Microcontrollers have a limited number of I/O pins. And sometimes you need more than you can get. But there is always a solution. For instance is this simple project Arduino board controls a LCD via 3 wires.

Technique isn’t new. I bet many projects are already using this technique. Solution is simple - arduino sends serial data to shift register that sends it to LCD via parallel lines. Of course when doing such modifications - standard LCD control libraries won’t be useful any more. For this particular case use this one.

While looking for better performance than 8 bit microcontrollers Wichit Sirichote have constructed 32bit single board computer on old 68HC000 chip. He spend couple of months to finish his project and made quite powerful kit that is capable to run embedded linux.

Computer board features 68HC000 32 bit microcontroller running at 8 MHz speed, 256kB of FLASH memory and 256kB of SRAM. Other features include:

• GPIO: 8-bit output port, 8-bit input port,

• UART: 6850 9600 8n1,

• RTC: DS12887,

• Glue logic: DTACK, memory/io decoder, Xilink XC9572 CPLD,

• Monitor program: zBug V1.0 for 68000-Based Single Board Computer.

There is also CPLD Xilinx 9572 used in board computer for decoding memory and generating necessary logic signals. Author intended to use this board to run GCC compiler. If you want to give a try – all files are available for download, but keep in mind that it is not easy project for beginners.

This device was developed by Velimir have been used for monitoring 16 digital values in the car including fuel level, temperature, door closing. All signal inputs are optically isolated.

Car monitor displays events in LCD display and has sound alert ability. Project is based on 68HC11 microcontroller running at 8MHz frequency. Schematic, PCB and Source are also included.

Device was developed to measure distance when riding bicycle. Magnet and magnet sensor (proximity effect) contact was used to sense wheel turn. Project consists of Motorola 68HC908QY4 microcontroller which counts pulse signals coming from reed switch. Data is displayed in 1X16 LCD module.

Schematic is very simple and can be rebuilt easily on universal board. Software is written for ICC08 compiler and can be modified easily. Main modification would be adjusting wheel diameter.