DIY Multichip LED Build

[jsjonesrdh]

Hey guys, being completely new to electronics I realize this is a 101 type question but after I wire my led in parallel, where to I take my measurements with the multimeter to find the.current for each channel? Do I measure on the + and- terminal for each led channel?

What would be the best way to solder the 5wires to the lead of the driver. Should I braid them together and then solder or is there some connector I should use. What gauge of wire should I use between the driver and the led. I have some 18 and 20 at home already.

Thanks

[jsjonesrdh]

Nevermind on measuring current. I spent a few hours learning how to do this and I feel I have a much better grasp on the topic.

[Zeuthen]

@Screener and other guys planning on using the Arduino+LDD-H solution:

I've been playing with the idea of stacking the driver boards. I think I've come up with an idea that might just work - generating the PWM signals on the driver board. Sparkfun (and others) sell a daisy chainable RGB LED driver IC: WS2801. Each IC can generate 3 PWM signals and is adressable, so you can control each PWM signal using just two pins on the Arduino. Thus, two of those is enough to generate PWM signals for the 5 Dream Chip channels and the fan PWM.

The temperature sensor DS18B20 is also adressable, so this is easy to bring to the next board.

Only thing I haven't got a solution for (yet) is the fan tachyometer (for fan RPM readout) - I guess you could use a multiplexer for this.

Oh, and the advantages of generating PWM on the driver board:

• As long as the driver board has power, the PWM signal should continue to work, even if the Arduino is offline (I still need to confirm this, though)
• PWM signal has to travel a shorter distance, which is more robust
• You don't have to share PWM signals between separate dream chips - allows for fine tuning
• You don't need a lot of PWM channels on the Arduino

Only disadvantage is that IC soldering is challenging and may prove to be beyond my soldering skills...

Any input/ideas/caveats that I missed?


Best,
Esben

[jedo]

Please take a look at the PCA9685(16-channel, 12-bit PWM Fm+ I2C-bus LED controller)

[Zeuthen]

Please take a look at the PCA9685(16-channel, 12-bit PWM Fm+ I2C-bus LED controller)

Yes, I think this PWM controller is good for LED lighting, but in this particular application, where each PCB has three LDD-H drivers, less is more - I want to make the PCB design small (smaller than 5cm by 10cm) so that I get cheap PCB prototypes from IteadStudio. I also want to keep the number of different PCB designs to a minimum, so I want the PCB design to support the different board configurations needed.

For the PCA9685, I like:

• 12-bit PWM - dimming will be smooooth!
• I2C bus support

BUT - pin spacing is only 0.65mm, making it next to impossible to DIY solder...

For this particular application I need a 3-channel PWM generator with a large pin spacing, 2.54mm (or 0.1") being optimal.

Best,
Esben

[ronreef]

FYI: http://www.ledgroupbuy.com/inventron...-driver-700ma/

Ron

[jsjonesrdh]

Hey all,

What is the best way to solder the 5 wires to the wire from the driver? Is there a connection I should use to assist or do I just braid all 5 wires with the driver lead, solder and shrink wrap?

[Lasse]

I´m normally use some type of terminals but sold and shrink wrap works also. Let your overall design determine.

Sincerely Lasse

[leedoherty]

Hi guys my 50 led chip turned up today can anybody tell me if this power supply will work with five meanwell ldd-700-h ?
http://www.ebay.co.uk/itm/36V-4-2A-s...item337ac44e96

thanks in advance Lee

[Lasse]

Yes I think so - I´m not sure because someone said that the LDD 700 demand around 3V by them self. But according to the spec this can be adjusted to give around 40 V. I know that the Meanwell works that way and this look like a copy,

Sincerely Lasse

[leedoherty]

hi Lasse do you think this one would be better ? http://www.circuitspecialists.eu/pow...8v-5a-240w-psu

Thanks again

[Lasse]

hi Lasse do you think this one would be better ? http://www.circuitspecialists.eu/pow...8v-5a-240w-psu

Thanks again

Nja (is Swedish for yes/no) You can´t put that lower than around 43 V and there will be a lot of energy as heat. Probably the 36 V variant is best but I really do not know. What do our Danish friend think?

Sincerely Lasse

[ronreef]

FYI- Today AC-RC shared the following (Paraphrased):

"“EPISTAR chip assembly guide”. In brief, there are 3 major components to the LED assembly process:
1) Pure red copper carrier
2) 99.999 purity gold wire
3) Dow Corning silicon sealant. Per kg equal to USD952.00. Not only can it enhance heat dissipation but is very clear like glass. This same sealant was used in the assembly of all Dream Chips.

Compare the above to some of other cheaper multichips sold out there: Copper wire. China made sealant which is USD48/kg. Aluminum carrier. Which means that even with the best cooler and thermal grease you still cannot avoid burned out LED's.

Also, AC-RC has official contacts with Meanwell. Group buys for Meanwell drivers are possible now!

Also, AC-RC is beginning to manufacture the flexible arm for rimless tanks. On the initial test, the arm was loaded with 1.2kg and held."

Ron

[dwolson2]

Hey, would that mean we could get the LDD drivers on a group buy? If so, how much would they be?

[ronreef]

Yes, AC-RC can arrange group buys with Meanwell.