Interactive contact sharing isn’t new stuff around. Most of them use RFID tags or other wireless toys to share info between them. Other simple way is to store tour contact info in USB flash disk that starts up when plugged in. Or there is an old-fashioned way – use paper contact cart which probably is most reliable but less cool.

Here it is another great solution that can be easily made at home – an USB business card which actually looks like real card but with USB connector and a small Attiny85 chip on it. This card acts as a keyboard which types text on any word processing program once caps lock key is pressed few times. Design is very minimal – even USB connector is made on PCB itself. Microcontroller runs USB by using well known V-USB solution.

Why would you need a heart rate logger? Obviously for monitoring  your exercises and other physical activities. By analyzing hear rate graphs you can make decisions on whether to increase or decrease intensity.  Check it out and Arduino based heart rate logger that pick up pulse from heart rate transmitter T31. As it transmits a 1ms electromagnetic pulse every time a heart beat occurs there is a receiver RMCM01 for it that can be purchased from SparkFun. It operates without antenna and can be easily integrated in any embedded project.

Once pulses are captured then Arduino stores this information to SD with help of data logging shield. So not much of circuitry to be done except mounting receiver to this shield. Once finished load a sketch and start your activity. Logger creates new data file each time the arduino is reset. Upload these files to your desired PC software and analyze, graph and process it.

Plaing with Arduino or other microcontroller is quite fun. But probably most satisfaction is when you take more challenging tasks where several platforms are involved. Like in this project Arduino reads potentiometer/joystic data and sends it to computer Java program. As you can see form example code is pretty simple to get data from hardware to software – of course when you know what you are doing.

NetBeans based project has been written to read only one (x) axis data and move dark square along white screen. But having this code snippet there is an open waters to do anything you want including simple games or other manipulations. And this doesn‘t have to be Arduino – it just reads ADC and sends it via USART.

Microcontrollers usially come with intergated USART interface where all transmitting is done by hardware. All you need is to preconfigure parameters and push data without thinking of sampling it. Anyway there can be situations where you might need to do this in software or simply it would be interesting to study it. Then tak a look in this small tutorial like project where simple RS232 routines are run compleately in software by using old good PIC16F84 microcontroller.

To avoid bilndness there is also a LCD screen used where you can see the values sent via serial interface. Program is written compleately in asm code. So there is never too late to go back to basics.