The post explains how to transform your ordinary trousers into a chasing LED lit trousers which produces an shooting LED light chasing effect in response to your footstep movement or thumping.
The Circuit Concept
The proposed foot step activated chasing LED trouser will enable you to decorate any piece of clothing with LEDs that will respond to your walking pattern or your footstep vibrations.
As long as you are motionless or not walking the LEDs will stay switched off, and as soon a foot step is detected, the LEDs will jump in a chasing or sequencing fashion to create a dazzling and fluctuating bar graph like effect.
The above feature is actually helpful in keeping the current consumption to the minimum so that the attached battery can last for a much longer duration of time compared to the other forms of LED trousers where the LEDs are always ON wasting precious battery power.
Moreover the idea generates an eye-catching running light effect with every step you take.
Simulation and Working
The circuit is actually a simple vibration sensor which relies on the vibrations picked up by an attached mic.
The sensing circuit is configured around the IC LM3915 which is a dot/bar LED driver chip, it's primary function is to convert minute voltage variations into correspondingly fluctuating output in the form of sequencing LED graph.
In the shown LED trouser chasing light circuit, when a vibration is detected (foot steps), the mic detects it and converts it into minute electrical pulses.
Precisely with every vibration impulse the mic momentarily produces short across it terminals, this results in momentary grounding of the base of the NPN transistor through the 0.1uF capacitor.
This in turn causes the base drive via the 1M resistor to become zero switching of the transistor momentarily.
This results in a full supply potential being allowed to pin#5 of the IC.
As per the specifications of the IC this causes the output of the IC to shoot and illuminate all the LEDs from LED#1 to LED#10 in a rapid sequencing pattern.
As soon as the foot step is paused the transistor is again switched ON shutting off all the LEDs in a blink.
The above action keeps on repeating as long the individual keeps walking creating a random shooting LED bar effect on the trousers.
The LEDs used should be high bright type preferably in blue/white/red colors or as per individual preferences.
The entire circuit could be powered by a single 9V PP3 battery, which should last for a long time unless you are running around non-sop with the LED trousers on, all night long.
Two such modules can be installed on the side stitch of the trouser legs, the mics should be place at the bottom of the trouser, preferably tied up with the heel side of the shoe, this should be done by terminating the mic through a few inches of flexible wires.
The shown 10k preset is for adjusting the sensitivity of the circuit so that the LEDs don't respond to external sounds such as loud music, vehicle horns etc.