3 QRD1114+Button+Arduino+Mini Breadboard+HELP!

Development Boards Arduino
1

Hello Sparkfun peeps!

I’m working on a project that surpasses my knowledge of electronics, and I need your help!

I connected 1 QRD1114 IR emitted / Phototransistor as per this tutorial, http://bildr.org/2011/03/various-proxim … s-arduino/ with the exception that I added a push button. Please consult the image bellow to see my setup:

http://picpaste.com/pics/qrd1114_Button … 338837.jpg

If the image does not show up in the post, please follow this link http://picpaste.com/pics/qrd1114_Button … 309799.jpg

I am not able to figure out the best way to connect 3 QRD1114 on my mini breadboard, along with the push button and required resistors.

The most important aspect for this project is that I need to get independent readings from each QRD1114 unit. I’m guessing that each should be on a different analogue pin, no? Also, the push button should not interrupt any activity or readings from the 3 QRD1114 units. The button should simply be recognized when pushed.

I’m concerned with the proper resistors to use. I’m still a noob with electronics and did not find a way to properly evaluate the resistance needed, taking into consideration the QRD1114 specs https://www.sparkfun.com/datasheets/BOT/QRD1114.pdf

A mate from the Arduino forums replied to the above with the following:

“Each QRD1114 has two terminals connected to Ground, one connected through a 200 Ohm resistor to +5, one connected through a 5.7K resistor to +5 and also to an analog input. The only difference between your four units would be which analog input they connect to”

I’m not quite sure I get it:

Can I use the resistor setup used for one QRD1114 for all three units and simply connect each unit on a different analogue pin? So, only one 200 Ohm + one 5.7K resistor for all three QRD1114 units? A serial connection?

2 resitors: 200 Ohm + 5.7K

3 QRD1114 units on 3 analogue pins

Or

Each single QRD1114 unit needs to have the resistor combination of one 200 Ohm + one 5.7K and each unit connected to a unique analogue pin? A parallel connection?

6 resistors: three 200 Ohm + three 5.7K

3 QRD1114 units on 3 analogue pins

Thank you for reading my post and I look forward to your replies!

Heff

2

You would need separate resistors for each sensor. Just wire up three identical circuits. The only difference, as you mentioned, is that each one would connect to a different analog input pin. +5 and GND is the same for all three.

/mike

3

Hi mike,

Thank you very much for the reply :slight_smile:

I’m going to apply all the great advice I received and update the thread with relevant info, and progress that might help others working with a similar setup.

Cheers!

Heff