The module operates on the doppler basic principle and has the capacity to detect a relocating item in it’s proximity that makes it optimum for applications that call for movement sensing for instance doorways, gates and lights.

Doppler influence takes place when a sound or radio frequency is transmitted and hits a shifting object, the echo of it adjustments relative for the pace and way the thing.

Doppler outcome illustration in everyday life

At any time puzzled why does the seem of the ambulance, firetruck or perhaps a honking car or truck changes as it will come nearer and passes by?

A going item that is certainly transmitting or echoing a frequency will compress it inside the direction it truly is transferring and decompress it during the way it's transferring from. The level of modify during the wavelength is relative to the thing’s velocity.

When a honking or sirened motor vehicle is shifting in the direction of you, It'll be read as ‘expanding pitch’ and when it truly is relocating far from you, are going to be listened to as ‘decreasing pitch’.

In daily life, police velocity gun is really a gadget that mainly capabilities on doppler result to stamp speeds of going automobiles.

The device transmits a particular frequency within a continous waveform, the wave then bounces off the automobile and it is recieved back again. The transform inside the frequency is then calculated to discover the velocity of your vehicle.

Human ears and Mind operate in precisely the same way with soundwaves and we're subconciously employing day-to-day to hb100 radar percieve going objects all around us without having to glance.

Animals and birds use it to perception Threat if it is going toward them or away.

Doppler effect calculator

You can find formulae to estimate doppler influence whether it's sound or radio wave.

file = f₀(v + vr)/(v + vs)

file would be the observed frequency. Illustration is the audio you below from a relocating ambulance once the doppler effect.

fo is the initial frequency. Case in point is the actual seem frequency emitted from that ambulance before the doppler outcome

v is definitely the velocity in the wave. Example the sound wave travels at 343 m/s and radio or light-weight travels at 299,792,458 m/s.

vr is the velocity on the reciever. Example, If you're stationary listening to the seem then it is 0.

vs would be the velocity of the supply. Case in point, the ambulance travelling at 70km/h.

If you know the values then you can use this calculator to solve the doppler influence.

HB100 circuit

The module has a straightforward design with IF(Intermediate Frequency), Electrical power and Floor Pins

The oscillator generates the reference frequency 10.525 Ghz that goes two techniques, initially 1 for the transmitting antennas and another goes inside the mixer .

When the wave bounces off any item, it truly is recieved by The 2 receiver antennas and goes In the mixer where it receives subtracted with the reference frequency.

If the item it bounced off was stationary, then the worth immediately after subraction are going to be 0, Considering that the frequency sent is same the frequency recieved.

On the other hand, if the thing was transferring then the wave bouncing again will have a doppler influence and can be distinctive from the first transmission. The value In this instance might be in addition to 0.

This price is Please read on the ‘IF’ pin.

Here is the entrance aspect with the module. The round white disc could be the Dielectric Resonator Oscillator (DRO) which generates the reference frequency at ten.525 Ghz.

The other major elements Listed below are the mixer and the reduced pass filter.

This can be the again aspect of your module and the most important elements Allow me to share the PCB antennas. Two for transmission and also other two for recieving.

Amplifier for HB100

Due to the fact HB100 IF output electrical power is low and ought to be amplified so that you can be go through by Arduino or just plugging into a speaker to hear it.

Possibly you may produce a circuit for from scratch or just buy LM358 module which works flawlessly with it

The amplifiction acquire is 100 moments, if you employ two of those you can obtain it to become 10,000 moments, and 3 can get you 1 million times get.