Picture of Laser Tripwire with 4 digit 7 seg Display for Counting People
Ok its not really Purple but the rest it accurate. The EYE is the LDR " Light Dependent Resistor" and it counts people.


       A laser beam is directed across a doorway. The LDR is on the receiving end of the laser on the other side of the doorway.
When a person goes through the doorway and breaks the beam the counter is incremented by a count of 1.
Scene it counts the person coming and going, that's 2 counts for 1 person i just divide by 2 at the end of the day, or at anytime to get the true count of people.
It is not fool proof, sometimes it double counts. But sometimes 2 people go out at the same time and only counts as one. So i figure it averages out.


    First and foremost this Instructable would not be without the help and coding expertise of  frollard .
He is amazingly quick and precise.
   There is a lot of knowledge here and they are willing to share that knowledge to help us learn.
Some of the people i have personally been involved with are:  iceng , He was the first one to follow my page. Him and steveastrouk were the first to help me through an electronics question. I was happily surprised when they both answered my questions clear to the very end of the discussion. Others include: maewert who has some 30 years of coding experience and it shows, ignoblegnomeGoodhartpfred2 Phil B. These are not in any particular order and if i have forgotten somebody i am sorry.

OK on with the build.

NabhanF11 months ago

oh are you there iam confused about this project components and method will yu please explain it to me

endragu1 year ago
hi..is it possible to using arduino uno without removing the microcontroler?
WWC (author)  endragu1 year ago
Yes. You would need to use the Arduino pinout instead on the ATmega pinout.
Strontium2 years ago
cool circuit , and is that an arduino clone i see in the image up there?
and nice work
WWC (author)  Strontium2 years ago
Thanks for the comment and yes that is a clone. It is an ACEduino, made here in the Philippines.
iceng2 years ago
I like the fact that your ible is reliably authentic for a laser  trip wire of reasonable distance in feet.

Many previous trip wire ibles have been short distances ie a few centimeters.

Nice work :-)

WWC (author)  iceng2 years ago

While it can be rewarding to build something "FUN" or for fun.

I typically like to build something that can have some use to it.

maewert2 years ago
Ouch! That looks like it hurt!
WWC (author)  maewert2 years ago
That it did!
I am using a hot air gun to heat the glue, so it takes more fooling around with than an actual hot glue gun.