AUG21
The minimalist oscilloscope
This is actually more fun project than useful. It is a single channel triggered oscilloscope that is realised using PicAxe 08M microcontroller. This oscilloscope waits for a measured signal, takes 42 measurements of that signal, store it internally and display results on LCD screen. LCD is from a Nokia 5165 and the whole device can be built for $6. Source code is available for download so it can be tuned and further modified.
Source: Ken_S
AUG20
Garage parking sensor
Parking into a garage can be very difficult task for some drivers. Instead of an old trick with a tennis ball hanging off of the wall, a clever little device is built that allows driver to park his car just right.
The main component of this device is PING))) Parallax ultrasound sensor and Basic stamp (PIC) microcontroller. There are three LEDs on this "parking helper" that display current position of a car in a garage. Green LED marks parking zone, yellow LED warns driver to slow down and red LED marks the stop-zone. When red LED blinks that means that the driver is too close to the wall and should back up a little.
Source: Chris Savage
AUG13
AVR based video game platform
For all electronic gamers there is a new game platform for game development.
Platform is based on AVR microcontroller without any other external active components, and it's quite impressive. Color picture is generated on RGB monitor with simple D/A converter made out of 9 resistors. Along with hardware author has also developed a very powerful API that allows us to code our own games. Here we can see a Super Mario clone that runs on ATmega168 and it works pretty smoothly!
Source: Jaromir Dvorak
AUG5
Rotating LED display in color
As we didn't see enough of these rotating LED displays... Anyway, here is another one but very nicely built and in multiple colors.
Dual-color LEDs (red and green) are used to produce three colors: red, green and orange/yellow. LEDs are controlled with Atmega8 via 74HC595D shift registers and motor used for rotating the board is from an old fan. The most interesting thing about this project is the way the command data (message to be displayed) is sent to the microcontroller; author used a fiber-optic thread to transfer IR light from above and through the rotating shaft to the IR receptor on the board. All in all, an excellent project!
Source: Aki Korhonen
AUG4
Electronic Temperature-Controlled Relay
Today in embedded world it is pretty hard to find an analog DIY project, even though in this project "digitalisation" would be an overkill.
So here is a pretty simple device that works as a thermostat in temperature range of 0-100 degrees Celsius. LM35 is used as temperature sensor whose output voltage changes with temperature from 0V (0 degrees Celsius) to 1000mV (100 degrees Celsius). TL431 precision voltage reference is used to provide with precise reference voltage for comparator, that will be compared with voltage from temperature sensor.
Source: escol.com.my
AUG3
Dual USB oscilloscope with ATtiny45
Quality oscilloscopes cost some money but there are also good USB versions available on the market. Now how about a $5 USB version that you can build yourself?
Here is a dual input AD converter that connects to PCs USB port. Windows application plots analog values received from ATtiny45's 10-bit A/D converters. Application is written in Visual Studio 2005 C# and the source code is available for download on the project page. Microcontroller's firmware is written in C and is also available for download. Sampling frequency does not exceed 100 samples/second, so this device certainly doesn't have the performances of those that we can buy from stores but it sure can be helpful!
Source: Yves Lebrac aka Jacques L.
JUL31
RS232 to infrared interface
Transmission of weak infrared signals could now be possible even through the Internet with this little device. A custom client-server application could be made that simply sends serial data over any kind of link.
So, here is a device that transforms received infrared signals into RS232 serial data. It also transforms received RS232 and sends it through the infrared LED that is on the device. Two of these devices basically form an infrared repeater through the RS232 port based on Microchip's PIC12F683. It is possible to send raw data as well as remote control commands! Pretty sweet device.
Source: Andrew M. Bishop
JUL30
Lazy man's USB RFID reader
When we want to connect our RFID reader IC to PC it would be great if it could be powered by and connected to USB port. To avoid building our serial to usb converter we can simply purchase one from a local PC store. In that case we need UART-TTL voltage converter.
RFID reader modules that we can purchase usually work with TTL voltage levels and are powered from 5V. As the serial to usb converter module offers "real" UART port with UART voltages, we also need MAX232 to make it compatible with our 5V reader. This can be done a bit differently but it involves opening and hacking into a serial to usb converter. Read on to see how it can be done to save some money and get an extra IC!
