In this project I will show how I made an automatic visitor counter, It uses a 2 lasers to count how many people enter the building but will not count them again when they leave.
The circuit can count up to 99 with 2 displays if you wanted to extended the amount of visitors it can count just repeat the part of the schematic with another CD4026 and 7 segment and connect it in the same way as the other display driver. Just connect OUT (pin 5) of one of the display drivers and connect it to CLOCK(pin 1) of the next display driver.
The digits only count up when you walk into the building to do this I used a 555 timer to hold the signal for laser 1 on for 3 seconds after a person has walked tough it and when the person walks though laser 2 the digits count up as both the laser 1 and laser 2 have to be triggered at the same time for the circuit to count up. I have chosen to do it this was as if a person was to walk out of the building it will not count them again on there way out. You will need to change the resistor and capacitor to get the desired time for the delay. The delay will be dependent on the distance you have placed your lasers apart. I used a 330 ohm resistor and a 10uF capacitor that gave me a timing of 3.6 seconds.
If you do not want to use a PCB you could also use a piece of perfboard and use wire to join all the parts together. Use the schematic to help you with the wiring. If you have chosen to use a PCB then use the silk screen and schematic to help you place the parts then solder them into place.
I will be 3d printing an enclosure and I will be printing it soon. After I have printed the enclosure and checked to make sure it is suitable I will share my STL files.
Once your circuit is built you will want to power it. I would suggest using a 5v power supply but if you are placing it where there is no power you could use a battery bank but I'm not sure how long it will last for.
mount the counter unit to one side of the entrance at a suitable height and out of direct sunlight as this may affect the reading because the design uses LDRs. Then place the laser unit on the other side of the entrance at the same height and aim the laser onto the centres of the LDRs on the counter unit. After the units are mounted all you need to do is power the units and your done.
If you want to reset the counter just disconnect power and the unit will start back at 0 when the power is restored.
I designed, built and documented this project for my GCSE electronics coursework. My teacher marked the work and it achived a grade 9 (A* Old grade) I have included the project report, just click the image to the right.