DiyLightAnimation
Hardware => Lynx Smart String => Topic started by: smartcontrols on May 02, 2011,
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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
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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
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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.
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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.
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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
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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.
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It looks like you could do that at any of the cut points - you just can't start a new string there
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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
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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.
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why not just buy the rectangles for your project
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I may end up with some, but thought I could get by with just strips for lining the roofline.
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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.
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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.
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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
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it is possible that you damaged the strips somehow they are kind of delicate
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I contacted Ray requesting that he find out just where we can cut these strips. This is his reply:
"i checked the engineer, he told me you can cut this TM1809 digital strip each 3 5050 SMD.
but you need to add a diode which can lead to short circuit beside the resistance(6.8K),please check the PCB, and find the location of the 6.8K resistance, and then add the diode."
I have asked for clarification sending him this photo - the arrows point to where I THINK he is talking about. When I hear back I will post the response.
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I am NOT going to start panicking, I am NOT going to start panicking, I am NOT going to start panicikng!!! If I just want to use the first 90 nodes, Could I just leave my strips whole and NOT have to add a diode? Ugggghh
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As long as the strip are "whole" they will work just fine - the problem comes when you try to cut them and run the 'cut' sections as if they were whole strings. I think most of us assumed that we could just cut these strings anywhere the two IN/OUT pads occur. Apparently, that is not the case!
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Admittedly, I don't have any strings yet, so no first hand experience, but I don't see how a diode is going to do much in a DC system beyond offering reverse polarity protection. When you mention 'frying', it sounds like an over current situation? Maybe the LEDs came on very bright for a second or two then died? Or possibly the LED's were normal and the chip died? If I read the datasheet right, the 1809 is actually a 5V chip which needs external resistance (7K) to run on 12V.
In either case, it sounds more like a current limiting resistor would be the fix? Is it possible there are 1, 2, or more resistors along the strip to help limit / balance current and you happened to cut a section out which had no resistor of it's own?
Datasheet
http://diylightanimation.com/index.php?action=dlattach;topic=4840.0;attach=5570 (http://TM1809 datasheet)
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If youlook at ther datasheet you will see a table which indicates that to drop the voltage from 12v to 5v you need a 7K resistor. That is the 6800 (682) resistor I believe he is talking about. It is marked RS. I also do not see what good a diode would do unless it is protect against accidental reversal of voltage. Ray has replied that he will get back with me soon.
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I am going to look at this myself as I can not understand why you can not cut it every place marked. The Diode I would also thing would be reverse polaritity protection. I was originally told you could cut them each place.
RJ
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Right on Ray's site for this item (http://www.aliexpress.com/product-fm/425556741-4m-waterproof-LED-digital-strip-by-tube-DC12V-input-without-controller-10pcs-TM1809IC-m-30pcs-5050-wholesalers.html) IT even says that you can cut these every 3 LEDs. I'd try this myself but at $53/strip - I don't want to find out the hard way that Ray posted bad info!
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Truth in advertising. It sounds like they can be cut at each pad, though they still need to be connected back to the proper section of the string!
Guess I'd be curious to know: 1) does each chip appear to have it's own Rs / 682 resistor? 2) If the voltage on the + / - pads changes as you go down the string or is there 12V at each pad? That should be pretty easy to check without damaging anything and what ever is coming out of the first section is going into the second section, so if there is a drop, then you would need to add the correct resistor or drop voltage on the 'input' of the later sections.
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has anybody tested them yet? is each led controllable, or just a set of three operate as one. when i test the metal squares, or the plastic rectangles, they operate as sets of three.
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Chris Modules are suppost to work all as one. They are a single pixel with multiple leds on them for brightness.
The Ribbons, ridged strip, strings all work with each led being a nodes so they work totally independant. I can control each led in the ribbons, ridged strips and strings.
RJ
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I heard back from Ray - he said that his engineer verified that the above photo is correct. The two empty pads are where you are supposed to add the diode. He did not specify WHY!!! Personally, I believe that as RJ said, it is to proptect against polarity reversal. In other words - the cut strings should not have burned out.
