Cutting TM1809 RGB Strip

[jklingert]

So I a looking at the TM1809 strip that I got from diyledexpress and I have a few questions for folks who have already used it. While it appears to be cuttable every 10cm, the various sections are different. Starting at the input side and counting down the strip, it is obvious that the 1st and the 5th led/IC cluster have an additional 330 Ohm resistor that the 2nd,3rd and 4th clusters do not. It also appears that the strip has solder joints after every 5th segment where they join the pcbs together.
1) Is this really cuttable and usable every 10cm or 50cm?
2) Do you have start off each lengths of lights with a cluster 1 and a end with a cluster 5?
3) What role do the two 330 ohm resistors play on the design?
4) What is the solution if you want to use them in length other them multiples of 0.5M?

Thanks,
Jack

1st Cluster
section1.jpg

2nd-4th Cluster
section2.jpg

5th Cluster
section5.jpg

[David_AVD]

The 330R resistors are probably there to dampen the data line at the start and end of every strip. They are not really needed between 50cm segments, but they don't hurt and it's more bother to remove them when assembling the 5 metre strips.

So, my guess would be cuttable every 10cm. There's one way to find out you know!

[budude]

If your strips are like mine, they cannot be cut < .5m (where the cut joints are soldered together) without adding a 'fix'. It consists of running a wire from the end (I think +DC) back to one of the resistors. erm213 figured out the issue and contacted Ray for more info. He has a picture of how to fix it so you may want to ping him. Luckily my setup worked out where I could stick with the .5m lengths and using 'dark pixels' in my E681 config.

[fasteddy]

Doesnt seem to be a very good choice of strip based on these requirements and should be avoided unless you are happy with 1/2 metres cuttable sections. I think there are better choices out there if you want individual LED control like the 2801 32IC per metre strip

[budude]

Yeah - but ouch! - $99.08 for 5m shipped - I think I paid around $57 for my 1809s... (to be a bit fair mine are only 30/m LEDs) I agree with your logic but the fix wasn't that bad really - just a single wire back about 2 inches or so as I recall.

[fasteddy]

One of the other issues ive heard with this strip when ordered from Ray Wu is the channel ordering can be incorrect so instead of going sequential from pixel 1 it instead has each 1/2 metre section with reversed channels which can create a lot more work to setup in your software.

[budude]

Hmm - I didn't have that problem - they are BRG order but that's easy enough to fix (made changes in E681). Personally I like the strips a lot - they look great and run on 12v so they stay pretty even colored.

[tjetzer]

first, Brian's strip and Jack's strip are from different suppliers. Just because Brian's strip needed a fix does not mean Jack's will nor does it mean the same fix will work.

The specs I have state the strip can be cut every 10cm. Although it is very possible that information isn't completely accurate.

Jack, I have a 5m strip here that I will use to experiment on tomorrow night. I will follow up then.

[dpitts]

What Eddy was talking about is this. The strips that are referenced in the wiki on DLA cannot be cut every 10cm. They can be only cut every .5M. There are three threads that outline this on DLA.

http://diylightanimation.com/index.php?topic=6020.0
http://diylightanimation.com/index.php?topic=5161.0
http://diylightanimation.com/index.p...8613#msg118613


Because of this I contacted Ray and asked him to provide strips that can be cut every section. he sent me ten 5M strips of TM1809 from another manufacturer. These strips had data that was ordered incorrectly. Data 1 went to Led3 and Data 3 went to LED 1. So output of data was like this 321,654,987.. and so on. I let Ray know about this problem and he sent some other strips. Ray was awesome and quick to make things more than right, he has my future business because of his integrity. The strips he sent were TM1812 strips where each chip controllers 4 leds. These are able to be cut every 4 leds and they work great.

They come in 4M and 5M.
4M TM1812 strip
5M TM1812 strip

One of the other issues ive heard with this strip when ordered from Ray Wu is the channel ordering can be incorrect so instead of going sequential from pixel 1 it instead has each 1/2 metre section with reversed channels which can create a lot more work to setup in your software.

[tjetzer]

As promised, I have run a few tests on the DIY LED Express pixel strips.

For my test I used half a meter of 1809 strips. I first cut off a 3 pixel section and connected it to an E681. This 3 pixel section functioned flawlessly. I then connected the remaining 12 pixels to another cluster. This section of pixels also functioned flawlessly.

These pixel strips are cuttable every 3 LEDs.