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There have been 156 items by Magpie (Search limited from 10-May 23)
#38545 Powerful Aquarium Lighting
Posted by Magpie on 05 November 2012 - 09:56 AM in General Discussion
#38645 Powerful Aquarium Lighting
Posted by Magpie on 06 November 2012 - 10:23 PM in General Discussion
I think you should build something soon, but I have a different idea for you for control.
the netduino can talk SPI and the attiny can talk SPI. so you could drop the tlc5940s completely.
Just have the netduino set the dimming level direct to the attiny via SPI. The only trouble with this is you would loose one channel of PWM, giving you two outputs per attiny.
Although if you can handle a small blink while the communication is done you could have 3 channels.
Also I have never written any SPI code in AVR so you would be on your own there.
L1 will be ok, it just needs to fit mechanically and I think it will fit but it will be tight.
If it doesn't fit you can easily make it fit by soldering L1 just off centre or filing a small notch into the ic socket.
You understand you need to use a socket dont you? I am not sure if I made this clear.
I tried editing the pad offset, but every time I pressed OK, and went back in to the settings, it had gone back to zero?
Right click on the footprint and Open the footprint in the module editor. Set the working library to say 'Andrew' and put all your mods as you do them in here. Create a new part from what is in the editor and save it into your footprint library. At this point you can save it as you make changes. Once it is done then delete the old footprints and place the new footprints into your pcb. The tracks may be no longer connected, so reconnect them using your knowledge of grids and snap to.
One day when I get something looking good made I will post about my latest version, hopefully soon.
Yes I think before the final board is built you could optimise, but it is so hard to get the perfect design from scratch. It is iterative and I think 2 iterations will be your minimum.Let me know how you get on with your new boards, out of interest I know you have dropped a channel, but how small do you think I could realistically drop these boards to? I don't know if I definitely will, especially if these boards work, but I may lay it all out on one big board eventually with the TLC board built in and the power distribution for the 30 channels will be much more elegant and a lot of the connectors could be dropped. I could essentially get away with a GO! bus connector and a power plug, but this really is dreaming ahead!
If you get this first board made in small quanties, turn it on then I think you will find unexpected things, good and bad, especially in regards to the lighting aspect of it.
#38474 Powerful Aquarium Lighting
Posted by Magpie on 03 November 2012 - 11:47 PM in General Discussion
#37372 Powerful Aquarium Lighting
Posted by Magpie on 18 October 2012 - 08:13 AM in General Discussion
#36036 Powerful Aquarium Lighting
Posted by Magpie on 26 September 2012 - 11:11 PM in General Discussion
#38664 Powerful Aquarium Lighting
Posted by Magpie on 07 November 2012 - 09:54 AM in General Discussion
pcb manufacturers
Or probably go with seeed.
Try editing the yellow pcb outline layer, I just looked at your board there is loads of room, but you may just have to reduce the copper pour a fraction.
Just fit (edit) the pcb edges to be 50mm apart. and move the copper pour to be at least say 1mm away. Move the fiducials too or you can just delete them.
Or when you are completely done with the other stuff I can do this step for you. I gave it a quick test it took just a few minutes.
the price from seeed is going to be $US 35.00 and if you waste $15 on something you dont want then you get free postage. The have a resistor book 805, but at $60 it is very expensive.
when you order from seeed you are not paying for service so do everything they say and it will be ok. I forgot my order number on one board but it didn't matter it still came. This time I put it under a big inductor so no-one could see it.
#39923 Powerful Aquarium Lighting
Posted by Magpie on 22 November 2012 - 01:49 AM in General Discussion
#43102 Powerful Aquarium Lighting
Posted by Magpie on 10 January 2013 - 12:57 PM in General Discussion
Heres the project files for steff4.
You need Atmel studio 6 to compile it.
A few things to do to modify it to your purposes.
The main file is Steff4.c
the others are mainly defines and historical. they dont need changing.
Set the fuses on the Attiny to what is at the top of Steff4.c in the comments.
Careful with the fuses you can actually brick it if you are careless, I did this once.
steff4 is only two channel and you have to change the code to 3 channel. 0, 1 and 2
So create a few more defines eg. //#define PWM_OCR_REGISTER_2
also create another section in main for channel 3 that uses the channel 3 defines.