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Maybe they are not burnt out? Maybe they are not getting power?
Heres my thought,
I tried to look at the flexible pcb on them and trace it but it is really hard to do.
But if you look at the wiring diagram here :
http://www.aliexpress.com/fm-store/701799/209843764-349766591/5m-waterproof-LED-digital-strip-by-tube-DC12V-input-with-controller-10pcs-TM1809IC-m-30pcs-5050.html
Roll down the page to find a schematic of it inside a picture of the string.
It appears you should be able to cut it anywhere marked giving you a three led segment.
I am thinking ... (this is always dangerous!)
Maybe the power from each section does not connect to the power pads but bypasses them to the inside section of the diode pad. So you do not need a diode at each section because it would have a voltage drop and across a full string you would not want it as it would not work. You would only want one diode on the whole string to protect from hooking the string up backwards.
You can handle one voltage drop but not one for every 3 leds!
So to get power to the section with out a diode you need a diode added to pass the power. With out it you have no power applied. So a test would be to take one of the sections you think you killed and solder a jumper across the diode pads. Make sure to hook the power up the correct direction as you have no protection.
this is what the engineer means by "It might burn up with out it." He means it could be hooked up backwards on the power and be damaged with out a diode to protect it I am thinking.
My issue is my strips need to be cut in the middle for what I am doing and this is at a spot with a diode I believe.
Let me know what you find out as I will be very interested myself.
RJ
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Someone should try measuring the resistance from either diode pad to +12 and to GND. This may give a hint to whether it is a series diode (for reverse polarity protection) or a zener (for better regulation of the 5V rail). Do the diodes have any markings on them? I don't have any flex strips yet, so I can't do this myself.
/mike
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Well, I don't trust that diagram - for one thing the layout doesn't match the layout of the strings - also , you'll notice it says 24v The 104 bypass cap isn't even shown. It's probably just some drwaing which Ray threw up there.
I did some probing - IT appears that the engineer is correct you can cut BUT you have to add the diode. The +12v feeds the anode of the diode and the leds. The diode cathode feeds the RS resistor (and 104 bypass cap) which supplies VDD to the chip. Without the diode - no pwr for the chip. The cathode is also connected to the cathode of every diode pad (empty or filled) The one diode in a set of five sections feeds all the RS for each 5 section segment. (ie, between the places where the pads are soldered together.)
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I forgot I had one extra strip from the orignal order. I cut it to try and help out with this. It did in fact not work until I jumper the diode location.
I have confirmed that your strips are not dead you need to put either a diode or a jumper on the place marked for a diode. I have a segment setup with a jumper running on a SSC with the test firmware that cycles the colors for you and it is working fine. I will run it for a few hours and see how it does.
The power traces eun down the sides on the bottom and do not connect to the pads as I suspected. The diode is the point every one meter where the power is put into that meter of strip through a diode. Jumpering does leave you open to damaging it if you wire it backwards and a diode would drop a little voltage. I think it would be fine but you can always add a diode where you need it.
RJ
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Could you post a photo of the traces?
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Even Better!
A Video!
http://vimeo.com/23518409
RJ
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Thanks for the information everyone.
I knew you electronics people would figure it out.
Just wanted to give everyone a heads up, before they had a frustrating weekend too.
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Thanks RJ, Turns out it would have been a non-issue for me since I am cutting mine exactly at the 3 meter mark. Question, is the program jumper part of the smart string controller or is it something we would need to add on? George
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Thanks RJ, Turns out it would have been a non-issue for me since I am cutting mine exactly at the 3 meter mark. Question, is the program jumper part of the smart string controller or is it something we would need to add on? George
The jumper is a required part of the SSC and will be in the kit from Bill, its main function with standard firmware is to set program mode or operation mode just like other Lynx hardware (MR-16, Freestyle, SSR4-DMX). With the test firmware it sets two modes of testing.
Cheers
Rick R.
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Thank you Rick for your concise and informative answer!
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good info , little sea sick
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You wouldn't have to make very many cuts before you'd have the pieces to splice a cut and unpowered section to a cut section with the original diode in place.
