LED FAQ) Building and DIY

[exploziv]

you could use relays so the switch kills both driver power supply wires. one thing would also be nice is PWM dimming. most cheap microcontrollers can do it if paired with the right transistor depending on the power that is being switched.
btw, if they are used on a timer, they can still be left on (very dimm) or pulsing, cause the timer will only kill one wire, and certain plugs can be put in the timer receptacle either way (like EU plugs), so depending on how the user plugs the panel in the timer and the timer in the main plug.. it can certainly happen.
you need to use at least a switch that has 2 separate circuits and they are both off when switch is in off position, this would be the simplest fix, without using any extra electronic components.

 

[Dion]

you could use relays so the switch kills both driver power supply wires. one thing would also be nice is PWM dimming. most cheap microcontrollers can do it if paired with the right transistor depending on the power that is being switched.
btw, if they are used on a timer, they can still be left on (very dimm) or pulsing, cause the timer will only kill one wire, and certain plugs can be put in the timer receptacle either way (like EU plugs), so depending on how the user plugs the panel in the timer and the timer in the main plug.. it can certainly happen.
you need to use at least a switch that has 2 separate circuits and they are both off when switch is in off position, this would be the simplest fix, without using any extra electronic components.

mmm ill have to look into relays-ive had the glowing thing happen before with timers didnt really know what was causing it (other than google searches to electricians forums telling me it happens with dimmers/ more than 1 on/off switch)but found that when i flipped the plug around it stopped-this is smth to trouble shoot now rather than later

can you please explain a bit how to avoid this problem?(the timer ghost ) i dint really understand

PWM is smth to look into down the road as a deluxe feature-eventualy i want to offer PWM dimming, that way there is no need for a timer you just program the light but there are efficiency sacrifices with this kind of dimming-honestly im not a huge fan right now also because of the extra cost and my goal is to bring a 250w light using top bin cxb3590s that is spread for a 120cm wide space to market for less than 600 euro delivered

that would be the cheapest price on the globe right now, even in the usa prices are slightly higher

 

[exploziv]

You need to have both power suppling wires of the driver disconnected from the mains (open circuit). Both the phrase (line) and also neutral.
Don't think pwm will lower efficiency. At 100% circuit will be same as with the leds connected straight to the driver, then as you lower the fill % it's just a fast succesion of 100% and 0%.

 

[Dion]

You need to have both power suppling wires of the driver disconnected from the mains (open circuit). Both the phrase (line) and also neutral.
Don't think pwm will lower efficiency. At 100% circuit will be same as with the leds connected straight to the driver, then as you lower the fill % it's just a fast succesion of 100% and 0%.

ahhh i see


no it wont lower efficency BUT when we dim by reducing current we increase efficiency with PWM we dont increase efficiency when we dim.... kinda doesnt matter too much but if you consider it in photons per watt it less efficient- especially when we dim for longer periods the KWH add up

so its just like 2 disconnects but with 1 button-yes yes good
BUT how does that solve the timer issue?

 

[exploziv]

No. You need to use a relay for that. The switch would only solve the problem if they are turned off from the switch.

 

[jesbuds]

question: are you planning on mounting that pot or just let it dangle?
for casing you can build a box around it with L profiles and sheet alu

Funny you mention that on the pot, I was looking at it for a while the other day going, "How the hell am I going to mount you?" Thinking and thinking about it then as I'm staring at it, I remember at the base is a nut to hold it onto a bracket, doh! It'll all get mounted though, actually got some acrylic ordered last night through an online company that can laser cut sizes much better than what I can do. We'll see how this all works but at this point just happy to see things light up.

Interesting to hear y'all talk about switches as I didn't know some only kill one wire. Know with mine it does shut off both live and neutral since I was paranoid I'd connect things wrong and had tested all connections with my multimeter.

 

[jesbuds]

Just in case anyone wants a laugh....Got both drivers wired up set it on my floor next to a socket (without thinking COBs were basically sitting on the carpet), plugged it in and LEDs off one driver weren't coming on. Didn't have the unit on more than maybe 30-45s and....well we know 3 COBs are working!

They cool down so dang fast I didn't realize how hot they get so quickly, it really isn't too far off to liken these to a CPU chip. Oops, well the burns will help distract my landlord from the old cat pee stains . Now to troubleshoot the other driver/COBs.

