I'm planning a project where I will put 50 or so LEDs on a big map (the kind you hang on the wall and put pins in). I will stick the bare LEDs (3mm) through premade small holes (one for each pin) and then connect the pins on the backside with dupont wires (need that for the other end, LED driver cards).
Here comes the problem, the pins of the LED easily comes lose from the dupont female connector.
I will do the wiring of this on-site and prefer not to stand and solder all that.
I just tried applying shrink tube (like 3mm or so inside diameter) that barely fitted over a single female connector. Well it shrunk around the LED pin but not enough to really secure it.
I know there are pre-wired LEDs but they would be good for mounting through the map and they have a resistor built-on them (for 12v). All leds will be connected to a few Adafruit TLC5947 PWM LED drivers and they already have resistors.
Is there any smart way to connect standalone LEDs to cables without soldering with good (permanent) connection?
Hadn't thought about that but I get the feeling that stripped 28 (?) AWG wires around LED pins wouldn't be secure enough.
I've seen there is shrink tube with adhesive, might try that.
Edit:
Another way would perhaps to use a plier and bend the LED pin (once through the map) several times in straight angles, should make it harder for it the get loose. Or use an even smaller shrink tube first around upper part of the LED pin. But I don't look forward to do this complex because I need to repeat it a 100 times.
Stripped wires wrapped around LED legs is very secure. The legs are square, so its just like wrapping around a socket pin.
This box has been running for 3 years, the LEDs are soldered to perfboard and all are wirewrapped.
All the black & white wires to the sides are the backs of the LEDs.
And to make it worse, the MAX7219 that drives the 8 digits sees 3 LEDs in parallel with one current limit resistor - high brightness LEDs we used, so even if an LED eventually fails, the other 2 will see higher current but still well below 20mA.
Oh yeah - that's 30 guage wire, not 28.
This board could make it easier for you to breakout the MAX7219 signals to 64 individual LEDs, and can be daisy chained for more.
Short video of it driving 8 LEDs here: http://www.crossroadsfencing.com/BobuinoRev17/
Thanks a lot, just tested wire wrapping as suggested on a LED with a small wire. Much stronger than I thought. I will use this method. I have a good wire stripper to use.
I'm not using the MAX7219, went for a more controllable way with the Adafruit TLC5947 breakout board, but more expensive also (since I need 3 of them).
I can solder decently (getting by), e.g. have been doing that this evening for the project, the board which have a dc power jack and screw terminal blocks for 5v to the Yún and PWM driver cards.
I will also solder the angled header connector plugs for the breakout boards. These tasks are nothing new for me.
Nothing advanced, you pros probably can do it blindfolded.
As I wrote briefly in the text, but let me clarify: I don't want to bring the solder station to the site (my office place) where this will be completed, standing up and soldering all those LED pins "freehand" one at a time with interruptions. Plus it won't be possible to remove the LEDs if they're soldered, without cutting the legs. And don't say desoldering - won't have any equipment for that left there when this is complete.
Just ordered some small shrink tube, it can be used to isolate the pins and wires plus secure the wire wrapping even more.
So, can you see that there is a use for not soldering?
No, knitting is not for me. Although other people find it relaxing to do in the coffee breaks at work.
So I begun the project and it turns out that wire wrapping this is easier said than done. I stripped the dupont ribbon into 2 cables (one for each LED leg) but that makes it a bit harder to wire wrap.
So I'm falling back to bending the legs instead. Non-reversible but will have to do.
I remove the plastic part of the dupont female connector, put on a short bit of shrink tube on each cable and bend it slightly so the LED leg can pass through it, then do a double bend of it over the dupont connector, puts the shrink tube in place and test the LED with a battery. Which is good - found a blue LED among all the reds (clear casing, couldn't tell until it was activated). Finally I use the heat gun on a batch of mounted LEDs.
Aqualize:
So I begun the project and it turns out that wire wrapping this is easier said than done. I stripped the Dupont ribbon into 2 cables (one for each LED leg) but that makes it a bit harder to wire wrap.
I do hope you do not imagine for one moment that you can "wire wrap" with other than wire wrap wire sold specifically for the purpose? Or single strand telephone wire. Multi-strand wire - such as the "Dupont" pre-wired cables, is completely unsuitable.
On the other hand, the "Dupont" female connectors should fit quite well onto LED wires (as long as there is no tension to pull them off) - you can use the two-wire sleeves to make a neat push-on connector.
Well didn't know there was special wires for wirewrapping. I actually did try to do it with the dupont cables. But as noted it didn't good too good in practice so I abandoned it.
There is possibility of tension and LED legs don't lock so hard as the dupont male connectors so just using female connectors would cut it.
Anyway I've worked on this on and off and is almost done with mounting all the LEDs.
