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by RoMZERO
Sat Nov 07, 2015 7:32 pm
Forum: Beginners
Topic: ATX power supply
Replies: 2
Views: 811

ATX power supply

Dear all,
I want to use a old ATX as power supply for the RPi.
My old ATX has a 5v (30A) output. Is this output safe for my the RPi or is there the risk to damage the hardware?

Thank you in advance.

Best regards,
Roberto
by RoMZERO
Fri Oct 23, 2015 4:50 pm
Forum: Automation, sensing and robotics
Topic: Humidity sensor and air dryer
Replies: 13
Views: 2555

Re: Humidity sensor and air dryer

I think that I solved my problem (I performed some tests) by substituing the air dryer with a saturated salt solution. Right now the raspberry pi is inside a sealed box with a 400-mL potassium carbonate salt solution. As explained by Greenspan (1976)*, potassium carbonate should be able to maintaine...
by RoMZERO
Tue Oct 20, 2015 12:33 pm
Forum: Automation, sensing and robotics
Topic: Humidity sensor and air dryer
Replies: 13
Views: 2555

Re: Humidity sensor and air dryer

This is the dryer. http://www.amazon.co.uk/dp/B000BP81DW/ref=asc_df_B000BP81DW29538786/?tag=googshopit-21&creative=23390&creativeASIN=B000BP81DW&linkCode=df0&hvdev=c&hvnetw=g&hvqmt= The distance between the dryer and the sensor is about 1 m (I need this distance because of a further experiment in a ...
by RoMZERO
Tue Oct 20, 2015 6:29 am
Forum: Automation, sensing and robotics
Topic: Humidity sensor and air dryer
Replies: 13
Views: 2555

Re: Humidity sensor and air dryer

The door was closed all the time. I monitored the sensor results via plotly (the website).

I just opened the door during some additional tests.
by RoMZERO
Mon Oct 19, 2015 10:19 pm
Forum: Automation, sensing and robotics
Topic: Humidity sensor and air dryer
Replies: 13
Views: 2555

Re: Humidity sensor and air dryer

I monitored the temperature too and it is stable. No changes in temperature were measured by the sensor. I noted tha spikes were significantly lower in case of the door of the room was partally opened. Thus, I suppose that no EM emission was responsible for what I measured. It is a really strange be...
by RoMZERO
Mon Oct 19, 2015 7:35 pm
Forum: Automation, sensing and robotics
Topic: Humidity sensor and air dryer
Replies: 13
Views: 2555

Re: Humidity sensor and air dryer

Do you think that the air dryer changed the air pressure inside the room and so the dew point?
by RoMZERO
Mon Oct 19, 2015 4:28 pm
Forum: Automation, sensing and robotics
Topic: Humidity sensor and air dryer
Replies: 13
Views: 2555

Humidity sensor and air dryer

Dear all, I am playing with some sensors and raspberry Pi. I bought the DHT22 sensor with the aim to monitor the room temperature and the relative humidity of a closed space. To deeply test the sensor, I turned on an air dryer into a room. The results were very strange: every time the air dryer star...
by RoMZERO
Thu May 14, 2015 10:02 pm
Forum: Camera board
Topic: Consistent color measurement
Replies: 11
Views: 2337

Re: Consistent color measurement

Hi all, I did an additional test. I acquired images every 30 sec for 10 min by turning the light on 2 seconds before the image acquisition. Thus, it is impossible that the lights were heated. Here the plot: luminance_3.png The plot is pretty clear: the camera goes "dark". I will perform the tests yo...
by RoMZERO
Mon May 11, 2015 7:24 pm
Forum: Camera board
Topic: Consistent color measurement
Replies: 11
Views: 2337

Re: Consistent color measurement

Dear all,
Thank you for your advice. I will perform some additional test as soon as possible.

Here in attach an example of a decreasing in luminance that I noted
Luminance.png
Luminance.png (9.33 KiB) Viewed 2175 times
Edit:
here another example
luminance2.png
luminance2.png (14.94 KiB) Viewed 2175 times
by RoMZERO
Mon May 11, 2015 5:45 am
Forum: Camera board
Topic: Consistent color measurement
Replies: 11
Views: 2337

Re: Consistent color measurement

I have a constant-current driver and the LEDs require 12V. The ATX DC provides a stable current over time when lights are on (I measured it). I do not use ballast resistors. The light source are similar to those shown in the following image http://www.ledworld.it/public/zoom_24822304_LS3116_04.jpg T...
by RoMZERO
Mon May 11, 2015 4:24 am
Forum: Camera board
Topic: Consistent color measurement
Replies: 11
Views: 2337

Re: Consistent color measurement

Hi, thank you for you answer. Of course, I already turn off the exposure time. At a early stage of my script development, I noted that shutter speed and exposure time tended to different values (exposure time gradually decreased over time). After both software and firmware updates exposure time seem...
by RoMZERO
Sun May 10, 2015 4:18 pm
Forum: Camera board
Topic: Consistent color measurement
Replies: 11
Views: 2337

Consistent color measurement

Dear all, I am working on a little project with the aim to build a colorimeter by using raspberry pi + python + opencv. The colorimeter will be used to acquire images every 30 seconds for detecting changes in color of a food matrix. Unfortunately, I have a big issue with the raspberry pi camera due ...

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