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16  Using Arduino / Displays / Re: HD44780 LCD Backlight control with PWM on: May 31, 2012, 03:11:29 am
Docedison - this thread's over a year old now - I think they've probably got something working!
17  Using Arduino / Displays / Re: HD44780 LCD Backlight control with PWM on: May 27, 2012, 02:28:10 pm
Older than me then! smiley-grin
18  Using Arduino / Displays / Re: HD44780 LCD Backlight control with PWM on: May 27, 2012, 01:11:47 pm
I'm thinking that's probably their own website and or/they're a spammer.

Ahh well.

Thanks for the interesting additional info on HD44780 controlled displays though. I wasn't aware the controller had been floating around for so long!
19  Using Arduino / Displays / Re: HD44780 LCD Backlight control with PWM on: May 27, 2012, 10:07:32 am
Is that really a satisfactory reason to drag up such an old thread?  smiley-razz

*Some* LCDs have a resistor inline with the backlight but some don't. That depends completely on the LCD and looking at the specific datasheet for your LCD will tell you if it does or not.

This thread was also discussing pulse width modulation of a pin to dim the backlight, not simply powering it.
20  Using Arduino / Motors, Mechanics, and Power / Re: UK PowerSwitch Tail Alternative on: December 19, 2011, 11:48:41 am
How old are your students?
Pretty sure all students in the UK are taught how to re-wire a plug in Physics at secondary school.

I would say it's safe enough to get them to do but as the wiring colour scheme will be different (the US don't use brown, blue and yellow-green), you'd possibly be better to do it yourself.
You would need somebody trained to check all of the re-wiring before they're to be used and this would likely include PAT testing which would be necessary if you are then going to use the devices in school.

I would check up with the school/college/university about what you're allowed to do - they can be very against people doing anything with voltages above what a desk supply can provide.
21  General Category / General Discussion / Re: Arduino User Map on: November 14, 2011, 12:15:40 pm
Quote
That's the only place where I show up.
Yeah I know :/
22  General Category / General Discussion / Re: Arduino User Map on: November 14, 2011, 09:58:59 am
Ok anyone got any better suggestions of where we should have this map as it's become apparent Google Maps is useless.

I can't seem to get on the second page, it's only showing some people and just generally not working right.
23  Development / Other Hardware Development / Re: 7 segment shift register backpack on: November 13, 2011, 04:02:33 am
Haha - glad I'm not the only one complaining to bld about 90 deg angles on tracks.
24  Development / Other Hardware Development / Re: 7 segment shift register backpack on: November 12, 2011, 01:53:06 pm
Should have used a 0.1" grid... smiley-grin
25  General Category / General Discussion / Re: Arduino User Map on: November 12, 2011, 11:04:16 am
Yeah it seemed bit broken to me earlier too so I just left it and decided I'd have another go another day.
26  General Category / General Discussion / Re: Arduino User Map on: November 12, 2011, 05:59:18 am
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I added myself several times, but it didn't stick.
Well you're on there 3 times smiley-wink

Lets have a clean-up.
27  Community / Bar Sport / Re: Chinese Laser Cutter Modifications on: October 19, 2011, 12:42:10 am
My only concern so far with your mods is the replacement of the window; that amber color is likely a filter for the wavelength of the laser, so that any spurious reflections while looking at the cutter work don't damage your eyes. Then again, that's just a guess (based only on using special safety glasses/goggles with a 200mW green laser pointer).

I might have to check ebay again - see how much the prices have come down since I last looked...

Well, I just looked - and prices are down; really down since the last I looked. Your particular machine costs about $800.00 USD (+s/h); 40W laser tubes can be had for around $150.00 USD (+s/h). Much better pricing from when I last remember; of course, those prices are "drop-shipped from china" - and I don't quite trust dropping nearly a bill to a chinese supplier (I might be willing using escrow, though - did you use an escrow service?). I did find one guy selling from florida - but he only had local pickup (no shipping). Interesting, all the same - can't wait to hear how your mods and such turn out!

smiley
Re. window colour, everyone seems to make that comment smiley-wink with an IR CO2 laser such as this it's the acrylic that stops the laser radiation, if it was a visible wavelength then it would most likely pass straight through the window but as it is, 6mm of clear is probably safer than 3mm of amber coloured dubious quality Chinese acrylic.
The amber colour reduces glare but I'm not stupid enough to stare at the burning material constantly smiley-wink
And going back to the clear window, look at universal or epilog laser cutters - you don't see any silly coloured window do you smiley-wink

Re. pricing, yes they have gone down a lot, I was rather surprised when I found I could get one so cheap. Mine was actually sent from the UK rather than direct from China, a lot of the sellers seem to have multiple places they ship from, look in the item description.

So lots more mods to come still, I think my honeycomb arrived yesterday as I have a suitable sized box waiting to be opened but unfortunately I was rather I'll yesterday so will probably spend most of today in bed :/
28  Community / Bar Sport / Re: Chinese Laser Cutter Modifications on: October 17, 2011, 04:29:12 pm
Quote
some power tests?
What do you mean?

It's stated as a 40W tube (maybe 40W if I keep it a decent cool temp) and it seems somewhere near that from the holes I've made so far (I've used a 60W and an 80W laser cutter before).
The unit itself is rated as 250W but I'll measure that at some point when I have it running.
29  Community / Bar Sport / Re: Chinese Laser Cutter Modifications on: October 17, 2011, 04:24:42 pm
Well I shot some holes through a few thin paper pads and some acrylic but no not really - the controller board and software is pretty crap so once I've done my mods I'll likely be replacing that stuff anyway. I know the steppers work fine as homing worked fine so with that and the laser burning through stuff I'm happy enough that it works.

I didn't think I'd have the thing for another few weeks so I'm fine not using it - the mods are just as fun as making stuff.

There's a lot more to come mods wise - what I've done so far is minor...
Just removed the whole X/Y assembly tonight and the secondary mirror and tertiary mirror/lens setup ready for relocating smiley-wink
30  Community / Bar Sport / Re: Chinese Laser Cutter Modifications on: October 17, 2011, 03:49:42 pm
Works here but edited, try that.

And what about the pics in the CNCzone forum? (they're linked straight from it)
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