Actions
Forum Thread Details
  • State Suggested Answer
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 52 subscribers
  • Views 988 views
  • Users 0 members are here
Related

I need advice on a project.

mikedavis

Everyone,

 

I have an idea for a project, and I need some assistance. 

 

I would like to use the RPi (or whatever is most appropriate) to create a light detector.

 

A long time ago, I built a circuit that had a cadmium selenide detector.  When light hit it, there was a change in its resistance, and I could use the difference between the voltage in and the voltage out to determine how much light the detector was seeing.

 

I have breadboard that I can use to get the circuit going.  I would like to be able to use the RPi to have a computer capture this information so I could run an experiment over a long period of time.

 

What materials would I need?

 

Mike Davis

Parents
  • 0

    Mike, a couple of suggestions:

     

    Keep your circuit mostly as-is and use an I2C (or SPI) ADC chip to read the change in the LDR in place of a simple analogue meter. There are plenty of ADC's available with different resolutions and sampling speeds, perhaps something like this ADC081C027CIMK/NOPB - IC, 8BIT ADC, I2C, SAR, TSOT23-6ADC081C027CIMK/NOPB - IC, 8BIT ADC, I2C, SAR, TSOT23-6

     

    Another way might be to use a specific light sensor like TSL2550DTSL2550D   

     

    Either way, and as DAB suggests, you'll need to make sure the device you chose has the required sensitivity.

     

    Both of those suggestions could be interfaced directly to an RPi, or to an Arduino. Reading them at set intervals and writing the results to somewhere useful is simply a matter of writing some code to do it.

Reply
  • 0

    Mike, a couple of suggestions:

     

    Keep your circuit mostly as-is and use an I2C (or SPI) ADC chip to read the change in the LDR in place of a simple analogue meter. There are plenty of ADC's available with different resolutions and sampling speeds, perhaps something like this ADC081C027CIMK/NOPB - IC, 8BIT ADC, I2C, SAR, TSOT23-6ADC081C027CIMK/NOPB - IC, 8BIT ADC, I2C, SAR, TSOT23-6

     

    Another way might be to use a specific light sensor like TSL2550DTSL2550D   

     

    Either way, and as DAB suggests, you'll need to make sure the device you chose has the required sensitivity.

     

    Both of those suggestions could be interfaced directly to an RPi, or to an Arduino. Reading them at set intervals and writing the results to somewhere useful is simply a matter of writing some code to do it.

Children
No Data