Re: Tech: MM Color Changing LEDs with PinLED WPC-95 driver board
- From: martin <martin.reynolds@xxxxxxxxx>
- Date: Sat, 31 May 2008 11:14:41 -0700 (PDT)
On May 31, 11:00 am, beaver <e...@xxxxxxxxxxxx> wrote:
LEDs act different than bulbs when off. A bulb when it is cold will
have a very low resistance. A small trickle of current will not light
them up. An LED however has a sharp 'knee' in its I-V curve. As a
result, before they conduct, LEDs tend to have a high impedance. A
small amount of leakage in the drive transistors is probably causing
this dim light.
You can prevent this by putting a resistor in parallel with the LED.
This shunts the leakage current around the LED. A value around a few
hundred ohms should work.
Edward Cheung CARGPB26
On May 31, 1:52 pm, "Jim Lindsay" <DIES...@xxxxxxxxxx> wrote:
These LEDs are also lighting up when the lights one to the right and
one left of them in the lamp matrix light up. This MM also has the PinLED
WPC-95 driver board. This happens in game play and single lamp test. Is
there a way to make these light up only when they should? They are a very
nice feature but they screw with your game play when they come on at the
wrong times. When I install the normal bulbs the game works properly. I have
tried these LED in other positions and the same thing happens. Has anyone
else seen this or know of a fix?
Medieval Madness Color Changing LEDs (Set/2)http://bayareaamusements.com/Merchant2/merchant.mvc?Screen=PROD&Produ...
I inquired at Bay Area Amusements and received the reply:
Don't know why that would be happening unless some diodes are not
connected where they are supposed to be in the circuit, etc. The driver
board is electrically the same, and we've not heard from anyone else about
any phantom lighting. You can return the color changing kit if you wish.
Jim- Hide quoted text -
- Show quoted text -
I am not sure it is that simple. Leaky drivers should affect a whole
row or column.
I suspect that Williams used a make-before-break algorithm on the
lamps, so there is a brief period where the signals overlamp.
Invisible on a regular lamp, but a sensitive LED gets enough energy to
glow.
Example:
How I think that it is, and how I would do it for incandescent lights
Row 3 Column 3 Column 4
off on off R3 C3 is off for
10msecs
on on off R3 turns on before C3
transitions to C4
on off on R3 C4 is on for 10
msecs
And how I would do it for LEDs.
Row 3 Column 3 Column 4
off on off R3 C3 is off for
10msecs
off on off Clear all rows
off on off C3 transitions to C4
on off on R3 C4 is on for 10
msecs
So a small change to the code is needed...
We should get this scoped to prove it out.
.
- References:
- Tech: MM Color Changing LEDs with PinLED WPC-95 driver board
- From: Jim Lindsay
- Re: Tech: MM Color Changing LEDs with PinLED WPC-95 driver board
- From: beaver
- Tech: MM Color Changing LEDs with PinLED WPC-95 driver board
- Prev by Date: Re: Would you spend $1500+ for an EM game?
- Next by Date: Re: Would you spend $1500+ for an EM game?
- Previous by thread: Re: Tech: MM Color Changing LEDs with PinLED WPC-95 driver board
- Next by thread: Re: Tech: MM Color Changing LEDs with PinLED WPC-95 driver board
- Index(es):
Relevant Pages
|
