Say I have 5 PS1 screens, just out the box. Is it possible to connect all the screens to display the same images from a single source, such as a laptop or DVD player. Also, I wouldn't want to have 5 seperate power adaptors plugged in. How would I go about achiving this so that that all the power comes along a wire to each from a single source.
A VGA or Composite video repeater hub probably. You could built your own powersupply to feed them all at once. To make it easier, send one to Smilodon, and another one to me, that'll only leave you 3 to mess with
VGA Repeater Hub. Cheers, I figured that's what I'd need for the signal. TBH it was more the power side of things I was worrying about. Anyone able to offer any help on that?
Each screen requires DC7.5V which is normally supplied by a Mains AC Adaptor. Each screen draws 6.8W.
that's about 1 amp @ 7,5 volts.. (aprox.) that will be 5 amps... the most difficult part is that voltage... you could out in a regulator circuit, but making it handle 5 amps could be hard... and then run this of the PSU in you'r comp. the second option is to get a seperate psu that can handle all that current. this could get expensive.... connecting all those smaller PSU's (supplied with the screens) isn't recomended though... that have to have the EXACT same voltage to allow you to do that...
Two suggestions: 1) A working, but not the best solution: A dead easy way of powering all 5 screens from one power source would be to use 5 x LM7808 8Volt regulators to supply the screens. All 8 of these regulators could be supplied from the same +12V supply, hence only one power cable from the supply. It is unlikley that the extra 0.5V will cause any harm; the original power supply was probably not regulated anyway. This supply would probably need to be taken from the PC; alternativley, you could obtain an 8+ amp 12Volt mains transformer, but this would probably be rather pricey. Another point: it is unlikley that the screens actually draw 1Amp. Cut into the power cable of one of the screens, and put an ammeter on it. (on the low voltage side!!), connect it to the screen, and switch it on to measure the real current being drawn. I reckon it will be significantly less than 1Amp. If it is less than 0.5 Amps, you would only need three regulators, rather than 5. (run two screens from each regulator) The LM7808 regulators only require two small capacitors each to run, so the circuit would be relativley cheap to make. (under a tenner) 2) A very good, possibly the best solution: Probably the best solution is to go for something like the MC33167T 5Amp adjustable regulator, which would be able to supply all 5 screens at once from a 12V DC supply. This is a switching regulator, so it is more efficient than the previous solution. (makes less head) Also, the circuit will be smaller and simpler still than the one suggested above. This is the solution I would go for if I were to make a power supply to drive all 5 screens. Also, the voltage would be exactly right, and the chip has short circuit protection - if something goes wrong, it will switch off to prevent damage to your screens or your PSU. Both these chips are available from farnells. Just type the chip number into their search box and they'll supply you with the datasheets for the ICs telling you how to use them. If you cannot find them, I'll put links up for you. Edit: alternativley, you could give up and sell me all the screens; I ordered from Ebuyer a fortnight ago and haven't heard anthing.
isn't the 7.5 an "optimum" voltage? IE: it will operate anywhere between 7 and 8? So, in reality, couldn't he use 7v (12+5+)? Like it says in the sig \/
Thanks for the replies. These 5 screens are going to be for business use. As it happens they're going to be mounted on a wall with about 2 metres gap between each. I don't plan on running them off the computer PSU - I'm not even sure at the moment if a PC is definitely going to be the source component. A DVD player or TV tuner might very well become the source. I'm liking the sound of the second idea. Are there any circuit diagrams of this type online that you could link me to?
Hi again, If you want to know more about the second solution I suggested, see the datasheet from farnell: http://www.farnell.com/datasheets/28561.pdf Unlike many datasheets, it actually provides practical examples for you to work with; the schematic and even a PCB for the circuit you will need is povided on page 10. From page 7, it tells you that the output voltage is going to be... Vout = 5.05 * ((R2/R1)+1) Therefore for 7.5Volt operation, R1 will need to be 14k ohms. (if my maths is correct; check for youself!!) Component layout for this type of converter is critical; you should be fine as long as you stick to the PCB design provided. One good thing about this type of regulator circuit is that it can be supplied with any DC voltage from 12V to 40V, so you have a wide range of possible power supply options. Personally, even if you're not going to be using a PC, I still recommend a PC power supply, since they are very cheap and reliable for the amount of power provided. Before constructing this (or any other) circuit, I do recommend trying to run these displays at 7V as suggested by Ubermich; if they do work at this voltage, you can simply use a PC power supply to do all the work, making your job dead easy.
Yeah, I could, but I think that'll be a bit messy - having 5 seperate plugs plugged-in. I'm happy with the regulator circuit mentioned earlier. Thanks very much, Bodger.
