evilc66 Posted January 12, 2009 Share Posted January 12, 2009 I love those optics. So easy to mount. I'm going to have a lot of those to test with. I ordered 40, 60, and 80 degree Cree optics, and a 30 ETG optics that doesn't mount the same way. Quote Link to comment
sweevo Posted January 18, 2009 Author Share Posted January 18, 2009 My Buckpucks and new soldering iron arrived on friday so I sneeked a few hours here and there this weekend to knock up a basic test system. Having read other people's threadsI knew looking at these things directly would result in temporary blindness but I just couldn't help myself ! So all I've got going at the minute is 3 Cool White XRE's wired up to a 700mA buckpuck controlled by the arduino which fades the LED's in and out in a constant loop. Having not soldered for an age I decided to try out just a few whites for starters as they were a lot cheaper than the blues. As expected the small discs were awkward for soldering but it looks like I managed it without burning any of them out ! Here's a pic of the unit on the go. So all in all I'm really pleased with how the first attempt has gone. I've not run this for any lengthy period of time yet so I've got a bit of play testing to do and of course some more soldering to do so I can see how long 12 XRE's will blind me for ! Quote Link to comment
evilc66 Posted January 19, 2009 Share Posted January 19, 2009 Sweet. What did you end up getting for a soldering iron? Arduino isn't too hard is it? Quote Link to comment
sweevo Posted January 19, 2009 Author Share Posted January 19, 2009 (edited) Sweet. What did you end up getting for a soldering iron? Arduino isn't too hard is it? The Arduino is really easy to use. I know C which helped and i'm sure anyone with a basic grasp of programming/scripting will find it relatively easy too. I think running it with a RTC and LCD Display will be a challenge but that's for stage 3 of my project. I ended up buying a 25W Antex (UK Made) iron. It came with quite a wide tip so I'm going to get the narrower pointed tips for it to see if that makes the soldering a little easier. With regards to the wire used for the LED's. What's the logic in using thicker wire? Less resistance? The cables I used for the XRE's were rated at 6A but I think they're a little on the thick side and make the soldering more difficult. The 1.4A rated cable that I run from the Buckpucks to the connecting blocks didn't seem to get warm (running at 700mA) for the hour that I ran everything last night. As ever, thanks for all your help and input. Edited January 19, 2009 by sweevo Quote Link to comment
evilc66 Posted January 19, 2009 Share Posted January 19, 2009 Sparkfun has a cool little RTC module that you interface to over I2C and has a battery backup too. Fun Gizmos has a really sweet LCD that has RS232 (TTL), SPI and I2C interfaces native to the board. It is missing some basic formatting commands (like character placement) that you need to program the long way. For the wires, I use 24/26awg wire. Plenty small, and enough current capabilities. I don't see a need to go any bigger than that. Quote Link to comment
sweevo Posted January 20, 2009 Author Share Posted January 20, 2009 (edited) Thanks for the info. Will look into those once the unit is up on my tank. Done a bit of testing to see how much heat gets knocked out into the 8" x 5" sinks I bought . Tried 3 XRE's @ 700mA and then two 3's in // at 1000mA ( 500mA per chain). Although after a few hours the sink was only warm I can see that i'm probably going to need some cooling fans when running the final model, as there'll be five times more LED's for only an approx surface area increase of just over three along with an increase in power used. Ordered my 12" x 10" sink ( 0.31 C/W ) today and I've now decided I'm going for 6 x 5 XRE chains run at 24V which will make adding 12V cooling fans nice and easy. One last brief test to do tonight. 3 XRE's at 1000mA. Guess i'll be compelled to look at them just to see how bright they can actually get ! Edited January 20, 2009 by sweevo Quote Link to comment
evilc66 Posted January 20, 2009 Share Posted January 20, 2009 Don't plan on watching TV (or anything else) for a while. Quote Link to comment
