Skybuck Flying wrote:
Hello,

The following are the requirements for a piece or pieces of hardwa

A device which can stand on a table:

1. Dimensions: Approximately 20 centimeters width, 3 centimeters heigh,
2 or 3 centimeters thick.

2. The device should be capable of display text, about 20 to 30
characters. (Probably led display)

3. The text should be remotely controlled by for example a PC.

4. The device should have a network chip.

5. The device should be uniquely identified because multiple of these
devices are necessary.

6. Each device should be remotedly controlled by the same PC and it
should be possible to send different text to each device.

7. The device should be able to work for at least 20 hours straight on
for example battery power or other form of mobile power storage/accu.

8. The battery/accu should be replaceable and possibly chargeable,
should charge rapidly within 4 hours.

9. Some kind of second device/pci express card (?) is needed for the PC,
perhaps wifi, blue tooth or something else to controll all of these
table devices, perhaps 20, perhaps 30, something like that.

10. The device should look good/polished... no loose wires, it should
have a nice black package around it or perhaps other color... something
that looks decent/finished.

Recommendations ?

Bye,
Skybuck.

https://learn.adafruit.com/32x16-32x...atrix/powering

"Power

Although LEDs are very efficient light sources, get enough of
them in one place and the current really adds up.

A single 32x16 or 32x32 RGB matrix, running full tilt (all
pixels set white), can require nearly 4 Amps of current! Double
that figure for a 64x32 matrix.

On average though, displaying typical graphics and animation,
these panels will use less. A 2A supply is usually sufficient
for a single 32x16 or 32x32 panel, or 4A for a 64x32 panel.
There’s no harm in using a larger power supply rated for more
Amps (e.g. a 10A supply), but never use one with a higher Voltage
(use 5V, period)!
"

So while having a battery powered LED display sounds nice, 20 hours
with a load like that is going to require car battery sized
supply sources.

Also, be careful of getting a display which is too bright. A
local business attempts to burn out your eyeballs, with their
LED sign. The result is, no human can actually face their sign
square, and people have to look away. As a result, nobody
can see the "sale" items, or nice pricing. The person
running the sign, is an idiot.

When a billboard sized LED sign was installed next to a local fire
station, the staff could no longer sleep, due to the gigantic
flashing LED light levels. For a period of time, a compromise
was reached, where the billboard was turned down, to "human"
light levels. Eventually, the billboard advertising company
removed the sign, realizing it was just a stupid idea. The old
mechanical rotating billboard signs, while crude, are a lot more
effective. Using an "eye-blaster" near a highway, isn't all that
clever. If you interfere with highway safety, run afoul of local
bylaws, you could be in for a lot of visits from inspectors.

*******

Another possibility would be OLEDs. I quick check on Chinese pricing,
shows about $200 a linear foot. Monochromatic. Yellow is a nice
color.

*******

A $2.00 piece of white card plus a black marker pen, is a
cheap alternative, has good contrast, and is just as effective.

Paul