Cutting Flex Strips

[smartcontrols]

I have spent the last week working with my SS Flex Strips. One thing I found (after frying many nodes) is that although it is marked to cut it every 3 nodes. With the way the circuitry is you can really only cut it every 15 nodes.  (About 20 inches).

You need to go by the factory joints. I was able to get a 9-node section to work; it has to be the last 9 nodes in the 15-node group. But it did not last very long. Anything other than that shorted out right away.

Just my findings so far. This is from many hours of real trial and error, I am not an electronics guy. Maybe one of them could look at the circuit and advise us more.

-Jeff
 

[odlids]

That does'nt sound good.

How are you cutting them? Scissors, side cutters?

Is the strip still connected to controller (TH2010 I presume) when you cut them? I ask this because the TH2010 will still have power on the OV and 12V lines when the on/off pushbutton is in Off mode. If you cut it powered up there is every chance you will destroy the TM1809, I don't imagine that the DO line will take kindly to being shorted to either ground or 12V whilst powered up.

How are you soldering/connecting the new pigtails?

Show us some pictures (if possible) and we will try and assist.

Cheers
Odlid Dave

[smartcontrols]

They are not connected; cut with seizers, new pig tales. It is very repeatable. I do not believe it is operator error. It very much looks like it is a 15 node circuit.

If you look at the strips.. Each of the 5 chips does run 3 nodes. But each of the 3 node sections is different. The last 3 node group has capacitors that the 2nd 3 node group does not have. The 1st 3 node group has resisters that the 4th no group does not have, ect.

[tng5737]

Looking at the strips more closely - it would appear to me that the "cut" pads are to be used to cut and join the two sections with a length of wire.   Presumably to enable one to go around say a corner or something - not to create new strings.   You could create new 'strings' by cutting where the sections are lapped and soldered which occurs just prior to R1 on the strip.

[odlids]

I have a couple of flex strips at home, I will have a look at them tonight and double check the layout but it sounds like you are right. Fortunately I will be using them as full lengths but could be a bummer for those wanting to cut them into short lengths for complicated display elements.

 Cheers
Odlid dave

[jeffcoast]

Would it be possible to cut in the middle of the 5 node section as long as it stayed connected to the rest of that section by soldering wires to it? This might put a damper on my plans if I am constrained that way. My roofline has a few areas that are only like a foot long where I will have to go 90 degrees and had planned on cutting up a few of the strips where needed. As long as I left the sections connected I wouldn't see how it would make a difference.

[tng5737]

It looks like you could do that at any of  the cut points - you just can't start a new string there

[odlids]

I don't see why that would'nt work, as long as the connecting wires are kept short (less than a metre). Experiment and see what works.

Cheers
Odlid Dave

[jeffcoast]

Good, then I can still do what I was planning. I don't think any section would be more than 6 inches away from the next.

[tng5737]

why not just buy the rectangles for your project

[jeffcoast]

I may end up with some, but thought I could get by with just strips for lining the roofline.

[CW]

I assumed you could cut on any of the cut lines and start the the next one on that cut line.  That is half right.  You can cut on any cut line to shorten, you have only 4 places to light up whats left.  As thg5737 said there are over-lapped splices, these are 3 places plus the original start = 4 places.  These are identefied on the front side by printed arrows as the start point.  This is where you need to soldier the wiring on.
I was able to salvage the first one I cut in the wrong place by soldiering back together.  I needed 4 strips of 21 leds per flex strip for the project I am working on.  I am making a fireworks break with 8 spokes. Each spoke will have the 21 flex strip on a pvc pole.

[tng5737]

I was checking my strips...  it appears that there are five "sections" to every "segment".  A segment being that area between the soldered joints on the strip.   Now each section is identical , EXCEPT the very beginning part.   There are three different types of these - Type I - starts with a resistor marked R1 labelled - 511.  Type II - two empty pads with a diode symbol marked between the pads.  Type III - a component labelled M4 (possibly a diode?).  The order of the sections in the segment is as follows - TYPE I....TYPE II...TYPE III...TYPE II...TYPE II     The question is WHAT are M4 and R1 used for?   It might be possible to add a compnent in front of each section to enable these to be used independently.  Perhaps, RJ or someone who has done an in depth analysis of these devices can shed more light on the topic.

[RJ]

Are you kidding?  I am learning by listening to you guys. I was told you could cut them so I thought everywhere thay had the pads could be cut. I have never cut any of mine yet.

RJ

[tng5737]

it is possible that you damaged the strips somehow they are kind of delicate