Sparkfun: Mini Photocell - Revision history

Yoder: Fixed Grade

2012-10-03T19:59:06Z

Fixed Grade

Popenhjc: /* Bone Usage */

2012-10-03T18:48:45Z

‎Bone Usage

Popenhjc: /* Sample C Code */

2012-10-03T18:44:27Z

‎Sample C Code

Popenhjc: /* Bone Usage */

2012-10-03T18:16:50Z

‎Bone Usage

Popenhjc: /* Overview */

2012-10-03T18:16:35Z

‎Overview

Popenhjc: /* Bone Usage */

2012-10-03T17:50:47Z

‎Bone Usage

Popenhjc: /* Bone Usage */

2012-10-03T17:47:22Z

‎Bone Usage

Popenhjc: /* Bone Usage */

2012-10-03T17:43:59Z

‎Bone Usage

Popenhjc at 17:30, 3 October 2012

2012-10-03T17:30:38Z

Yoder: Added Grade

2012-10-03T17:05:07Z

Added Grade

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 [[Category:SparkFun]]
 <pre style="color:red">
-Overview:
+Comments: Good.  See other page for grade.
-Wiring:
-Code:
-git/Compiles with make:
-Demo:
-Total:
-Comments: Generally the same comments as your other sensor.
 </pre>

@@ Line 25: / Line 25: @@
 [[File:MiniPhotocellWiring.jpg|thumb|Wiring Example of MiniPhotocell]]
-To interface this with the BeagleBone you just need to connect the photo-resistor from the analog VCC to an analog input and another resistor (I used 1.1k&Omega;) from analog input to analog ground. From there you can read the voltage input and manipulate it using code however desired. In my case I basically took the number that the analog input gave me and manipulated it to work as the duty cycle for a pwm which dimmed the light if it was too bright and brightened the light if it was too dim. You can see this in the sample code provided. There is also a picture included of how to wire the photocell to the bone.
+To interface this with the BeagleBone you just need to connect the photo-resistor from the analog VCC to an analog input and another resistor (I used 1.1k&Omega;) from analog input to analog ground(on P9). From there you can read the voltage input and manipulate it using code however desired. In my case I basically took the number that the analog input gave me and manipulated it to work as the duty cycle for a pwm which dimmed the light if it was too bright and brightened the light if it was too dim. You can see this in the sample code provided. There is also a picture included of how to wire the photocell to the bone.
 == Reading and Interpreting Analog Input Data ==

← Older revision		Revision as of 18:44, 3 October 2012
Line 31:		Line 31:

	== Sample C Code ==		== Sample C Code ==
		+
		+	The following code can be found through github.
		+
		+	https://github.com/popenhjc/popenhjc_ECE497
		+
		+	You can do a git clone of this repository which includes MiniProject02 folder. Using the make command will make the two c files.
		+
	<pre>		<pre>

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 == Bone Usage ==
 [[File:MiniPhotocellWiring.jpg|thumb|Wiring Example of MiniPhotocell]]
 == Reading and Interpreting Analog Input Data ==

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 == Overview ==
 The [https://www.sparkfun.com/products/9088 product]. The [http://www.sparkfun.com/datasheets/Sensors/Imaging/SEN-09088-datasheet.pdf datasheet].
 This is a small sensor that changes resistance depending on the amount of light it is exposed to. The Photocell is also referred to as a photo-resistor, photo-detector, and photo-conductor.
 == Inputs and Outputs ==

← Older revision		Revision as of 17:30, 3 October 2012
Line 17:		Line 17:

	This is a small sensor that changes resistance depending on the amount of light it is exposed to. The Photocell is also referred to as a photo-resistor, photo-detector, and photo-conductor.		This is a small sensor that changes resistance depending on the amount of light it is exposed to. The Photocell is also referred to as a photo-resistor, photo-detector, and photo-conductor.
		+
		+	[[File:MiniPhotocell.jpg\|thumb\|Input and Outputs of Mini Photocell]]

	== Inputs and Outputs ==		== Inputs and Outputs ==

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 [[Category:ECE497]]
 [[Category:SparkFun]]
 == Overview ==
@@ Line 9: / Line 19: @@
 == Inputs and Outputs ==
-As for inputs and outputs, the sensor is basically a resistor and thus should be read from the analog input pins. To work with the analog input, you must put 1k ohm resistor from analog ground to the analog input you choose then connect the sensor from the analog VDD to the analog input you choose. The input voltage can then be read by the processor to interpret the amount of light in the room.
+As for inputs and outputs, the sensor is basically a resistor and thus should be read from the analog input pins. To work with the analog input, you must put 1k&Omega; resistor from analog ground to the analog input you choose then connect the sensor from the analog VDD to the analog input you choose. The input voltage can then be read by the processor to interpret the amount of light in the room.
 == Bone Usage ==
-To interface this with the BeagleBone you just need to connect the photo-resistor from the analog VCC to an analog input and another resistor (I used 1.1kohms) from analog input to analog ground. From there you can read the voltage input and manipulate it using code however desired. In my case I basically took the number that the analog input gave me and manipulated it to work as the duty cycle for a pwm which dimmed the light if it was too bright and brightened the light if it was too dim. You can see this in the sample code provided.
+To interface this with the BeagleBone you just need to connect the photo-resistor from the analog VCC to an analog input and another resistor (I used 1.1k&Omega;) from analog input to analog ground. From there you can read the voltage input and manipulate it using code however desired. In my case I basically took the number that the analog input gave me and manipulated it to work as the duty cycle for a pwm which dimmed the light if it was too bright and brightened the light if it was too dim. You can see this in the sample code provided.
 == Reading and Interpreting Analog Input Data ==
-The resistance of the Mini Photocell is interpreted as such. When there is a very dim room the resistance shoots up to 10Mohms, but normal ranges occur anywhere from 8 to 20kohms. So, the lower the number the analog input pin says it is, the darker it is in the room, with the set up explained in the previous section.
+The resistance of the Mini Photocell is interpreted as such. When there is a very dim room the resistance shoots up to 10M&Omega;, but normal ranges occur anywhere from 8 to 20k&Omega;. So, the lower the number the analog input pin says it is, the darker it is in the room, with the set up explained in the previous section.
 == Sample C Code ==