Wiring a buckpuck to Arduino

[h3llphyre]

I did miss that in the datasheet, so I'm sorry for going off on you (and your dad). Not sure why I did that.

 

My concern was two fold though. First, I have seen far too many buck drivers do odd things when anything but the LED is connected to the LED- side of the circuit. That part of the circuit is typically drained through the chip, so bypassing that can produce odd results. Not all drivers are built this way though. Second, Luxdrive's datasheets are historically inacurate, so I take things like that with a grain of salt.

 

It's okay, almost ALL of TI's LED driver chips react the way you were speaking of. It's too bad we don't know what's being used inside of the Buckpucks. Of course, if we did, we'd realize it's all of $5 worth of parts

[evilc66]

Oh, I know it's only $5 in parts, and that's only if you buy the parts in the US. Outsource to China and you could do it for $3. I'm building a few different driver designs, so I'm familiar with the costs. Funny thing is, the inductor usually costs more than the driver IC!

[azraely]

So I'm just now trying to wire my Buckpucks up to the Arduino using the posted diagram in this thread and from the Buckpuck data sheet. But for the life of me I cannot get anything to work. I assume I'm missing something fairly obvious.

 

I've made a diagram using Fritzing to show my circuit so far.

 

 

Pin 9 on the Arduino is connected to a 5k resistor and then to the base pin of a 2n4403 transistor

REF off the Buckpuck is connected to the Emitter Pin of the 2n4403 through another 5k resistor

CTRL off the Buckpuck is connected to the Collector Pin of the 2n4403

 

as far as I can tell this is the same the diagram posted earlier in this thread.

I think I'm missing something to do the ground connection.

 

Can anyone have a look at my diagram and point me in the direction of what I'm missing?

[evilc66]

Have you actually verified that you are addressing the right pin in software? Put a 5mm LED and a 10k resistor on the output pin and see if it lights.

[azraely]

I got it working finally.

 

Here is the diagram of my circuit.

 

 

I thought the buckpuck had its own 5v reference? For whatever reason it was not supplying 5v to the transistor to be controlled by the base pin. As soon as I added in the arduino's 5v to the transistor emitter pin it worked.

 

Is this correct or will I damage my arduino or buckpuck running it this way?

[cptbjorn]

is the ground of the arduino attached to the -vin pin of the buckpuck? if the arduino is running from a separate power supply than the buckpucks and the two grounds are isolated then dimming won't work and will cause the symptoms you were seeing.

 

connecting either the two grounds or the two 5v together will fix it, it seems like you figured out the 5v part. just a warning though, with the arduino 5v and the buckpuck 5v reference connected together, if the two grounds get connected now weird stuff might happen. i'd do the grounds instead.

[djmx2002]

Hi

 

I am sorry to bump the topic up again, but i got a question, i am planning to run two moon lights with this driver off my arduino board.

 

I would like to have the lights dimmable so i can mimik natural moon cycles.

 

i am currently looking at getting this driver:

http://www.ledsupply.com/03021-d-e-350.php

 

would that work for 2 350ma 3.3v leds? and if so how would i go about dimming them?

 

Thanks

Motti

[nanotrevor]

puck will work for 2 moonlights, that what i use, except the wired ones. you would need to wire the ctrl from the puck to an open pwm pin on the arduino, then write a code for it.

[MrBill2u]

I am planning on hooking up my buckpucks next week. From the data sheet it looks like grounding LED- from the buckpuck and just letting the arduino supply 5v from the pwm pins would work. Has anyone actually done this with buckpucks? If I need to head out and pick up some transistors I would like to know

[djmx2002]

I just ordered some transistors from china. I'll place an order for the buckpuck driver today. An I'll try. I am going to run one 10v power supply into 3 different transistors hooked up to 3 different PWM output pins.

 

I just got my arduino couple days ago and started getting the hang of it

[ScooterGirl]

It's me, NightAtTheOpera (I don't know how I managed to get a new screen name; I must have set up a different account). Here's my update on how this project is going: it isn't! When I first decided I wanted a reef tank the inhabitants of my FW planted tank were almost 5 years old (I only have room for 1 tank). I figured it was only a matter of time before they passed on and I could start my reef so I wanted to get the planning for the LED fixture done. That was nearly 2 years ago and my FW swords (and their lone oto cat friend) are still going strong even though they are nearly 7! All the stuff I bought (including a beautiful custom Tenecor tank) is sitting in the back shed gathering dust, some of which is obsolete (I see the Uno is now the Arduino of choice instead of the Duemilinove). To add insult to injury the Arduino sketch I had written, which included moon phase and random storms in addition to the usual sunrise/sunset, was on a laptop which bombed and I didn't have a backup (in the dictionary there is a picture of me next to "stupid"). So here I am, again, revisiting all I have forgotten hoping I don't have to wait another two years to put some of this knowledge into practice.

[BruinReefer1]

I finally got my Arduino to PWM dim my lights through the buckpuck. I just wired everything up the way the data sheet said to and then split the grounds, one wire goes to the Arduino ground the other goes to the ground of of the source of Vin. When I tried tying the grounds together, it never worked. If they were tied to the Arduino gnd then you would get PWM but very dim light, and if you tied them to the Vin source gnd you would get light but bypass the arduino completely. So in desperation I split them up and prayed. And it worked! So happy. Just thought I'd share this little learning experience.

[Deckoz2302]

...you know, you could of just used an opto-isolator...