Andreas Schwarz have built an AVR DDS generator which can generate Sine, Rectangle, saw signals from 0.5Hz to 25kHz. Frequency can be changed in 0.5Hz steps. Signal generator also has amplitude(0-10V) regulation feature with offset(-6V to +6V) adjustments. Whole control program is written in asm language, what makes it compact and optimal. Continue reading
Dheera Venkatraman have decided that using keys is boring and obsolete. So he managed to build electronic door unlocker. He used PIC16F630 microcontroller attached to PS/2 keyboard and stepper motor to slide the head. Keyboard is placed outside the door. When 5 correct numbers are pressed – the door unlocks itself. Circuit and C program is available if you want to modernize your college dorm room. Continue reading
Signal generator is must have tool on your working table. Buying one may be too expensive especially if you are hobbyist. So why not to build one. There are many generator chips available. One of them is Analog Devices AD9835 Direct Digital Synthesis (DDS) generator chip which is capable to generate sine wave up to 50MHz. This signal generator is programmed to output frequencies from 1Hz up to 10Mhz with 1 Hz step resolution. Generator is controlled with three pushbuttons while information is displayed on one sliding window LED display. DDS generator is controlled via PIC16F628 microcontroller. Continue reading
Seems to be that oscilloscope can be used not for displaying signals only, but it also can also used as generic display. So there was Oscilloscope clock born. Of course it would be ridiculous to put this scope-clock on you working desktop to show time, but it may serve as nice demo. From technical side this is fully functional clock running on AVR board. Signals are taken by using two 10x probes. Clock refresh rate can reach up to 250Hz. Firmware is written so that it prevents screen from burning-in(screen is automatically repositioned). Board itself has many features including battery backup, RS232 connectivity. It may also be interfaced with external GPS receiver. All files (including design and firmware) are available for download, but why not to buy tested and professional looking kit for only 25$. Continue reading
If you need simple LPC210x prototyping system, this project is right for you. Despite board simplicity it has all peripheral connectivity covered including RS232 interface for easy bootloading flash memory, JTAG and other if needed. There is plenty of space on board for other circuitry, that can be wired directly on prototyping area. So it may serve as learning tool or for complete project. Author provides PCB files so that everyone could build it by himself. Continue reading
Bob Blick have built this propeller clock some time ago, but it still serves as an example for other modifications. A motor spins the “propeller”, and a PIC16F84 microcontroller keeps track of time and changes the pattern on seven LEDs with exact timing to simulate a 7 by 30 array of LEDs. Moving led array makes illusion of flat image. Author provided all necessary material including circuit, PCB, and source code that may help to build it for everyone. Continue reading