You have to set the all the defines 0, 1 and 2 to be correct for your hardware, so you need the attinyX61 data sheet, your hardware should be very similar to mine.
ReadPWMRegister and WritePWMRegister need to be set whether you are using the positive part of the pulse as on or the negative. If you get it wrong it will turn fully on. This is where the current limiter will save you. Your led wont like 5 volts.
When you get that working and only then, uncomment the dimmer section for each channel in main(), also check any defines used here are correct.
Todo:
I have to fix the function
U16 GetLoadCurrent(S16 sensorCurrent, U16 currentPWMSetting)
to more accurately get the load current from its parameters, as I mentioned before we only measure the fet current.
Lastly I could optimise and or use interrupts, or I could neglect them, it seems to work fine without them.
No doubt you will have many queries about my code, hopefully you can understand it.
I am sure most embedded C people would have a nightmare about the lack of efficiency if they saw it.
You can also run stuff in the simulator, although you have to break and then change variable values to get into some of the code sections.
Attached Files
- Steff4.zip 15.97KB 2 downloads
#42694 Powerful Aquarium Lighting
Posted by Magpie on 04 January 2013 - 11:41 AM in General Discussion
Hi Andy We are just having the hottest day in Hobart for around 40 years, 41.6C. I am sitting with a wet cloth on my head trying to cool down. Did you buy the house? If you did I hope you have a dedicated Aquarium room. the voltage across RL should be 5volts (+/- say 5%) at low currents ( high load resistance) and up till the current limiter kicks in. The Attiny is happy with 3.3v up to 5.5 volts and 5.04 volts sounds just right. You need two current settings very low and normal. Use say 30mA to test for shorts and then say 100mA to see if the led works and then you can probably discard the current limiter for that board.
Cant get some of the links for digikey. the 0.1uf are ok.
goto go sorry back in a few days.
#40199 Powerful Aquarium Lighting
Posted by Magpie on 25 November 2012 - 10:45 PM in General Discussion
Lets face it was your diligence not mine. I normally just buy the first thing.Thanks those caps got me down to about £70!
I wouldn't change the BJTS they are good quality and not so expensive and have been used in Steff2.
I think Atten 858D , (Dave does a video too, #167) do a budget heat gun (dont get ZHIAOXIN 858D and YiHUA 858D, and check earthing before using), but If you want to save money a small wedge shaped soldering tip would probably be good enough for the whole job..
Copper braid.Can you think of anything else that will be useful?
I have had my own mcpcbs manufactured. mcpcb I think it was $30 for 600 peices + $170 for tooling postage and TT payment. <sigh>
You can mount them on FR4 but need thermal vias. Each led doesn't need a huge amount of Al and it depends on a few factors but you can definitely get away with 50mm x 50mm for each XTE or XPG led. Probably even less. Heat sink at the back mean you can place them closer together, but they make a lot of light.
I am using Steff2 in my workshop and it gives enough light, maybe a little more than a single fluoro. 21 leds @ maybe 300mA. I don't think heat will be a big problem.
my calc was 3 x 500mA x 3.15 volts = 4.725W
+ attiny and gate drivers 5v x 100ma = .5W
+ inefficiency = .5W
Total power for 3 channels on one board = 5.725W @ 5v = 1.1 amps.
? each led has its own channel, in this case there is no series or parrallel. In the 12v 24v, and 36v designs you have the led strings in series. You cant really parrallel the leds without individual power resistors to share the currents equally, this is wasteful so not considered.I'll go to really plain terms now, so in terms of voltage drop in series this would be 3.15v per LED so you would need say 12v, but we get away with 5v as the channels run in parallel right?
Current i.e. the 1 or 1.5 amps we will supply can be larger than the required 700ma plus any other losses, as the circuit will only take what it needs right? Would this increase if say we needed 5 LEDs in a row to say 4A or does current not drop like voltages does in series hence it would still be 1 - 1.5A?
So here's where I get confused, where do Watts come in to the equation?
For example will my 5v 1A wall wart be able to power all 10 of my boards and I guess I would need to distribute the power in a parallel design between the 10 boards right?
