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| History of Addressable LEDs |
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| Scottie:
--- Quote from: mikeselectricstuff on December 09, 2021, 01:48:17 pm ---The Color flex and other proucts use a chip which Color Kinetics developed called "Chromasic". Similar to WS2812 but actually done properly - more colour depth, nicer protocol. Many years ago I reversed the protocol, as their PSU/drivers were expensive and mechanically ugly. --- End quote --- That is so interesting, in the product brief they mention the control die being the size of a pinhead. Its too bad they never were able to package the IC and LEDs into a single leadframe like the WS2812. The WS2811 is just the driver IC in a 8-pin package similar to the Chromasic. I don't remember the actual value but I recall WS2812 starting to brownout at over 4.5V, meaning the constant current driver had limited compliance voltage. Worldsemi now advertise the WS2812-V5: --- Quote ---4).Ensure color consistency even under 3.5V working voltage. --- End quote --- Which would be similar to the Chromatic's rating: --- Quote ---LED DRIVER DROPOUT VOLTAGE 0.55V, typical at 125˚C --- End quote --- In some of the color kinetics press article I see them targeting many deep pocket applications such as pools, spas, and architectural lighting. I can only image what their products would have cost at that time. |
| Scottie:
--- Quote from: Ice-Tea on December 09, 2021, 03:42:28 pm ---At some point in the historyof addressable LEDs I think this has a place: https://www.barco.com/en/News/Press-releases/u2-vertigo-tour-a-feast-for-the-eyes-with-revolutionary-barco-technology.aspx --- End quote --- That is a great find, a real life light-curtain :). The datasheet for the MiSPHERE bulbs is available too: https://www.barco.com/services/website/en/TdeFiles/Download?FileNumber=R5976941&TdeType=1&Revision=01&ShowDownloadPage=False Look at the 12(ish?)-pin circular connectors on each of the MiSPHERE bulbs. I can only imagine what the cables and connectors alone would have cost... You even get branded rolling flight cases, too awesome! |
| mikeselectricstuff:
--- Quote ---They also employed pulse width coded signaling, and reference 1/4 and 3/4 of a bit times for high/low states: --- Quote ---In another embodiment, a given lighting system 102 may receive data coded with a code, wherein pulses of less than ½ of a pulse period correspond to a first logical state, while pulses of more than ½ of a pulse period correspond to a second logical state. --- End quote --- --- End quote --- From memory I think they either measure the width of the first pulse and reference this for the rest of the packet, or look at the change in puse width, either way it means it will work over a fairly wide range of bit rates. TI's 1-wire protocol which they use on the TLC5973 does something similar. |
| mikeselectricstuff:
--- Quote from: themadhippy on December 09, 2021, 02:33:56 pm ---What surprised me most is Color Kinetics didnt try and sue the inventors of other addressable leds --- End quote --- Especially as at one time they were notorious for suing companies due to their patent for using PWM to dim RGB LEDs, and pissed off the whole industry. I don't know if their attitude changed when they got bought by Philips, but it's now so established as standard practice that there's no way they could keep on top of it now. |
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