Search found 87 matches

by Viking
Wed Aug 13, 2008 11:38 pm
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 40724

Hello Federico, Whether it is the simple or complex version, the format of the hardware would be almost, if not identical. The only change is in what form the data is sent. In fact it doesn’t matter in what order you send the data for a particular panel , just so long as you know which pixel to co...
by Viking
Wed Aug 13, 2008 4:11 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 40724

Hello Federico Irrespective of the form the PIC receiver takes, it will always count the ‘start bits’, This is the first ‘space’ after the last ‘stop’ character. There is no ‘special’ bytes sent. The ‘mark between packet’ is there mainly to allow the system to do some data proces...
by Viking
Tue Aug 12, 2008 4:11 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 40724

Hello Federico, There are two ways of configuring the PIC within each receiver. The simple way:- The only setting that the code needs, is which panel it is in. This is because all panels are 200 pixels or 25 x 8 bit words. So panel 1 is always 1-25 bytes… panel 28 is always bytes 676-700 and so on...
by Viking
Mon Aug 11, 2008 9:54 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 40724

Hello Federico, Hope you had a good weekend away. I won't throw any more mud in the water, but I've come to the conclusion that Dyarkers idea of making all 28 panels identical is the best one, despite the extra cost in terms of hardware which would not be used in all panels. This would mean that all...
by Viking
Sun Aug 10, 2008 8:25 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 40724

Hello Dyarker, yes, you are right, I tend to get carried away sometimes. Must be all that caffeine?
Will wait for Federico to read through and digest.
Regards
Rob
by Viking
Sun Aug 10, 2008 6:34 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 40724

OK, hopefully got this one right. BUT display is still 70x80, as all panels circuits are identical and have 200 pixels of data sent to them. The actual display area is 70 by 70. And the data to each panel must be sent in reverse, as the first bit of data to be clocked into the shift register ends up...
by Viking
Sun Aug 10, 2008 5:08 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 40724

Yes, definitely losing it now! Just counted pixels again and realised that the top and bottom rows have 15, but the other are 20!!
Muppet!
Take an hour to lie down in dark room, then start again!
Rob
by Viking
Sun Aug 10, 2008 5:04 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 40724

Hello all, maybe I lost the thread somewhere along the way, but the panels were always 20x10 pixels? and arranged as shown, with four rows of 7. But in Federico's original drawing, if you count the pixels in a panel, there are only 15 by 10. So the square is a true square (actually it is 60 by 70 pi...
by Viking
Sun Aug 10, 2008 1:57 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 40724

Hello Federico/Dyarker, I'm having difficulty mapping the pixels on the current version of the display because it is not totally square. You get an oval unless you let the circle not come up quite to the top and bottom edge. For a 28' by 28' square using 28 panels, each panel is actually 4' by 7' an...
by Viking
Sat Aug 09, 2008 10:21 pm
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 40724

Hello Dyarker, I've just realised that in the original drawing for the display, the panels are 15x10 (150 pixels) and not 20x10 (200 pixels) as I had originally thought! Not sure now how I thought it was 200 pixels. So I will revamp the drawings I posted above. I'm also going to invert the layout of...
by Viking
Sat Aug 09, 2008 4:06 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 40724

Panel Layout:- (Original drawing removed) Display Layout:- (Original drawing removed) Data is written to all 200 locations on each panel irrespective if whether there is a pixel there or not. This makes the receiver easier to design, and means all 28 receiver chips are identical. More to follow on w...
by Viking
Fri Aug 08, 2008 9:50 pm
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 40724

Hello Dyarker,
Give me a day or two to pull all the design together in one package. So much has changed, then changed again, that I probably the one on who has the full picture now! So I will put together a full and detailed spec on this.
Regards
Rob
by Viking
Fri Aug 08, 2008 9:26 am
Forum: General Discussion
Topic: Need help identifying a semiconductor
Replies: 23
Views: 6804

Probably devices, most likely first:- 2SC316 - Silicon, NPN, 30mA Ic, 300mW Ptot - package TO18, EBC starting from tab. 2N316 - Germanium, PNP, 500mA IC, 150mW Ptot - package TO5, EBC starting from tab. 2SA316 - Germanium PNP, 20mA Ic, 60mW Ptot, package TO5, EBC starting from tab. BF316 - Silicon P...
by Viking
Fri Aug 08, 2008 8:00 am
Forum: General Discussion
Topic: Need help identifying a semiconductor
Replies: 23
Views: 6804

Well, the 7939 is almost certainly a date code, 39th week of 1979. Does this fit with the age of the equipment?
You say TO92, are we to assume that the device has three leads?
If so then probably a transistor or thyristor or some such device.
Will have a look through the possibilities.
Regards
Rob
by Viking
Thu Aug 07, 2008 9:49 am
Forum: General Discussion
Topic: Resistor Bank IC
Replies: 5
Views: 1253

This is usually called a resistor network and is made by all the major resistor manufacturers, just Google 'resistor network'.

Image

Regards
Rob