You might want to note that when pwm-ing certain fans using arduino or arduino based controllers they have a very audible "whine" due to the arduino's default pwm frequency of ~490hz(well within audible range). There's 2 ways to fix this, the first is to put a 220uf cap in series with the fan you're driving, this will smooth the pulses and reduce the whine (making the digital signal "look" more like a analog one). The second involves changing the switching frequency of the timers responsible for the arduino's pwm outputs see http://playground.arduino.cc/Main/TimerPWMCheatsheet#.Uxw12PldX5M Also be sure to note that if you change timer TCCR0B, it affects millis() and delay() which will throw off any timing dependent parts of your code, so it's best not to mess with that timer if you don't have to. This is just something I found out when experimenting with driving 4 pin and 3 pin fans using your scw circuit:beer:
Meanwell LDD driver: for those who want to dim to 0 using Arduino
- Thread starter pwreef
- Start date
Hi guys,...question, what do you use for a base to mount your various boards to with stand offs? I want to mount my 5up board, arduino, and a couple over shields to a base of some kind of which I can then mount the base in a project box for easy removal. I don't know what I should be searching for. Thanks,---Rick
Ligershark
Member
Could this adapter (along with a scw) be used on one of the coralux boards to allow me to power my fans or would I have to beg O2 to let me purchase one of his boards and do a lot of desoldering? I also have their fan control but if I could use my switching power supply to power my fans this would make me very happy.
For cheap way use perf board from local radio shack brown stuff with holes cut it to fit
I used Velcro to stick mine down in to a box with 2 proto shields stacked on top also ran arduino at 11v and used a outside 5v walwart to run all the probes. So arduino heat was not a problem. I have seen people use metal and plastic and wood inside there final enclosure
I used Velcro to stick mine down in to a box with 2 proto shields stacked on top also ran arduino at 11v and used a outside 5v walwart to run all the probes. So arduino heat was not a problem. I have seen people use metal and plastic and wood inside there final enclosure
Ligershark
Member
I have mine "floating". Using 4-40 screws with nylon washers touching the board and nuts on both sides of the washers. This creates a stand off and allows air under the board. If I was going to mount it in a project box I would consider this method but with acrylic/lexan. I am looking into using nylon screws, washers, and standoffs as well.
Idefixes
New member
I'm using Phillips PMBT2222A switching transistors (SOT-23 package) rated for 40V/600ma.
<center> <table><tbody><tr><td style="text-align:centervertical-align:top;" width="">
</td></tr></tbody></table></center>
Idefixes
New member
Thanks....
_shorty_
New member
Hey guys, a few questions:
Are the traces on Rasco's latest 4 x LDD-L board sufficient for driving the LDD-1500L's? Any other boards floating out there for this purpose? Or is that my best bet? Has anyone found a mounting socket for these LDD-L chips, or most just solder straight to the board?
Are the traces on Rasco's latest 4 x LDD-L board sufficient for driving the LDD-1500L's? Any other boards floating out there for this purpose? Or is that my best bet? Has anyone found a mounting socket for these LDD-L chips, or most just solder straight to the board?
Rrasco's board should be OK trace wise for the LDD-1500L. Just use the conventional DIL24-6 machined pin chip holders that were commonly used earlier in this thread. The LDD-1500L has one pin IIRC that's in a different position than the LDD-H. The PWM input pin has been moved from pin #22 to pin #21 You can overcome this design change by simply soldering pin #21 to Pin #22 on each of your chip holders before soldering the chip holder to the PcB. Easy peasy!
:beer:
Normally I get an Email notification first. DigKey's pretty good about that. I just got a box of stuff from them today LOL. Bought a bazillion .047uf caps and some other stuff for the A6211 drivers that I was running short on. I just finished soldering up a 2000ma version of the little LDD-H replacement version. It's pushing 1970ma into an old BridgeLux BXRA-C4500 right now! Definitely pushing the ragged edge on such a tiny PcB... I'm seeing 68C at the copper heat sink with a fan blowing across it. Take away the airflow and it's 130C in less than a minute. Thank God for thermal protection circuits! Provided a good fan and some cooling failure logic were employed.... These might be an option for really current hungry led builds.
LOL! I'm guessing we'll both be surprised. I don't need 100 more. Was that the Mega screw shield? Does the RTC work correctly?
