30-07-2012, 12:49 PM
ZX-METAL
zx-metal_e.pdf (Size: 228.26 KB / Downloads: 15)
Proximity detector
The heart of this sensor module is the TDA0161 chip from ST microelectronics. The
monolithic integrated circuits are designed for any metallic body detection by detecting
the variations in the high frequency Eddy current losses. With an external tuned circuit
they act as oscillators. Output signal level is altered by an approaching metallic object.
Output signal is determined by supply current changes. Independent of supply
voltage, this current is high or low according to the presence or the absence of a close
metallic object.
Operation
the complete schematic diagram of ZX-METAL. L1 the searching coil
connected with C1 to generate the signal. IC1 TDA0161 is proximity detector. It detects
the Variation in high frequency Eddy current losses. If the metal object is near the searching
coil, the output current will flow more. On the other hand, the current will be decrease
when the object is far from the searching coil.
R1 is the current load. If there is more current flow, the voltage across will increase.
Transistor Q1 will be conducted. LED1 will then turn on. The logic output at K2 connector is
Low or 0V. If no metal is detected, Q1 will be turned off and LED1 turned off too. The logic
output is High or +5V.
Testing
Make sure the Searching coil must connect at terminal block of ZX-MTAL module.
After that connect the ZX-METAL with the main microcontroller such as i-BOX3.0, Stamp-BOX,SCi-
BOX, AX-11, MicroCamp, RBX-877 or RBX-51 with JST3AA-8 cable (bundled iwith module). The
supply voltage +5V from thre main controller board will apply to ZX-METAL. Bring the sensor
to find the mtal object. If it can detect, LED1 will on and logic output is LOW or “0”.