sweevo Posted January 21, 2009 Author Share Posted January 21, 2009 (edited) Ordered all the additional hardware last night for the final model. One thing been puzzling me though. I found that when the buckpuck control pin was set to max (5V, which caused the lowest current to be output) the buckpuck was still providing enough current to drive/light the LED's. I was using the 5V Ref pin to power the Arduino so that meant I also had to have power to the buckpuck at all times. This meant I could never get the arduino to stop the LED's being lit. For now this isn't a problem as such (will be using external mains timers to control power to two 24V DC PSU's) but longer term I need to have some way of powering the arduino externally to the buckpucks and also a way of letting the arduino switch the power on/off to the buckpucks too. Anyone got any suggestions? Regards the switch , all I could think of was something like a transistor, controlled/biased by the arduino. I'm guessing it'd have to be meaty as there could be up to 3A being drawn through it from the 3 chains of XRE Whites. Getting the voltage to 5V I wondered about a voltage regulator or using a zener diode or even just a simple potential divider across the 24V maybe? Anyone got any ideas on this one? Edited January 21, 2009 by sweevo Quote Link to comment
evilc66 Posted January 22, 2009 Share Posted January 22, 2009 You would be best to just use a 5v power supply to power the Arduino rather than try to step the voltage down. You can also just drive the puck through a transistor. Bias the transistor using the 5v reference voltage, and switch it with the Arduino. You could just connect the control pin to the output (don't use the 5v reference), but you lose protection for the controller. If you use a seperate power supply, make sure you tie the grounds of the 5v and 24v power supply so the potential is equal. If the input of the puck was opto isolated, you could get away without doing that. Quote Link to comment
sweevo Posted January 22, 2009 Author Share Posted January 22, 2009 You would be best to just use a 5v power supply to power the Arduino rather than try to step the voltage down. You can also just drive the puck through a transistor. Bias the transistor using the 5v reference voltage, and switch it with the Arduino. You could just connect the control pin to the output (don't use the 5v reference), but you lose protection for the controller. Thanks for the advice. Can you just confirm that i'm on the right track with what I think i'll have to do here please, I haven't touched electronics since I left college 20 years ago ! Apologies if my terminology is awful.... After reading your comments I'm guessing i'd need one transistor per buckpuck and that the transister would need to be able to provide 700-1000mA emitter current (that's what the buckpucks will draw ) at 24V (Vce?) when the transistor is biased by the arduino? Quote Link to comment
evilc66 Posted January 22, 2009 Share Posted January 22, 2009 Not quite. The transistor is there as an interface between the Arduino and the control pin on the buckpuck. It's not responsible for any high current switching. You're letting the puck do that. Look at the datasheet here at page 7, figure 14. This gives protection to the micro, but you need to pwm the output (or you can connect it to the analog output pins), and it will chop the light output (fast on and off to perceive dimming). If you go by figure 15, you can connect one of the Arduino analog outputs directly to the control pin for "analog" dimming (the analog output on the Arduino is just an automated pwm signal). The end results are the same. Quote Link to comment
sweevo Posted January 22, 2009 Author Share Posted January 22, 2009 (edited) Fig 15 was the way I had wired the unit up and I couldn't get the buckpuck to turn the LED's Off. I was using PWM and at the highest setting (255) the LED's still wouldn't switch off, the buckpuck was still drawing current [could see approx 50mA on my benchtop PSU]. I did miss out that capacitor though [ one across Ref and LED - ] thinking back as it doesn't give you any kind of value in that sheet. Looks like a 0.1 but 0.1 what? Suppose I could add one in and see what happens maybe as I have a bag of small ones of varying types and sizes. I was a bit worried about just wiring in a randomn capacitor. Didn't want to damage the arduino or the buckpuck. Edited January 22, 2009 by sweevo Quote Link to comment
evilc66 Posted January 22, 2009 Share Posted January 22, 2009 It's just a filtering capacitor. A 0.1uf cap will be fine. It won't make the driver shut off though. Are the LEDs off at 50mA? According to the datasheet the puck is supposed to draw less than 500uA with the control pin high (5v). Have you made sure that the output pin is at 5v? Quote Link to comment
sweevo Posted January 22, 2009 Author Share Posted January 22, 2009 Have you made sure that the output pin is at 5v? Bingo ! Checked the o/p pin and I was only getting 4.09V with the output pin set to either HIGH (digital) or 255 (PWM). The problem was caused by me incorrectly feeding the 5V Ref voltage off the buckpuck to Vin rather than 5V on the power connectors on the arduino board. Because using Vin powered up the board and chip and it "seemed" to be working ok I took it as writ that it was sending out 5V. Thanks ever so much for the help. I can stop thinking about transistors now !!!! The new heatsink arrived today. Need to speak to someone regards the canopy now as i'm hoping to have something custom made. I was worried about the weight originally but I don't think it's going to be as big a problem as what I first thought. Quote Link to comment
