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481  Using Arduino / Installation & Troubleshooting / What to do next? Uno not working - won't program on: January 30, 2012, 06:41:24 am
Hi all, I have had an Uno for a few months now. During this time I have had a nightmare getting code on the board - avr not in sync, com port not found, usb device not recognised etc etc. I think it has probably worked 25% of the time which makes working with it very stressfull. I have tried multiple PC's - same issue. The uC works because I can see it running code if I manage to ever get some on there!

I recently bought a Nano clone however and that works 100% of the time on the same PC's which I'm really happy about.

What should I do / try with the Uno?
482  Using Arduino / Displays / Re: Easy way to dim parallel LCD backlight with a photoresitor on: January 29, 2012, 06:55:06 pm
ok, so I have decided on 1k to 200k.

I'm not great at maths, but I think I have got this...

square of 1,000 x 200,000 = 200,000,000

square of 200,000,000 = 14142.... so 14k?

Thanks for the help  smiley
483  Using Arduino / Displays / Re: Easy way to dim parallel LCD backlight with a photoresitor on: January 28, 2012, 07:08:14 pm
I have just had a look at the ldr. I measure it from around 40 (infront of a 10w LED) to 20m ohms (in pitch black).

is there a simple formula for selecting the right value res to use in the divider?

I'm a little confused because the datasheet says 20k to 2m ohms but I don't measure that?

Thanks  smiley
484  Community / Exhibition / Gallery / Re: IR remote and RGB diodes on: January 25, 2012, 10:26:47 am
looks great, good work!
485  Community / Exhibition / Gallery / Re: Benchtop power supply and outlet / other homemade power supplies? on: January 25, 2012, 10:07:08 am
looks good mate, and very usefull!

How accurate are your voltages? I tried making one a while ago but even with a small load I could not keep the 12v rail above 12v
486  Community / Website and Forum / Re: Completed projects form on: January 25, 2012, 09:26:12 am
Oh, silly me thanks for pointing that out!
487  Community / Website and Forum / Completed projects form on: January 25, 2012, 08:37:57 am
Hi all, I think it might be a nice idea to have either a project build forum or completed project forum.

The first would be a place for people to document their projects from start to finish, and the latter would be a place where people document their projects once they have been completed.

488  Using Arduino / Displays / Re: LCD does not work unless Arduino is reset. on: January 24, 2012, 10:18:13 am
Just bumping this thread to the top because I still have the same issue with initialization, maybe someone who has not seen it has some suggestions?

489  Using Arduino / Displays / Re: Easy way to dim parallel LCD backlight with a photoresitor on: January 24, 2012, 10:03:35 am
Thanks so much DC smiley

Would this be a suitable LDR? http://uk.rs-online.com/web/p/ldr/0596141/

Sorry for the noob questions but I have never used them before  smiley
490  Using Arduino / Displays / Re: Easy way to dim parallel LCD backlight with a photoresitor on: January 18, 2012, 01:05:47 pm
Thanks for the help  smiley

what would be a SMD equivalent if I decide to go down the smd route?

Thanks again
491  Using Arduino / Displays / Re: Easy way to dim parallel LCD backlight with a photoresitor on: January 09, 2012, 10:27:36 am
thank you all for the help, that's great.

@dc42 - why do you need to use a 1K resistor? and how did you come to this value? I'm not questioning your intelligence in any shape or form I just like to learn smiley

excellent I will set it up as a divider then smiley

Because the resistance swing is so great, how would I calculate the value of the other resistor in the divider?

many thanks
492  Using Arduino / Displays / Re: Easy way to dim parallel LCD backlight with a photoresitor on: January 06, 2012, 07:16:39 am
Thanks liudr thats a good point. Just looking at the datasheet for my screens and I think they draw 120mA at max!

Any recommendations on a transistor? I guess it would have to be a fast one if I am to use PWM?

Thanks
493  Using Arduino / Displays / Re: Easy way to dim parallel LCD backlight with a photoresitor on: January 05, 2012, 06:44:02 am
thanks for the link, which bit do you suggest looking at?

the only relevent bit that I can see is 'Theremin – Use a photocell & piezo as a theremin' but I have no idea what that is doing, or what a theremin is?

Thanks kindly
494  Using Arduino / Displays / Re: Easy way to dim parallel LCD backlight with a photoresitor on: January 04, 2012, 05:50:49 pm
http://www.rapidonline.com/Electronic-Components/Light-Dependant-Photoresistor-58-0134/?sid=53bc3fcf-5ffd-4335-aea8-a7850ab2d13f

just looking at the above, I guess the resistance swing would be from 1m ohm to 2-4k ohm, what would be the best way to use that? or are there more suitable ranges? Would I set it up as a voltage divider or directly to one of the analogue inputs?

495  Using Arduino / Displays / Easy way to dim parallel LCD backlight with a photoresitor on: January 04, 2012, 03:11:22 pm
Hi all,

I saw somewhere on here (cant remember exactly where) that someone had set up a photo resistor to measure amibent light and dim the LCD's back light accordingly.

I really like this idea and I would like to try it out.

I use LCD's in parallel mode (not yet tried a serial one). I guess the code should be pretty simple - analogue read on the photo resistor, and set it to vary the voltage on a analogue output pin?

I'm unsure on the coding and what type (and where to look) photo-resistor to use?

Thanks in advance smiley
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