# 3 digit – digital object counter DIY kit

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Two digit – Digital object counter DIY kit is one of the most popular kits designed by BuildCircuit. The kit is very popular among electronics beginners and intermediate circuit players.

We are now releasing the upgraded version of the kit, a three digit digital object counter DIY kit.

The DIY digital object counter works with TSOP4838 infrared receiver  and there are three seven segment displays displaying numbers from 0 to 999.   An IR transmitter is oriented towards the TSOP4838 infrared receiver of counter module and objects are moved between the counter and transmitter modules. Each time an object passes between the two modules, the seven segment displays show increment in numbers.

The counter module can be reset to 000 at any time and restart the counting.

Watch the video below:

The counter can be reset to 000 by pressing the reset switch. The counter does not count if the IR rays are continuously falling on the Infrared sensor(TSOP4838). As soon as an object obstructs the IR signal, the counter immediately counts the interruption.

The maximum distance between the counter module and the IR transmitter should be around 1 meter.

The module can also be tested with general remote control. Thus, you can also call it as a simple remote tester. For each press on your remote control, there is increment in number. However, we cannot guarantee that it works with ALL the TV/DVD/VCD remote controls.

Power supply: The counter works with a 9V battery and the IR transmitter works from 6V to 9V.

Schematic of counter module:

Schematic of IR transmitter module:

IR transmitter is based on astable mode of 555 timer. The 555 timer, resistors and capacitor on the transmitter module output IR rays at 37.974Khz(approximately 38Khz). The TSOP4838 infrared module operates at 38KHz infrared frequency, however, that is not so strict with these kinds of basic experiments. It actually operates at frequencies between 30Khz to 40Khz.

Use astable mode frequency calculator for finding out the frequency of 555 timer. While using the online calculator, enter R1=18K, R2=10K and C1= 0.001uF, you will get 37.974 KHz.

## How to use the kit

Place the two kits facing each other in a straight line. The IR receiver TSOP4838 (on the counter module) and the IR LED(on the transmitter module) should be kept in a line of sight(straight line). When you move an object in between the two kits, the counter module counts the number of interruptions in the line of sight.

Watch the video below to know how to use the kits

Other related tutorials:

You can buy the kit at www.buildcircuit.com.au