Hey Ricardo - Hmmm... you may need to stick with SPAD II for the moment. I'm not sure what calibration values are on your machine, but 74 is a bit old... best way to learn is if you can run SPAD II and SPAD III and post the images so I can see, and if possible send a link to the actual data page (if you collect the data in a project, you can link the project and I'll take a look). That would help.

You probably need batteries - pop off the back cover and you'll see 6 rechargeable batteries. Recharge them and try again!

Greg, We made some measurements in a project called Prueba SPAD II y III (we linked it with you), bellow we pasted the screenshots. As could see there is no data in non of the protocols (SPAD II and III).

Susana, Your device was never calibrated for the SPAD II or SPAD III protocols. The calibration data would appear in the 'user def' below the traces in the screenshots above.

The SPAD I protocol does not require calibration, but this protocol can lead to large device to device variation. Also, this protocol only uses one light intensity , so it does not work well with either very thin or very thick leaves.

We usually calibrate against the Minolta SPAD meter. If you have access to a SPAD meter other than MultispeQ, I can help you get the device calibrated. Otherwise, we can come up with another method to calibrate your device.

Dan

Hi Dan, no, we did not calibrate for SPAD II and III protocols. We have a minolta spad meter, we'll appreciate it very much if you could help us to do it.

Susana, to calibrate your MultispeQ:

1. Print out the two attached files onto 1 sheet of paper. You will have to print them so that each numbered color box is lined up on both sides of the paper.

2. Fold the appropriately marked color boxes. This is important for adjusting for leaf thickness

3. Take 3-5 measurements from each color box (#'s 3-11, ignore the SPAD values that are on the SPAD Cal side 1 sheet) using a SPAD meter (e.g. Minolta). Record the average for each of the colored boxes

4. You will need to use the Google Chrome version of the PhotosynQ app for calibration (if you do not have it, it is available in the chrome web store: https://chrome.google.com/webstore/category/apps?utm_source=chrome-ntp-icon)

5. Go to photosynq.org and join the project "Calibration: Blank and SPAD II."

6. Open up the PhotosynQ chrome app, log-in and synchronize the app (double arrows icon at top of app) to make sure that the calibration project appears in projects tab (left).

7. Connect the MultispeQ device (plug icon at top of app).

8. Open up the Calibration project and follow the instructions. You will need to enter the Minolta value's in the appropriate prompts that pop up during the calibration project. At the end of the calibration you will need to submit the data to the device (airplane icon) and keep the data (but only after checking the calibration, below).

9. To check if the calibration worked, there are 2 things to look at. A. There will be an r value for each PQ.SPAD 1,2, and 3. This r value should be at or very near to 1 and B. check the trace to make sure that none of the lines hit 0k or 64k on the y-axis of the graph.

Susana,

I see that you calibrated your device. The r2 for PQ1 is too low (0.9) and will result in poor SPAD values. Looking at the trace, it appears that the first 'blank' in the calibration protocol was too close to zero. Did you test this blank with no paper in the chamber or did you have panel 0 in the chamber? This blank needs to be done with nothing in the measuring chamber.