|
|
Introduction
The circuit is
drawn for measurement of acceleration from
–1000 mg until + 1000 mg. It can be placed in kantra'n the car and be
supplied from the sheath of electric lighter. The circuit includes one
indicative LED and a screen LCD.
The shematic diagram of the circuit. |
The connections for ADXL202. |
Description
The measurement of
acceleration becomes with the use of IC from Analog Devices, the ADXL202. The particular
element contains 2 autonomous vertical between them sensors, for the
measurement in two axes. For the particular application becomes use of only it's
one. Acceleration meter measures dynamic or static acceleration from –2g until 2g (where g is the acceleration of
gravity) and when this is equal to zero, exit is a signal PWM, with
Duty Cycle 50%. As long as the acceleration increases, increases also the Duty
Cycle, with biggest response the 75% (in the 2g), while for acceleration –2g, the Duty Cycle is 25%. As conclusion
from more, has that for change 1g, is altered also the Duty Cycle of exit at 12,5%.
With the shooting
of switch of starter, the circuit is supplied. In the beginning, and as long as
LED is power-off, becomes initializing of meter. Acceleration meter is will be
always placed so as to it measures the acceleration at the address of movement
of vehicle. As long as however well and it is placed this, will always exist a
component vertical in the movement and with time to the centre of ground. This
component is the acceleration of gravity and which is always removed from each
measurement. As soon as the LED turns on (in minimal time), then the initializing
it has become. From now on the meter measures the acceleration and him presents
in the screen. When is presented the symbol "-", it means that it is
deceleration.
Designed by:
Published at 06.10.2004 by Serasidis Vasilis Http://www.serasidis.gr