With RJ's explanation, you could work within the original power design in many situations.
I don't know if that matters though.
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Had anyone considered using these connectors from Ray' store to connect the flex strip?
http://www.aliexpress.com/product-fm/440557083-strip-conector-10mm-for-RGB-color-5050-SMD-led-strip-no-need-soldering-wholesalers.html
I know there could also be a limited use for these new end caps as well:
http://www.aliexpress.com/fm-store/701799/210128048-459153462/Silicon-end-cap-8mm-10mm-12mm-optional.html
Anyways, this has been a very informative thread, thanks !!
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Those are designed for 4 wire, the ones RJ uses are 3 wire.
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yes, your right ... I have from 4-wire strips, so forgot that these would not work on the SS strips.
I have been contemplating the use of 4-wire quick connectors instead of SS 3-wire ones ... mainly because they are cheap in volume and they could work on either 3 or 4 wire ... connections.
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Just wanted to follow up on this - I've cut some of my strips up to make window frames and (of course) now they are acting funny.
In looking at the strips, you mentioned the 1 meter lengths and the diodes and/or pads where diodes should be. But it looks like in the shuffle from full strips to window frames, mine got cut a little different. I will try to explain: Looking at the original / OEM flex strips:
Most if not all of mine seem to start with an R1 resistor, then a segment with a diode, then 3 blank space segments, so the sequence of each 3 LED segment is like:
R1
Diode
Blank Pads
Blank Pads
Blank Pads
[solder joints to next flex strip segment]
R1
Diode
Blank Pads
Blank Pads
Blank Pads
[solder joints to next flex strip segment]
This completes one 1 meter section, then the pattern repeats throughout the strip.
So I cut them up and made the frames thinking as long as I started with either a resistor or diode, I'd be fine. So I wound up with:
Frame 1
Diode
Blank Pads
Blank Pads
Blank Pads
Diode
R1
Diode
Blank Pads
Blank Pads [string works fine to here]
[this is all black]
Diode
Blank Pads
R1
Diode
Diode
Blank Pads
Blank Pads
Blank Pads
Blank Pads
....
Frame 2
R1
Diode
Blank Pads
Blank Pads [String works to here]
[this is all black]
R1
Diode
Blank Pads
Blank Pads
Blank Pads
...
I've checked both frames and they seem to have 12 volt power all the way through. I would not think having extra diodes is a bad thing...5 diodes in parallel would be able to move the same amount of power (and more) compared to one diode - correct? I'm also curious why frame 2 seems to go dark right at the point where the sequence is actually correct (R1, D1, blank, blank, blank) Plus if I add more jumpers to working sections, its not like they go out - they just keep working.
I've tried the exact same controller on a virgin strip and it lights all the way through - so doesn't seem to be a controller issue.
One thought which seems pretty far fetched - The OEM string has VC+, GND, GND, In/Out tabs, I notice the input wires are soldered VC+, GND, [skip], In/out, then throughout the string the tabs are soldered 1:1 across the bridges. When I did mine, I just lumped the two grounds together throughout the string, thinking more ground would be better. Can't see this making a difference, plus why would two segments work and not a third? I've double checked that all segments are 'flowing' correctly...in>out>in>out, etc.
Any thoughts / suggestions are appreciated!
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The most frequent problem I ran across when using cut flex strips is if you cut them somewhere that is not already a solder joint, and then solder to the DIN pad, I think the ground runs right below the DIN pad and more often than not I would bridge the ground and DIN together (check with a continuity meter). The solder just seems to want to wick around the front of the strip and connect to the ground. That caused most of my not working issues. The best way I found to prevent it was to make sure there was a bit of solder mask left when I made the cut to prevent the solder from wicking around the front. They are really touchy.
It doesn't sound like you are doing this, but be aware there are problems if you intend on getting data out of DOUT and it's not a pre-soldered joint.
http://diylightanimation.com/index.php?topic=6020.0
I would check all your connection points and make sure you don't accidentally have the data line connected to ground.