light sensors

Post by **Willem4ever** » Mon Dec 11, 2006 7:49 pm

I'm looking for a device to measure light, ideally it should report in (k)lux, however for my intended purpose their is not really a need for something which is properly calibrated.

Post by **bjorn** » Mon Dec 11, 2006 8:55 pm

I am also interested in light sensors. I am thinking of creating something similar to the 1-wire solar radiation sensor on Hobby Boards, http://www.hobby-boards.com/catalog/lin ... iation.pdf, but using a photo diode that is optimized for visible light, something like the Sharp BS120E0F (search for this part on for example http://nl.digikey.com).

For me the primary purpose will be to control dimmers in the house so that the light level stays constant at the adjusted level at all times. I have no experience of this and haven't seen it in practice anywhere so I am looking forward to experiment with it.

Post by **b_weijenberg** » Mon Dec 11, 2006 10:43 pm

willem4ever/bjorn,

I have connected a BPW85 http://www.vishay.com/docs/81531/81531.pdf and a 10k resistor to the A/D input of an RFXSensor (40063,64,65,66 or 60011)

.|---VDD
.|
| |
| | 10k
| |
.|---- A/D
.|
..\ collector
...| BPW85
../ emitter
.|
.|--- GND

This is the output from the A/D input for the different light situations:

Dark results in 4.9Volt
A001F13D4A RFXSensor addr:01F1/497 RH:131,94% Barometer:1192hPa Voltage:4,9 bits=32 from SLAVE
A001F13D4A RFXSensor addr:01F1/497 RH:131,94% Barometer:1192hPa Voltage:4,9 bits=32 from SLAVE
A001F13D4A RFXSensor addr:01F1/497 RH:131,94% Barometer:1192hPa Voltage:4,9 bits=32 from SLAVE

About half dark results in 3.4Volt
A001F12A8A RFXSensor addr:01F1/497 RH:84,09% Barometer:863hPa Voltage:3,4 bits=32 from SLAVE
A001F12A8A RFXSensor addr:01F1/497 RH:84,09% Barometer:863hPa Voltage:3,4 bits=32 from SLAVE
A001F12A8A RFXSensor addr:01F1/497 RH:84,09% Barometer:863hPa Voltage:3,4 bits=32 from SLAVE

Full light results in 0.4Volt
A001F10509 RFXSensor addr:01F1/497 RH:-12,88% Barometer:195hPa Voltage:0,4 bits=32 from SLAVE
A001F10509 RFXSensor addr:01F1/497 RH:-12,88% Barometer:195hPa Voltage:0,4 bits=32 from SLAVE
A001F10509 RFXSensor addr:01F1/497 RH:-12,88% Barometer:195hPa Voltage:0,4 bits=32 from SLAVE

The A/D input can also be used for a humidity or barometric pressure sensor or any DC voltage up to 10volts.
The RFreceiver program calculates the HR and hPa using the A/D voltage and displays the calculated values in case a HR or hPa sensor is connected to the A/D input. These values can be ignored because the value is the BPW85 voltage now.

Bert

Post by **Willem4ever** » Tue Dec 12, 2006 1:34 pm

Hi Bert,

Thanks for the idea, this solution could suffice. Measuring light in e.g. the livingroom to switch on the light around sunset depending on the conditions of that particulair day.

Cheers, Willem.

Post by **b_weijenberg** » Tue Dec 12, 2006 3:37 pm

Willem4ever,

In the RFXSensor you can select the sample rate to 1 minute or 5 minutes. This is for your requested solution OK.
The RFXSensor has a temperature sensor, an A/D sensor and the supply voltage sensor and all 3 are available. So you can measure the room temperature with the same device.

Bert

Post by **Han** » Tue Dec 12, 2006 6:20 pm

Hi,

I have build an X10 unit which transmits temperature and light. It makes use of the X10 extended code 1 protocol. (for spec see: http://www.domoticaforum.eu/topic.asp?T ... Terms=TL01).
As a light sensor I use a Silonex NSL-06S53. It is connected to the AD input of a PIC processor (using an emmitter follower in between).
You can find the transfer characteristic in the TL01 spec. In the conrol software (Zeus), I have used a translation table to translate to Lux and Degree C values.
Regards,

Han Alink

Post by **Willem4ever** » Tue Dec 12, 2006 7:31 pm

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Han
 Hi,

I have build an X10 unit which transmits temperature and light. It makes use of the X10 extended code 1 protocol. (for spec see: http://www.domoticaforum.eu/topic.asp?T ... Terms=TL01).
As a light sensor I use a Silonex NSL-06S53. It is connected to the AD input of a PIC processor (using an emmitter follower in between).
You can find the transfer characteristic in the TL01 spec. In the conrol software (Zeus), I have used a translation table to translate to Lux and Degree C values.
Regards,

Han Alink
<hr height="1" noshade id="quote"></blockquote id="quote">

Hi Han,

I followed the link, that seems interesting, you also mention you have spare pcb's for this device. Can you contact me via email willem4ever at yahoo dot co dot uk

Many thanks,

Willem.

Post by **Stoommaaltijd** » Sat Feb 10, 2007 2:20 pm

Hi all.

I am also very much interested in a lightmeter (giving access to some light 'value' that you can test on in Homeseer) but... although I would be able to solder something together... I would need exact instructions on how to do it and exactly what to get. Ideally I'd buy a ready made module but I undestand such doesn't exist (yet).

The references to other topics makes my head spin (lengthy discussions about controlling heating systems etc) but perhaps I am asking too much.

Anyway, any instructions for simpletons would be appreciated!

Take care,

Eric