All posts on February, 2008
Posted on 26 Feb 2008
Having the doorbell ring just when you fell asleep, after your all-night soldering frenzy, can be a real annoyance. This simple project use An ATtiny12 microcontroller as a timer and some switching circuitry turns the doorbell off for 10 hours at the same time each day[more]
Posted on 26 Feb 2008
This is good looking and practical device that may be useful in many areas where count down timer is needed (no bombs please). Its time can be adjusted in range from 1 minute to 99 minutes. It displays time sequence on BCD decoded 7 segment LED display. When count down finishes - timer sends a control signal to relay.Complete design is made on wiring technique, so no PCB is available. Project is very well described with circuit operation animations what is really helpful for circuit beginners. Source code is also documented well with flow charts. Assembly code and hex file may be downloaded here. [via][more]
Posted on 26 Feb 2008
This is a single transistor FM transmitter that is about the size of a standard AA battery. The site has all the schematics and technical specifications needed to complete the project. Let the bugging begin! .Main advantage of this circuit is that power supply is a 1.5Volts cell (any size) which makes it possible to fix PCB and the battery into very tight places. Transmitter even runs with standard NiCd rechargeable cells, for example a 750mAh AA size battery runs it about 500 hours (while it drags 1.4mA at 1.24V) which equals to 20 days. This way circuit especially valuable in amateur spy operations [more]
Posted on 26 Feb 2008
This project is for detecting human ECG (Electrocardiogram, or EKG). A tiny amplifier is embedded (<1mA). The on-chip Timer, ADC and DMA (double buffering) are used for getting ECG data. An IIR filter and hardware LCD scrolling are used for ECG rendering. User can simply touch the Primer by 2 hands, his/her ECG trace is scrolling alive on the LCD screen. The instant heart rate is displayed with beep sound and LED flashing. The device also delivers and displays the ECG on a PC through the USB cable.[more]
Posted on 24 Feb 2008
This Laser range finder is a very cool project.You can build one with a web cam, cheap laser pointer and a bit of C++ programming and VideoOCX ActiveX component installed on your computer. The complete build, along with all the source code, is available on the site.There are many off the shelf range finding components available including ultrasonic, infrared, and even laser rangefinders. All of these devices work well, but in the field of aerial robotics, weight is a primary concern.
It is desirable to get as much functionality out of each component that is added to an airframe. This page describes how a mini laser pointer can be configured along with a single camera to provide mono-machine vision with range information.[more]