evilc66 Posted January 23, 2009 Share Posted January 23, 2009 Nice. Glad it was simple. Quote Link to comment
sweevo Posted February 24, 2009 Author Share Posted February 24, 2009 (edited) Been a while since I posted but I promise i've not been idle. I'm all but ready to start assembling the final unit now and the last design issue I need to decide on is the cooling fans. I've already decided on using two Xilence Red Wings (80mm, 15dB @ 12V), it's just which way to mount them. Originally I was intending to have them blow across the length (12") of the sink as that's the way the fins run. After seeing soundwaves impressive DIY though i'm beginning to think the unit will look far nicer if they're mounted on top of the heatsink itself. I've googled a bit and haven't come across any clever gadget for doing this simply. Apart from drilling the sink and fastening the fans to the heatsink using a 2-4 nuts and long bolts through the heatsink per fan I can't think of another way to mount them. Anyone got any better suggestions? Also for cooling is it better to have the fans draw the air away from the sink or blow cooler air over it? Can't make my mind up on this one! Edited February 24, 2009 by sweevo Quote Link to comment
sweevo Posted March 1, 2009 Author Share Posted March 1, 2009 (edited) Almost ready for assembly now. Just wondered if someone can just put my mind at ease a little by answering a few questions as I'll be running this array at anything up to 5A. First up, I bought a 22V DC PSU (laptop style) rated at 5A, will veroboard be ok with 5A being fed into it? I'm not going to melt it or anything scary am I ? I'll be running six buckpucks in parallel off the veroboard/PSU which is why the current draw could get so high. To begin with i'll probably run at approx 6 x 600mA just to see how the cooling and heatsink cope but longer term I do intend to go higher, especially on the whites. Next up, I had bought a 2.5mm DC socket to plug the laptop PSU connector into and planned to wire that to the veroboard but the more I think about it there more I wonder whether that won't melt with 5A running through it too. There was no rating on the part/packaging when I bought it and any alternatives I've seen online don't seem rated above 5A @ 12V DC. I was wonmdering if it'd be better/safer just to wire direct to the veroboard instead? Lastly, the PSU although rated at 5A only came with a 3A fuse in the plug. I know AC and DC currents aren't the same thing, ie 3A AC != 3A DC. I just wondered if I'm likely to need to upgrade to 5A. The other option I guess would be to buy another of these PSU's and run them at 3A (3 x 1000mA for whites) and 2.1A (2 x 700mA for blues) which might make things easier to manage current wise. Thanks in advance. Edited March 1, 2009 by sweevo Quote Link to comment
evilc66 Posted March 2, 2009 Share Posted March 2, 2009 Don't plan on running 6 LEDs per driver on that power supply. At 22v you can run a max of 5. The veroboard/strip board won't melt. You should coat the traces that are running your power and ground with solder to help increase the current capacity. Bare, the strips won't handle it very well. The fuse is rated for the input side, not the output. At 5A draw on the DC side, it's only 1A on the AC side. A 3A fuse may be a little big for this power supply, but it will work fine. Quote Link to comment
sweevo Posted March 2, 2009 Author Share Posted March 2, 2009 (edited) Don't plan on running 6 LEDs per driver on that power supply. At 22v you can run a max of 5. The veroboard/strip board won't melt. You should coat the traces that are running your power and ground with solder to help increase the current capacity. Bare, the strips won't handle it very well. The fuse is rated for the input side, not the output. At 5A draw on the DC side, it's only 1A on the AC side. A 3A fuse may be a little big for this power supply, but it will work fine. Hi, thanks for the reply. Should've made it things a bit clearer there (sorry) but I'm not planning on running 6 LED's per buckpuck, i'll be running 6 strips ( 6 x @600MA) of 5 LED's. When you say "the strips won't handle it very well" in what way do you mean? I'm beginning to wonder if it'd be a better idea to use a terminal/connecting block or something and wire the power from the DC socket directly to the power terminals where the buckpucks sit on the veroboard, ie so only 1000mA max ever runs through any one strip of veroboard and then for only a