Cutting Flex Strips

[IndianaChristmas]

I thought I would become more "edumicated" about cutting strips before I started doing it!  Went to the WIKI and looked at the video on cutting smart strings. 

My strings and I suppose many of the newer ones, are different than those shown in the video. 
1. Where the diodes were noted, I now have very small surface mounted object in its place.  This is labeled "R1".
2. There is no solder point for the locations, not on the meter mark. 

Is it safe to assume that the necessary jumper at the missing diode locations is no longer needed?  If not, where would this jumper be placed?
If no jumper needed... I ask the following to be certain this is still possible... I can cut the strip into 3 LED sections?

Thanks.

[thestig]

Great question, I need to know the answer to this too.

[rm357]

Since we don't know what you have, it might help if you posted some pics...

[zwiller]

You are correct, the newer strips do not have the diode and do not need the jumper and they can be cut every 3 led's HOWEVER a section of flex strip must always START at the one meter point.  On my strips at this location there is a solder joint and the "R1" resistor you mention.  Pic attached.  (yes I tried starting a new section without the 1 meter start and it just doesn't work)  That said, you can CONTINUE a section without starting at the 1 meter location.  IE cutting strip for a 90 degree joint for window frames, etc.  I did extensive cutting and jointing of flex strips last year... 

[IndianaChristmas]

Sorry I wasn't clear on the I was using (it was late, I was tired and used strips and strings in the same post).  But as zwiller guessed I'm talking about strips.

If I understand correctly about cutting strips...

I could only have a 3 LED section if it started at the solder joint?

If I spliced two segments together (say 2 x 3 LED segments), I would be OK however?  (that seems to make sense)


Thanks.

[rm357]

I assumed you were talking about strips, but if the design/layout has changed, it helps to be able to see what you are talking about.

Without being able to see the changes to the strip design, there is no way to advise you.

It's kind of like saying I have a car, what is the part number for the replacement brake pads.
Without knowing the make, model, and year of the car, any answer is a shot in the dark...

[zwiller]

Yes, if you want a single section of 3 leds controlled by a SSC you must use the solder joint.  You could add another 3 led section or more but the first (and connected to SSC) must be the solder joint. 

Learned something new!  The current flex strip in the wiki consists of 8 - 1/2 meter sections soldered together.  Previously I thought there were (4) 1 meter sections...  Anyway, each 1/2 meter section is comprised of (5) smaller 3 led sections with their own circuit however only the first 3 led section only contains R1 (current limiting resistor?).  Whatever it may be it is clear it is essential to the entire 1/2 meter strip and must start the circuit...  I don't really think it's that big of deal as long as you plan/prepare for it. 

Not sure that it matters but the rectangular module is IDENTICAL to a 3 led section of flex strip so if you are designing something intricate the rectangular module is far superior choice but offers the same spacing...

Hope this helps and if you still have questions ask away!   

[drlucas]

I have a similar/unrelated question - almost worth a new thread for. Connecting the flexstrips. Is it best to just solder the new joints together strip to strip like the "factory" joints have, or do you use some 3 RGB wire to join them together (especially on the 90 degree turns)? Also, when cutting the strip, do you just use an exacto knife, make a tiny slot in the plastic, solder and then use up the silicon tube to seal it again? I'm either making two windows or two vertical lines to trace the garage with the extra 30 LEDs that I have from my megatree left over.....have 12 strips extra so need to carefully plan how I can put these strips to valuable use.

[zwiller]

Not sure what you mean about connecting to SSC but all my strips have the 3 conductor cables spliced/soldered to the wires connected to the strip and then the SSC is wired as usual with the corresponding 3 conductor to attach to strip.

I used a section of 3 wire for my 90 degree turns.  I used an exacto to cut the silicone cover and used clothespins to retract the cover so I could neatly use a sharp pair of scissors to cut the strip.  That said, I just desoldered the factory joint when I was working on that joint area.  (using exacto and clothespins on cover)  In my flexstrip packages were various parts for jointing, ending, and sealing the cover.  On my 90's I used the end caps with the holes.  I got the 3 wire soldered on 1 side and slid both end caps over the wires.  After soldering the opposite side and checking that it worked I used the silicone sealant from the kit.  I put pressure on the sides of the cover creating a round opening and put a substantial amount of sealant inside then worked the end cap down squeezing gently to ensure it was filled/waterproof much like the factory did.  I used a bit of tape to keep the cap from moving.  I was fortunate that all my strips were mounted to wood frames which allowed me to mount the strip in place while the silicone cured. 

Some pics of my window frames etc are at reply 21: You are not allowed to view links. Register or Login

This all sounds more complicated than it really is…  Just remember to start with a factory joint as above. 

[Steve Gase]

I've seen people use wires to connect the SSC and the pieces, with liquid electrical tape to cover the solder points.  I've also seen people use shrink tube.

[drlucas]

my bad...meant flexstrips. PBC (post before coffee) issue. sorry. your post answers my question 100% clearly. thanks for the tip on the clothespins

Not sure what you mean about connecting to SSC but all my strips have the 3 conductor cables spliced/soldered to the wires connected to the strip and then the SSC is wired as usual with the corresponding 3 conductor to attach to strip.

I used a section of 3 wire for my 90 degree turns.  I used an exacto to cut the silicone cover and used clothespins to retract the cover so I could neatly use a sharp pair of scissors to cut the strip.  That said, I just desoldered the factory joint when I was working on that joint area.  (using exacto and clothespins on cover)  In my flexstrip packages were various parts for jointing, ending, and sealing the cover.  On my 90's I used the end caps with the holes.  I got the 3 wire soldered on 1 side and slid both end caps over the wires.  After soldering the opposite side and checking that it worked I used the silicone sealant from the kit.  I put pressure on the sides of the cover creating a round opening and put a substantial amount of sealant inside then worked the end cap down squeezing gently to ensure it was filled/waterproof much like the factory did.  I used a bit of tape to keep the cap from moving.  I was fortunate that all my strips were mounted to wood frames which allowed me to mount the strip in place while the silicone cured. 

Some pics of my window frames etc are at reply 21: You are not allowed to view links. Register or Login

This all sounds more complicated than it really is…  Just remember to start with a factory joint as above.

[drlucas]

 

I tried to desolder the two strips from each other and made a big mess....tonight i'm going to try to cut away as much of the excess strip I can and just solder a third  one over top of the existing two and see if that is any cleaner. I even pulled out my desolder braid and I can't get it the two strips separated nicely, so time for another approach.

[jnealand]

Makes me wonder if you were truly on a soldered joint.  They come apart very easily, at least mine did.  Where you do not see the solder crossing the joint I believe you just cut them.  I've only separated them at the solder joints where you can clearly see solder flowing across the joint.  I then soldered on 3 pin connectors and that was also pretty easy except for holding them still.  I put the strips on a piece of 1x2 and then wrapped velcro around each end to hold the strips from slinking around on me.  The same tip works when soldering the 3 pin connector to the wires that come on the strip.

[zwiller]

+1  Mine came apart real easy too.  Maybe try some flux. 

Not sure what you mean about "going to try to cut away as much of the excess strip I can and just solder a third one over top of the existing two and see if that is any cleaner" but it sounds like disaster.  Post a pic or more info and maybe we can figure it out.  Have your coffee yet?   

[jnealand]

Here is my simplistic soldering desoldering jig.