Midi Drum circuit is built around PIC16C84 microcontroller where all eight RB port pins serve as inputs. Each input is detected what leads to unidirectional and asynchronous transmitting of equivalent note through RA0 pin. Midi drum box also has four buttons to navigate through settings menu where you can change channels, memory configuration. Source files are also available.