few mm. It's really suprised me that there don't seem to be any 5A 24DC rated sockets out there. Really thought they'd be easy to pick up. Best I can lay my hands on is rated at 5A / 12V which I guess equates to 60W of power. Running one at 22V and 5A is 110W which is nearly twice it's rating which I would imagine isn't a good idea. I'd been wanting to use the sockets so I could easily disconnect the unit from the PSU as and when I need to take it off the tank and thought it would be safer if one of my kids decided to pull the cabling while my back was turned etc. I did wonder whether just using a standard molded plug and socket (like a PC monitor etc) would be better as they're rated 6A-10A AC so would (should?) be well within the 5A DC i'd be looking for, ie cut the DC out cable from the PSU, wire up the +ve and -ve to the socket, fit the plug connector into the project box and wire up the buckpucks/veroboard to that. Edited March 2, 2009 by sweevo Quote Link to comment
evilc66 Posted March 2, 2009 Share Posted March 2, 2009 When you say "the strips won't handle it very well" in what way do you mean? I'm beginning to wonder if it'd be a better idea to use a terminal/connecting block or something and wire the power from the DC socket directly to the power terminals where the buckpucks sit on the veroboard, ie so only 1000mA max ever runs through any one strip of veroboard and then for only a few mm. The bare strips on the veroboard won't handle 5A bare, even for only a short distance. Addin solder to bulk it up will just make sure there aren't any problems. Make sure it's pretty consistent as dips and thin spots could create hot spots. I know it's only for a short distance, but better safe than sorry. If each puck is connected to a seperate strip, then thats a different story, and you should be just fine. Quote Link to comment
sweevo Posted March 2, 2009 Author Share Posted March 2, 2009 Think I'll hookup each buckpuck seperately as I'm starting to get a bit worried about burning my house down now the more I think about 5A's coursing through cables !!! As ever, thanks for responding. I really think you should have your very own forum now judging by the number of posts you respond to these days ! Hopefully i'll be assembling this over the next two weeks and will get some pics up along the way. Quote Link to comment
evilc66 Posted March 2, 2009 Share Posted March 2, 2009 Pfft! 5A is nothing. I was used to dealing with 1000A+ DC at the place I used to work at. That kind of current will make your butthole pucker. Don't sweat the 5A. It won't burn your house down. If you ran 5A through a single strip without the extra solder, it might get hot, but not hot enough to start a fire. FR4 fiberglass and mica are self extinguishing, so it's very hard to get something to spontaniously combust. Quote Link to comment
sweevo Posted March 2, 2009 Author Share Posted March 2, 2009 (edited) Think of all the LED's you could drive with 1000A ! What do you think about the 12V / 5A 2.5mm connector? You think that's a safe option at 22V / 5A ? Me being paranoid again I know. I guess I could just see how hot the casing and connector gets when run for a lengthy period of time? Edited March 2, 2009 by sweevo Quote Link to comment
evilc66 Posted March 2, 2009 Share Posted March 2, 2009 It could be borderline, but I think it should work. Watch the heat. Quote Link to comment
sweevo Posted March 6, 2009 Author Share Posted March 6, 2009 (edited) Ok, think i'll go with the molded socket for now and maybe come back to this once I'm ready to box all the circuitry etc. Just a few quick pics as to where i'm now at with this. I've had a bit of spare time this week and the canopy/mount has been finished. First up here's the drilled and tapped 300mm x 250mm heatsink ready for holding 30 XRE's. Next up is the canopy/mount made from 12mm clear acrylic. I had this custom made by a plastics firm as I wanted the final unit to look good on my tank. I spent hours on google looking for something I could use for mounting the heatsink but in the end came up with this idea after seeing some acrylic tables somewhere. The arcylic was buffed and finished so all that was left to do was cut a suitable sized hole in it for all the XRE's and their Optics to fit through. Lucky for me my Dad's a DIY whiz so I left this to him! Once the heatsink was securely fastened to the mount I started soldering all the LED's. The first few weren't exactly tidy but after a few I figured it all out and made a decent (IMO) job of soldering all the chains. So now it's time to program the Arduino to drive the six chains of LED's and also control the cooling fans which i'll cover in my next post. Edited March 6, 2009 by sweevo Quote Link to comment
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