Search found 87 matches

by Viking
Fri Jul 18, 2008 9:47 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 42101

Hello Federico, Using the MAX335, the absolute maximum theoretical time needed to write to every pixel in the display is around 2.5mS. This doesn't take into account the delay for signals to travel the considerable distance of the display (about 25x25feet if it is square). At a guess it would be pos...
by Viking
Fri Jul 18, 2008 3:53 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 42101

Hello Federico,

I will put together some suggested layout for this, over the coming days, which may give you some ideas.

Regards
Rob
by Viking
Thu Jul 17, 2008 11:35 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 42101

Hello Federico Yes, your supply voltage must always exceed or equal the voltage being switched. So you would need a +15 and -15 supply and +5V for the logic section. Your AC supply should be arranges so that the common input pin swings both positive and negative with respect to the pixel display com...
by Viking
Thu Jul 17, 2008 10:49 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 42101

Hello Federico, I went on the web site. Very glossy, zero technical information! So I'm going to have to guess that it would be driven in the same way as a standard LCD. The MAX335 can only handle a maximum of +/-15V, so you would probably want to go for the type that operates on 10V AC. I will need...
by Viking
Thu Jul 17, 2008 10:15 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 42101

Hello Federico The switch section of the IC is effectively isolated from the logic side, so the two don't interact. You would connect all the COM pins of all the MAX335 chips to the AC signal, and connect each NO line to individual pixels. I haven’t studied the properties of the display all that w...
by Viking
Thu Jul 17, 2008 9:09 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 42101

Hello Federico, I'm a little confused as to why you should want to convert DC to AC. As far as I can see, you intend to take the DC output of each MAX335 switch (this chip is in effect just 8 serially controlled on-off switches) and convert to AC. This would mean that you would need a converter for ...
by Viking
Fri Jul 11, 2008 3:52 am
Forum: General Discussion
Topic: brighten 12v light (LED?) over 2 minutes; low voltage trigge
Replies: 15
Views: 7757

Hello Bryan, Let me know how it turns out. I’m still available if you need anything designing/building. On the subject of the LED illumination, I think you would still be looking at 30-40W power consumption. If a 110W lamp lasts 10 days, then the system will run for about a month maximum on the sa...
by Viking
Thu Jul 10, 2008 8:36 am
Forum: General Discussion
Topic: brighten 12v light (LED?) over 2 minutes; low voltage trigge
Replies: 15
Views: 7757

Hello Lyndon We have covered this one in post 2 and 3:- "Just one thought...have you considered infra-red illumination? Would obviously be invisible to the wildlife so no problem with sudden switch-on, but would produce essentially mono-chrome pictures, which might be the reason for you having disco...
by Viking
Thu Jul 10, 2008 3:58 am
Forum: General Discussion
Topic: brighten 12v light (LED?) over 2 minutes; low voltage trigge
Replies: 15
Views: 7757

Hello Bryan, It would not be difficult to daisy-chain a load of linear drivers together, with the first one as the master. Actually this would make quite a good lighting effect, which could be usable in other applications. I suspect that the light needs to come on very slowly , and then speed up tow...
by Viking
Wed Jul 09, 2008 9:42 am
Forum: General Discussion
Topic: brighten 12v light (LED?) over 2 minutes; low voltage trigge
Replies: 15
Views: 7757

Hello Lyndon/Bryan, Yes, the linear/analog approach is the simplest, as you correctly point out, vision (at least human) is not linear. I suspect that you would need to have small steps at the beginning, gradually increasing towards the end, for a human to perceive this as a linear increase in brigh...
by Viking
Tue Jul 08, 2008 9:08 am
Forum: General Discussion
Topic: brighten 12v light (LED?) over 2 minutes; low voltage trigge
Replies: 15
Views: 7757

Hello Bryan, Had a look at the control board specs, and although it doesn't explicitly say so, it implies that there is a 'volts free' switch connected to J14. The annoying thing is it doesn't specifically say so, and I cannot see anything resembling a relay on that board. I thought the white rectan...
by Viking
Mon Jul 07, 2008 10:20 am
Forum: General Discussion
Topic: brighten 12v light (LED?) over 2 minutes; low voltage trigge
Replies: 15
Views: 7757

Hello Bryan, I should be able to design/build this for you, FOC. As I understand it, your 'PIC' board supplies a switched 12VDC supply, when the sensor is activated? Is this correct. Then you want a circuit operating on this switched supply to gradually bring on a 12V light. Please give specificatio...