A simple, yet capable, seismometer that teachers can use to instruct the fundamental principles of seismology can be constructed using a Basic Stamp and two Memsic 2125 accelerometers.Each accelerometer has two axes. One accelerometer for the X and Y-axes and one accelerometer for the Z-axis were used in the prototype. The Memsic accelerometers are capable of measuring up to +/- 2 gs with a resolution of about .001 g. Taking into consideration the 32-bit limitation of the Basic Stamp and the 2uS resolution for measuring pulse width, the combo can resolve to around .002 g.source

This Infrared Heart Pulse Monitor senses heart pulse by means of an infrared earlobe clip .Reverse engineered circuit diagram of heart pulse sensor circuit board out of a treadmill. Notice that the output is level shifted for use by CMOS logic running on 4.5V regulated down from the 6V battery. The CMOS logic also controlls the power to the analog circuitry and infrared LED. source

This signal generator uses a three channel DAC to generate Composite video signal (CVBS) and S video signal (Y/C separated) at the same time, left one channel is not used in NTSC format. It is assigned for one of the color components of Y/CB/CR video format. This feature was not planned some years ago, but it has been added when started to draw the schematic this year, because NTSC television system might be obsoleted in the near future. The two different video format, component video and NTSC video, work in exclusive.source

This Altimeter used for measurement during a rocket flight, this altimeter reads barometric data and stores it 10 times per second in an 8K EEPROM until apogee is detected (when pressure starts to rise again). Then a MOSFET output is activated to trigger a pyrotechnic ejection charge for a parachute. An optional second channel can be used for dual recovery (small drogue first and main parachute later for soft landing without too much drift).

• Processor: AT90S2323
• ADC: TLV1541 or TLV1544 (10 bit ADC 1 or 4 channels)
• Sensor(s): MPX5100 (barometric)
• Schematics
• Programming language: Assembler

source

The original circuit required a regulated negative supply from National Semiconductor Linear applications book. This required powering the circuit with two 9 volt batteries.The application note shows the use of LM394 super matched pair transistorssource