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Topic: "Rainbow" LEDs (Read 1 time) previous topic - next topic

Alex D

Has anyone ever used the "rainbow" leds? They only have 2 leads but some vendors are claiming they can output 7 different colors. It's hard to understand the foreigner's description of their item but they are saying it changes color based on input voltage. Is this someone anyone has come across before or is this a poor description / scam?

Alex D

Here's a sample of what I've seen on eBay... Any advice?

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110396023112&ru=http%3A%2F%2Fshop.ebay.com%3A80%2F%3F_from%3DR40%26_trksid%3Dp3907.m38.l1313%26_nkw%3D110396023112%26_sacat%3DSee-All-Categories%26_fvi%3D1&_rdc=1


Ran Talbott

It's probably a poor description of modules that have three LEDs and a small chip that sequences them inside the plastic blob.  They appears in decorative things like jewelry,  and other gadgets (I have a pen with one that illuminates the transparent barrel).

But it's also possible that the chip built into the blob is one based on comparators,  rather than timers,  and really does turn different LEDs on based on the applied voltage.

I'd say the odds are at least 5-to-1 in favor of the first description,  but the only way to be certain is to make the $13 bet,  and try them when they arrive.

Ran

Rusty in Texas

Read the replies to the questions posed on the eBay page.
Indeed, these "rainbow" LEDs simply have a chip in them to
slowly change colors at a given rate and not upon the voltage
applied to them.

Grumpy_Mike

Quote
there's no way there are any chips in it or multiple LEDs


No you are wrong, there have been flashing LEDs with chips in them for many years and this technology is very similar. The chip is very small. It doesn't need to be very big at all.

Alex D

Oops! Thanks for noticing that, I didn't see the FAQ page at the bottom. So there's no way to control them, they just flash on their own.

Rusty in Texas

Correct, they flash by themselves when power is applied.
You can get slow or fast flashing models.  I prefer the slow
flashing LEDs for the toys they go into.

Mike Mc

Where is that quote from Mike?

Did someone do a crafty edit?

Grumpy_Mike

Quote
Did someone do a crafty edit?


Yes I think they removed the post altogether. They said that they thought the colour might be controlled through different voltage levels but not auto changing because there was no sign of any chips in the advert that they could see. They also said that it might be possible to include such chips some day but not today especially at this price today.

Fortunately I have an embarrassment saving bad memory for names.  ::)

Ron C

RadioShack sells a seven color LED with 3 wires. The 3rd wire lets you select the "mode"
for predefined patterns...

FW supply (V)(typical): 3.2V
Peak current (1/24 duty cycle, typical) 35mA
Capable of single or mixed color lighting and blinking
Auto-start one-shot slow light up and fade, then blink
On/Off key color change control: R,G,B,RG,GB,RB,RGB
RoSH compliant

http://www.radioshack.com/product/index.jsp?productId=3060680&tab=features

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