Medical equipment is expensive and not always accessible to a wide audience. In fact, in any biomedical measuring instrument there is nothing extraordinary – here you can find ADC, analog front-end with low noise op-amp, some controller. But the central part what makes it different from consumer electronics is safety. Because device is connected to your body through some sort of electrodes, there is always a risk of electric shock. So power supply has to be isolated if it is powered from mains. There might be other additional safety circuitry to prevent possible hazard. And of course there are many safety regulations and certificates to overcome before device can be used with patients. This is where main cost comes from. It doesn’t mean that you cannot experiment with your body signals. You only need to know what are you doing. If you are building your circuit to acquire bio-signals, be sure to use a proper isolated power supply, even better – go with battery power. Once said, let’s look at great development of Arduino shield to be used for acquiring various bio-signals from your body.
Tired and bored of the same old business cards? Why don’t we make a different by changing it into a bizarre yet stylish “Business Board Card”? Well, anything is possible especially with the equipment of AVR microcontrollers. The ATmega168 is a popular AVR microcontroller that been used commercially in the Arduino board. This “Business Board Card” concept is a new breakthrough, which you can find all of the copper traces are located at the bottom side, which it can efficiently cut off the cost. The microcontroller will be placed on the top side, where is can be perfectly embedded in a standard DIP socket. You can see the input connections for power (typically 3-5 V) and ground in the upper left.