 

[exploziv]

that looks kinda too hot for just 45 seconds. have you checked their temp by other means than melted carpet fibers?
I've dropped red hot metal pieces on carpet before and it took like almost 5 seconds to get a noticeable melt. never got any black marks tho. I'd say you either got a crappy carpet in there or your leds are way too hot.

 

[jesbuds]

Cheapest of the cheap carpet, I'm in a pretty cheap apartment. I have the pads to lift the unit when on a solid surface but on the carpet the LEDs were basically flush against carpet. I might not have had the fans on either, can't remember right now but I'll test more.

 

[jesbuds]

One of the wires for the second string of COBs wasn't fully seated on the chip-lok, got it running and this time, tested on a table. They aren't that hot, it was just sitting flush to the carpet causing the burns, stupid stoner mistake. If this test had burned the table I would have been worried.

 

[Boyd Crowder]

nice rig there jes

 

[mugenbao]

nice rig there jes

 

[jesbuds]

Thanks guys, been running it on my test bench for about 4-6 hours so far and no sparks, fires, electrical shocks to myself or overheating. Sure it's warm directly under the LEDs but heatsinks are cool to touch and drivers only get slightly warm.

I will say that when designing this, I saw no use for dimming but after having dimming, I love it and wouldn't build another without.

Fun story #2 - Smoked a bowl with the LEDs on sitting a few feet away, 2 minutes later I look at my LEDs and have that initial moment of panic because I see smoke......only to realize shortly after that it was my own smoke.

Edit: And as someone who likes electronics and seeing things function, it's really cool to see this monstrosity actually work.

 

[mugenbao]

Fun story #2 - Smoked a bowl with the LEDs on sitting a few feet away, 2 minutes later I look at my LEDs and have that initial moment of panic because I see smoke......only to realize shortly after that it was my own smoke.

That's funny as hell, because I did the same thing on my first light. I built it into a small steel enclosure I had sitting around, and there is a bit of a gap around part of the heatsink. The cooling fan sucked the smoke into the case and then blew some of the smoke out directly around the heatsink through that small gap, which made it look like the COB was smoking.

I know that panic, haha.


.

 

[jesbuds]

Grow light? Stupid humans, this is a cat warmer.

Acrylic arrives this week so hopefully be all done by this weekend wooo.

 

[Dion]

Grow light? Stupid humans, this is a cat warmer.

Acrylic arrives this week so hopefully be all done by this weekend wooo.

nice!

i bet they get tanned under there

so acrylic.... forgive me but whats that for?

Im not sure if we are talking about paint or plastic housing

 

[jikko77]

work in progress.
here some pics of what i'm doing or trying to get: (this is the worse drill i've done so far, by hand, i don't have a drill press or collon)



(yeah i had to get them, in the end i didn't had enough heatsink)



the other 2 i still have left.

 

[Dion]

still testing and the casing is causing headache(its 110cm long[43 inches)
in the future I will get a case first and build the light off that rather than build the light then try to get the case custom made

despite the hlg-240 report saying the current is 1900mA I got exactly 1750 off it(posibly loosing about 100mA to the old test leads)

it's finished now I just need to get a case on it and a few final touches and it ships

now testing then a little make up

 

[jesbuds]

nice!

i bet they get tanned under there

so acrylic.... forgive me but whats that for?

Im not sure if we are talking about paint or plastic housing

Yea sorry, plexiglass plastic housing. Really just to keep wires clear of anything, make storage easier and aesthetics.

 

[jesbuds]

work in progress.
here some pics of what i'm doing or trying to get: (this is the worse drill i've done so far, by hand, i don't have a drill press or collon)

Looks great man and I'm in a similar boat with limited tools which is basically: 30+ year old drill, dremel, hacksaw, wire strippers, screwdriver and pliers. Work with what you got and your's looks great, no one is even going to see some minor drill errors on a heatsink .

And Dion, love that setup, looks very clean/professional. If I were better with metal I'd try that for housing but cutting some 1/16" aluminum with a hacksaw gets old quick (so much that I want to make a top frame for the case but just can't bring myself to cut more ).

Edit: Dion, gotta ask, that's (4) 3070's right? Do you have them spaced about 10-12" (25-30cm) apart (looks like 3.5-4ft strip)? Just wondering since that's sorta what I aimed for in mine as far as COB spacing, figured roughly 1sqft per COB.