Optical sensor TCST1000

Hi, I'm new in Arduino... So... I would like to connect an Optical Sensor TCST1000 ( Link : http://www.alldatasheet.com/datasheet-pdf/pdf/26408/VISAY/TCST1000.html ) to Arduino, and each time that i cut the light in the sensor, i would like to have an output of 5v on a digital Output.... I've look everywhere but nothing on the web that can help me...

So, someone can help me to know how i've to connect the TCST1000 ? and how can i use his analogic input ??



I suggest this circuit:

Thanks for your answer, now i've to know how can i read the value....



Just use the digitalRead() function.

Ok, i'll try .... and i'll say you...



Hi, I'll try your circuit and it dosen't work, I'see on the web that the photointerrupter need 12v... Is it true ? Or with 5v its ok ?




No, it doesn't need 12V.

You should measure the voltages at the relevant nodes (collector of phototransistor, voltage across LED resistor, etc.) in an interrupted and non-interrupted condition and see if they make sense. First, make sure the voltage across the LED resistor is about 15-20mA. If not, the LED is not giving off any light.

With no interruption, the voltage at the digital input pin should be no more than 0.4V. If it is higher, then there is a problem. With an interruption, the voltage at the digital input pin should rise up to nearly 5V.

Measure these values and let us know what you find.

First, make sure the voltage across the LED resistor is about 15-20mA. If not, the LED is not giving off any light.

Also, if you've got a digital camera or camera phone, you may be able to see the light from the LED in the electronic (not optical!) viewfinder. Try this first with an IR remote control.

Hi, thanks for your time... i don't understand... if you have an e-mail, i can send you a photo of the circuit... so you can see if i do something wrong...



Just post the photo here, paste the URL of it in between the bracket comments that come up when you click the picture icon (third from the left in the top of the reply box).

make sure the voltage across the LED resistor is about 15-20mA.

What that means is that with 15 mA flowing through a 220R resistor you should measure about 3.3V with your volt meter across the resistor.

The circuit will work if you wire it up correctly.

Ok, this is the photo.... En reality i don't found a tcst1000 here in colombia... but a Japanese one...

SO maybe i've to buy something more professional...


Thanks and look the photo


KinoLab arduino.jpg

Sorry... here is the photo...



Hi, i don't know if someone can help me....

I've tested and : The general circuit of arduino give me : 5V and 14mA So, if i connect a 220R to the led he give me 8mA...

And in the other side, if i connect a 22kR it give me 0.01mA and in the output for the digital PIN there are always 5v....

Anyone has an idea ?

Thanks and regards....


Sounds a similar device to what I use on a project although its a reflective sensor. I hooked it up to an analogue input with a threshold value and used a 330K resistor on the photo transistor side. I couldn't get a clean enough switchover to use a digital input. Just try changing the resistor value and measuring the output voltage with a voltmeter whilst interrupting the beam. You'll generally get a bigger voltage change by increasing the value of the resistor on the photo transistor. I'd leave the resister on the led as is. I only have 5 milliamp running through mine and increasing it had little effect on the sensitivity of the device.

Loook.... now everything it's ok.... IT DOES WORK.....

It was a problem of wiring........

Now my second problem is : I would like that each x cut of the sensor it give me an 5v output.... How can i write in the programm ???