Module main technical parameters:
1.Working Voltage : 5V(DC)
2.Static current: Less than 2mA.
3.Output signal: Electric frequency signal, high level 5V, low level 0V.
4.Sensor angle: Not more than 15 degrees.
5.Detection distance: 2cm-450cm.
6.High precision: Up to 0.3cm
7.Input trigger signal: 10us TTL impulse
8.Echo signal : output TTL PWL signal
Mode of connection:
Ultrasonic car video
The car using HC - SR04
HC-SR04 ultrasonic module can
offer non-contact distance sensing function, the
range of which is 2cm¡ª400cm., and the range
accuracy is up to 2mm; the module includes
ultrasonic transmitter, receiver and control
The basic operation principle is
use IO port TRIG to trigger
ranging. It needs 10 us high level signal at least
Module can send 8 pro 40 kz
square wave automatically, and will test if there is
any signal returned.
If there is signal returned,
output one high level signal via IO port ECHO. The
duration of the high level signal is the time from
transmitter to receiving with the ultrasonic.
Testing distance =duration of
high level*sound velocity(340m/s) / 2
Refer to the wiring diagram
VCC supply 5V, and GND is ground
wire. TRIG is trigger control signal input, ECHO is
echo signal output.
Picture 1: Physical map
HC-SR04 ultrasonic module
Output echo signal
Output TTL level signal, proportional to the
4. Ultrasonic sequence diagram
Sending signal inside the module
Output echo signal
Picture 2: Ultrasonic sequence
The sequence diagram above
indicates that you just need to supply one 10 uS
pulse or above to trigger the signal, inside the
module, it will send 8 pro 40kHz round electric
level with testing the returning wave. Once tested
that there is returning wave signal, then it will
output echo signal. The pulse width of the echo
signal is in direct proportion to the testing
distance. Therefore, the distance can be caculated
according the duration from the sending signal to
Here is the formula below:
uS/ 58=cm or uS/148=inch;
distance=high level time*sound velocity(340m/s) / 2
Suggestion: the measurement
period is 60ms or above, which can protecting echo
signal from sending signal.
(1). for this module, keep in
mind not to connect with electricity. If it is
connected with electricity, you need to connect up
the GND port of the module firstly, otherwise it
will affect the normal working of the module.
(2). When testing, the coverage
of the tested object is 0.5 square meter or below,
and try to make the plate smoothly., otherwise, it
will affect the result of the testing.
5. Specification of the object.