If you are planning to make AVR USB-ISP programming adapter you may want to consider this version which is compatible to USBasp hardware.

Major features adapter has:

• small hardware design;

• STK500v2 compatible;

• AVR910 Support (alternate Firmware or Atmega168) ;

• Single side usable;

• Has 10 pin,6 pin and connectors;

• 1 kHz - 3 MHz ISP frequency ;

• Target Status LED´s;

• Target can be supplied with 5V @ 100 mA max from the programmer;

• Automatic shutdown when current is to big;

• Automatic detection of highest ISP Speed if wished (only with Atmega168);

• ANSI and VT100 compatible Terminal mode to make Settings and view Target Information without Programmer Software

• USB/RS232 Converter(optional);

• Bootloader Support.

Files are available in Eagle CAD format, PDF for convenient view. Also you may find Target 3001 format and Sprint-Layout. Project itself is well documented and easy to follow. Hardware and firmware are constantly improved what makes this tool even more useful.

This is one nice frequency counter developed by Peter Cousen. This is really low cost frequency counter as it uses elements available world wide.

The frequency meter can measure frequencies with 1 Hz resolution when measured frequency is up to 100kHz. Other features include:

• Auto-ranging with floating decimal point.
• Up to 7 digits displayed.
• Auto-adjusting gate speed (0.1 sec to 1 sec).
• Simple, ease to assemble, and highly stable readout.
• Sensitivity approximately 100 mV RMS (100 Hz to 2 MHz), 800 mV RMS @ 50 MHz.
• Input overload protected.

Circuit and firmware are available for download. You may want to check out modified version which allows counting up to 80MHz.

If you need simple LPC213x ARM microcontroller series test board you should try the one Ulrich Radig has constructed.

Board itself is simple but it covers all I/O that allows to cover all microcontroller functionality. Project files are available for download in Eagle CAD format.

This is nice project made by Ibrahim Kamal. His aim was to create robot which navigates by using its position data log. The hardest thing was to record distance and turning angle because of these parameters depends how precise robot is manoeuvering from reference point.

Author provides really good theory analysis of dead reckoning process and how this was transferred to 89C52 microcontroller which counts encoder disc pulses for distance and controls steering motor which controls the angle of robot turning. Also all operation data is displayed on 2×16LCD module.

If you need really big 7 segment LED display, you may want to build 6” size display modules that can be cascade connected in row up to eight digits.

Each module is controlled by PIC16F876A microcontroller and LEDs are driven by ULN2803 Darlington array chip, because one port needs to light 14 bright LEDs what consumes higher currents than port can handle. Project files and CCS C compiler example program are available for download.