Hobby Boards Solar Sensor with the Labjack

Hardware Weather Station Equipment
1

I recently received a labjack which I am now using for an extra temperature sensor. I would like to add the solar sensor from hobby boards (http://www.hobby-boards.com/1wireboards/sr2-r1_solar_radiation.html). I have searched through the posts but I could not come up with a clear answer (or my searching skills leave something to be desired). Will this work directly with a labjack or does it require some type of modification. It seems that I have seen someone’s signature that lists their equipment and says something about a labjack with “modified” solar sensor.

If I order this from Hobby Boards, can I just plug it in to my cat5e with the appropriate connections and have it work with the labjack? It also appears that because of the overloading of this sensor and possibly its narrow viewing angle (?) I should find a diffuser such as this one: http://www.mouser.com/index.cfm?&handler=data.listcategory&D=White%2btranslucent%2blens%2b*%2360625P307W*&terms=White+translucent+lens%2c++%23606-25P-307W&Ntt=White%2btranslucent%2blens%2b*%2360625P307W*&Dk=1&Ns=MfgrPartNumber%7c%7cSField&N=0&crc=false

I put all these together in a mount of some type (a section of PVC pipe?), determine my max voltage for solar noon, and all is happy?

Thanks for any input…

2

hi
yes, you can get it to work with the labjack…not sure what mod needed.,…ricky has this working…he is a forum member (but I think he is on holiday camping at the moment (he is from NZ)
and yes the diffuser is needed
in the solar setup,you can then select to use the labjack…and you then set the max volts…
with the labjack, you wire it into say AI3 (i.e anolog input 3), and +5v

3

I had a quick look at the hoby boards design… to use with the Labjack you would only need the sensor Diode itself and a resistor, not any of the other circuitry…

Their design makes use of the very low voltage measuring capability of that Dallas Battery monitor IC, so they use a small value resistor, with the labjack it would need to be a higher value to get a decent voltage from the sensor diode current…

so, you could connect the sensor diode from labjack +5V to an AI terminal, and try a variable resistor of maybe 100k from AI to GND, adjusted until you get a few volts with full sun.

because of the high impedance, the wire to the sensor could be susceptible to interference, so I would add a capacitor of maybe 0.1uF across the resistor and use sheilded pair cable with the sheild connected to GND…
Ideally you would have a buffer amplifier at the sensor feeding the cable, but that would take a little more design…

I have found that the Labjack has some internal leakage current to its analog inputs which could upset readings with this setup… could be that I damaged mine at some stage though lol

Here I Use a very simple arrangement with a small 1W 6V solar (PV) panel with a load resistor feeding an input… crude and overkill but it works

Actually what would be good brian, would be to add a decimal place to the max volts setting in the solar setup, to make calibration more accurate too :slight_smile:

4

That’s a great idea, you can get a little solar cell from Radio Shack and you’re in business. Overcomes the view angle issues of the hobby boards one too.

5

Are they still around? They disappeared from the UK some time ago. Luckily Maplins have opened a store in Blackpool now, so I can still buy electronic components if/when I want to.

Does WD support the USB based LabJack? The Ethernet version is quite expensive (

6

I use the USB based Labjack, talks to WD with no problems and I have the simple solar sensor described, using a solar panel and a resistor. Call it

7

Sounds interesting and perhaps a project for later in the year when my credit card has recovered from the shock of Xmas!

What kind of wiring do you use between the sensor and the Labjack, e.g. screened cable, or doesn’t it matter too much?

8

type of cable really doesnt matter at all with this setup… :slight_smile:

9

Some of my cable runs could be quite long…that’s why I went with a wireless station when I moved into this house. I guess with a solar cell generating a reasonable effectively DC voltage it’s not too much of a problem, but I assume that sensors generating lower voltages might need better cables.

10

Chris, the temperature sensors I use, give a voltage from 0 Kelvin, so 2.85 Volts = 12.7C (Multiply by 100 and subtract 273.15)
I have noticed that the accuracy is only 0.5C, however in the future, if we can persuade Brian to use the LabJacks built in Gain controls, then we could up the accuracy by a factor of 5 and get 0.1 degree accuracy, However in order to use the gain, you need to utilise 2 analogue inputs for each sensor and the Labjack only has 8 analogue sensors.