LPD6803 vs TM1809

[jrock64]

Trying to decide between the LPD6803 vs TM1809
Comparing features of these two chips in RGB strip format.

They both cost about $60 for 5 meters
They both have 10 control chips per meter
They both have 30 5050 RGB LEDs per meter.
They both have a 3led roughly 4in cut length.
They both are 12volt and need .6Amp per meter.
They are both supported by the E68x controllers.

The differences.
The 6803 is constant current, and the 1809 is constant voltage.
Constant voltage my be bad for a single LED but in groups of 3LEDs is it any worse than dumb 12v strip.

The other difference is the 6803 is 5 bit and the 1809 is 8 bit.
So while the 1809 supports all 256 levels, the 6803 only supports 32 distinct levels.
That means that levels 1 thru 7 are not recognized, and only levels 8, 16, 24, 32, 40.... are recognized.

Are any of my facts or assumptions wrong?
else I may be leaning toward the 1809 based strip.

Joel

[budude]

Unless your 1809 strips are different from mine, they are only cuttable at the 1/2 meter points. There are what appear to be cut points at every 10 cm point but that is not the case. Cutting there breaks a trace or two that travels between. There is a fix but you have to run a wire around to get them working again - erm213 found out about this. I left mine at .5m sections and just hid the excess (which was 6 pixels) and used the E681 to ignore them. Other versions/vendors of the strips may allow smaller cuts. Other than that, I really liked my 1809's!

[erm213]

Ray is working on a 1809 version that is able to be cut every 3 LEDs as promised. Stay tuned!

Erik

[jrock64]

Unless your 1809 strips are different from mine, they are only cuttable at the 1/2 meter points.

Good to know.
Looks like the Blooming Rose III will have 1m long spokes

Joel

[djulien]

Ray is working on a 1809 version that is able to be cut every 3 LEDs as promised. Stay tuned!

Would that end up being a different part#, or what would be an easy way to know based on the description?

don

[jrock64]

Just to add to the confusion

http://www.aliexpress.com/product-fm...olesalers.html

5m led digital strip,DC12V input,WS2801IC(256 scale);12pcs IC and 36pcs 5050 SMD RGB each meter;without controller;IP65

Looks like the best of both and then some.


Joel

[Barnabybear]

I thought the 2801 was normaly asociated with 5 volt strings?
I know it can be used on 12 volts but its a lot of work.

http://www.sparkfun.com/datasheets/C...LED/WS2801.pdf
Pages 8 & 10 for the mods.

Are they realy putting that in each node or is it controled in sections or has the web site got the voltage wrong?

[jrock64]

12pcs IC and 36pcs 5050 SMD RGB each meter

Well now I am just confused and a little concerned.

So they need a diode, a resistor and a cap to convert to power that the chip can use... and
3 sets of transistors and resistors to drive the 3 LEDs with constant voltage, not current.

Maybe that explains where there of no close ups of the strip on the site.
Might be a good idea if they got it to work.

Has anybody got there hands on any of this strip???
David, you out there???

Joel

[jstjohnz]

Normally 12 volt pixels run multiple leds in series. The current draw is the same as a single LED and shouldn't require an external transistor.

[jstjohnz]

FWIW, the next firmware version of the E680/E681 will support 7-bit dimming (128 levels) for the 6803 pixels.