E18-8MNK IR sensor connecting to Arduino

Other Hardware Sensors
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Hi all, my second post to the forum and I think it will be a relatively simple question to answer. It has been 20 years since I studied electronics, so I'm having to re-learn. I am building a race timer that is started by a motorized car crossing an IR beam and dropping the signal to the arduino to start the timer. My transmitter will be powered by a 9v battery in the center of a 4 x 8 board, and the receiver will be mounted on the edge of the wood attached to my USB powered arduino. I have the timer coded already and am activating it by a switch on my shield currently.

This is my problem. I have an Arduino Uno with a SainSmart 1602 LCD board connected to it. Here is a link:
http://www.sainsmart.com/sainsmart-1602-lcd-keypad-shield-for-arduino-duemilanove-uno-mega2560-mega1280.html

The board actually is slightly different from the image in their picture, because there are 5 rows on the bottom right of the shield with (5v, GND, S). These are near the A0-A6 inputs, so I am assuming they are inputs for analog sensors, I know what 5v and GND are, but what is S?

I purchased two IR sensors (E18-8MNK) from ebay that originated from "FunRobo" in HongKong. They are described here, but poorly. http://forum.funrobo.com/viewtopic.php?f=40&t=2375. They also appear to have their own shield which also appears to have Digital pins which also have (5v, GND, S), or maybe I'm confused?

I have built a 5v DC supply for the transmitter like they depict in the forum, however, I'm not sure where to connect the receiver side of the sensor to on my LCD shield. I'm not sure if it goes into an analog pins, or a digital pins. The connector has a green, red, and yellow wire. On the transmitter side, I have a Red/Green wire for +5v DC and GND. That side works just fine. Now I want to ensure what when I connect the receiver side, I don't do something that will harm the receiver.

If these sensors are analog, then I would assume I can connect them to the (5v, GND, S) pins and life will be good. If they are digital, then I may have to do something different. I appreciate any input.

Hope I explained this correctly and I thank you in advance for your answers!
Nick

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It's highly unlikely that these give an analog signal. Given no documentation, I would suggest:

Red: Connect to 5V
Black: Connect to GND
Yellow: Connect to any digital pin. The pin should show a change in state (high to low or low to high) when the beam is blocked.

Another example of these sensors: http://arduino-info.wikispaces.com/InfraredBeamPair

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Thank you for the reply and the input. I did a google search for the sensors yesterday and did not find that link. I will try what you suggest and I'm confident it will work without issue!

Thanks again,
Nick

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First, I have learned my lesson on buying anything from SainSmart! Their documentation sucks!

So, One more follow-up question. I have the 1602 v3 rev of the sainsmart board from my current research. As you can see in the attached pictures. I'm hoping someone has this board and can tell me what the 9 pins are on the top right of this shield. I am hoping they are digital sensor connections to attach the receiver above. However, my gut and testing with the multimeter does not yeild the expected voltages.

The only schematic I can find on their link above is very outdated(attached). If I go based on it, then J5 appears to be the female connector. However, I am not sure what the 9 male connectors are beside it. They are not listed. Does anyone have any insight? Thanks again!

1602v3-2.jpg

1602v3.jpg

LCDKeypad Shield SCH.pdf (46.5 KB)

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I found an updated schematic on the DFRobot page here. Arduino_LCD_KeyPad_Shield__SKU__DFR0009_-DFRobot

Based on that schematic I was able to verify that I can use the D0, gnd and vcc pins for my needs. I reversed the ground and +5 wires on the sensor and it works like a charm!

schematics-v1.0-dfr0009.pdf (48.4 KB)