DIY: Obstacle detector with Audible feedback (IR sensor + Headphone jack + 555 timer)

We were inspired by the buzzer that you find in mobile and laptop showrooms – the ones that produce this annoying high frequency tone if you fiddle a ‘little too much’ with the displayed product.


We use a 555 timer in its Astable mode to produce the frequency tone and couple it with a digital IR sensor module. We do this by connecting the output pin and the ground parallel to R2 in the figure.


And as a result when there are no objects in the vicinity, the system produces a high frequency tone, but when an object is introduced the sound dies out.  This is attributed to the change in resistance value.

Here is another variation of the same:

LiFi using IR sensor and headphone jack

In our previous post, we explored using the Solar panel + Led as a LiFi module. In this post, we shall be using IR sensors in order to transmit data (tones and square wave signals) wireless. The schematics of the setup are given below:


One can use this to send square wave of any frequency independently as well. This has been demonstrated in the video below

Video Demo:
Watch the video demo for a live demonstration of the working of this concept.

This is not limited to tones, one can use it to transmit raw music as well.