After using my SST20 660nm red D4SV2 (and E21A 2000K D4V2) every night on the bedside table and absolutely loving having this kind of night lighting, I’d like to make a non-flashlight (mains power) bedside / table lamp with these LEDs, starting with the 660nm reds. I’d also like them to be dimmable. I’ll be carving lampshades from wood and would like to make a bunch of them as a side project.
I’m hoping to find some information on how LEDs like this need to be wired up, what other circuitry or components are required, and how to configure for plugging into mains power (240V in New Zealand) without creating some dodgy fire hazard or burning out the LEDs.
I know nearly nothing about electronics but am keen to learn. I’ve hunted around on YouTube but am struggling to find resources that will give me the information I need without digging through endless hours of vaguely relevant videos typically focused on other specific products.
Hoping someone here may be able to point me towards some good learning resources, how-to guides, or share some tips.
Hardest part is of course the driver. You want to fully convert down to DC, and NOT use a cheap ballast and PWM the beasties, unless you enjoy 100Hz strobing.
What you might want to consider is to find a mains-powered desk lamp, and strip the guts from that. Even if 20bux a pop, it’ll likely cost you more for the driver, switches, etc., that’ll have to go into a homebrew solution. Simply economies of scale.
Then again, IF you can find a driver on AX or somewhere that directly does what you need/want, vs a current-controlled step-down converter, you might get lucky.
It’s doable, for sure, but think needle in haystack.
It might be “cheating”, but I got a few desk-lamps that aren’t run directly from the mains, but use a wall-wart to step down to DC, and take, say, 12VDC input.
That’d be a lot simpler to handle, and you could probably scrounge flashlight drivers (fully current-controlled would be best), and use that to control the LEDs.
You need a MCPCB to solder the LEDs on, with whatever number of LEDs in series to cover your lighting needs (stick to the standard rated current for the LEDs or lower), a heatsink (can be just an aluminium sheet) to mount the MCPCB on and an AC-DC constant current LED driver with dimming capability.
Meanwell for example makes a lot of them : Digikey , with different dimming methods (PWM signal, resistor/potentiometer, DALI…etc).
Chose the current and voltage range suitable for the number of LEDs.
Although using COBS would be easier if you can find RED ones, they can be directly screwed on the heatsink, no need to bother with MCPCBs and reflow soldering.
Thank you both for the info, I appreciate your time.
I’d prefer to do it the ‘right way’ and just learn whatever is involved to get there, rather than cobble together bits from other products without really understanding what I’m doing. Also keen to stick with this specific 660nm LED if possible as I love the light vs other red LEDs.
I’m a complete novice with this stuff so I think I need to start with the basics, for example exactly how the LED attributes (forward voltage, luminous flux, test vs max current etc) dictate what other components can be used with the LEDs, and what/how to calculate this when using multiple LEDs. I’m just struggling to find that kind of information (especially in context and in a novice-friendly format). Links to any useful resources would be appreciated.
You’ve got me pointed in the right direction - thanks thefreeman for the link & details. Clearly I’ve got a bit to learn to work out which of all the drivers and MCPCBs I could work with…
Have you considered building a lamp in the fashion of a flashlight; 1 or more cells, driver, switch, mcpcb w/ led AND a charger board built in with a USB-C (or other) port? Than it can be operated w/o mains power as well as have the cell recharged as necessary.
I have a few like that with a new one being completed right now. I will be showing it here in a week or so when it is done.
Thanks for the suggestion. I hadn’t really considered that, it’s a good idea. I’m keen to go for mains though so that I can give one to my low-tech father who won’t want to bother with charging etc - just plug in and go. Hopefully I can make it look just like a standard table lamp. Your approach may be good for some other ideas I have further down the track. Keen to see what you put together.
Anyway, Hank’s happy to sell me the MCPB from the D4SV2 with the 4x 660nm red LEDs already soldered on, so that should simplify the process a bit.
I figure I then just need to find a suitable heatsink (assuming it could get pretty toasty with 4 LEDs on there at max brightness), then an AC-DC constant current LED driver with dimmer that will work with 3V~4.2V, 10A max current. Then I’m guessing I can just wire in a mains plug with inline switch and I’m good to go.
Emisar quad MCPCPs are wired in parallel, high current low voltage AC-DC LED are less common and more expensive.
Ask if he still has series/parallel configurable MCPCBs, or use individual MCPCBs in series.
And as I mentioned I wouldn’t drive LEDs this hard (2.5A) in a light fixture which is used for considerably longer period than a flashlight, it also generates more heat.
Ideally you want the LEDs in series so you don’t blow them all if one fails, you get more even lighting too.
Constant current driver is required. Don’t exceed the total current of the LEDs. In series, it will be the current of one LED unless it’s also parallel