If you run 10 boards or 30 channels of 1 led then you will need 1 x 11 amp 5 volt supply. Or you can use 5 x 2.2 amp supplies or 10 x 1.1amp supplies. Dont parrallel the supplies just join the negatives as common. Keep the the positives of the supplies separate to each other.
Try not to overload a supply, you can probably use standard 1amp wall warts but maybe turn the power down a smidge. you can do this in the attiny firmware so that the Netduino firmware cannot cause failure. Check the warmth of the Wall wart while at full load. You don't really need to use wall warts there are other more efficient supplies.
Also I would put a smoke detector in your lab especially while still in development.
#39942 Powerful Aquarium Lighting
Posted by Magpie on 22 November 2012 - 12:10 PM in General Discussion
Try these.
445-1369-1-ND
on the caps you can go down to 16v which still leaves a comfortable safety factor. None of the caps need accurate tolerances or temp coefficients.
the fets should be at least 20v.
same with the bjts.
I probably waste a bit of my money but then again we aren't just about to buy a house.
#35937 Powerful Aquarium Lighting
Posted by Magpie on 25 September 2012 - 02:16 AM in General Discussion
I have done, I found it quicker now that I know what I am trying to acheive. If you had a lot of obvious connections then I think that the autoroute can do those fairly easily.I've been playing around trying to do the track widths, do you place all the tracks yourself
The ratsnest will dissappear as each node is fully connected. If you are using vias for higher current paths then you can use multiple.and if so how do you make sure you are connecting up correctly/ deal with vias?
Default for thin, 8mm for thick and say 3mm if it is carrying some current. But reduce these widths just for segments where it is necessary.What widths do you think I should be aiming for, for my thin, medium and thick traces and what clearances would I need?
Do your placement first obviously.
I haven't looked have you changed anything since last time I looked?In terms of my layout, which is similar(ish) to yours can you see anything that will/may cause me a glaring issue?
Sorry Andrew, I was actually Sailing all weekend, it was fantastic.
Did you sort out how to change track widths, I know it is very cumbersome.
You probably found this out already but
assign a track to a track type in the digital rules.
When you lay it out it will take the track width of the track type.
If you want to temporarily make some tracks a different width such as for the ground plane, Where the Kelvin connections carry a tiny current and the power ground has high current you can just change the track width for the track type(eg. High Current) while you lay that track. Then set it back to normal.
Also sometime you want to run the track thin into the pins but run it fat for most of the length.
First run it thin, then change the track thickness for the track type and right click and adjust the track thickness on the segments that you want thicker.
for the thicknesses
Connections into the processor only need to be thin. Power tracks make thick. Tracks on the ouput stage make thick as you can but thin them down as they feed into the component legs. It basically comes down to the current through the track. 8mm wouldn't be amiss joining the inductor to the Fet and the diode, if you can fit that much.
I quite liked my posistioning of the components, to minimise track lengths for the high current tracks. But maybe you want the connectors to be organised differently.
As for the Kelvin connections run them as pairs or threes lik it did. The only place the ground of the kelvin connection touches ground is at the sense resistor.
the point is we want to measure the voltage of the ground at the sense resistor compared to ground at the micro, but using only the minimum current we can to do it. (Conceptually tricky). Also we want the minimum induced noise so we run the differential inputs right next to each other, for as long as posible.
Hope this helps
#32886 Powerful Aquarium Lighting
Posted by Magpie on 30 July 2012 - 01:07 AM in General Discussion
Seen plenty of similar errors myself.
the not connected, you just need to zoom in an check it is connected, I think the colour changes in the middle.
If you don't want to connect to a pin, you put a "NO Connect" symbol on blue cross. It's just a message to the DRC.
Also if you label a node, and want to use this node somewhere else you might have mistakenly give a different name.
There are also power markers, that you place like components, these may have the same name as labels but are different.
Eg. you have to label a node as GND if you want to use it in different places, but you also need to attach a power marker to it which will be called Gnd.
You have to say where the power is coming from, you can either ignore it or edit a connectors pin, if it is coming off board.ErrType(3): Pin connected to some others pins but no pin to drive it
@ (1.6750 ",1.2000 "): Pin 15 (power_in) of component IC1 is not driven (Net 10).
Ignoring it is fine if you are sure what is providing power. I did manage to get my design pass DRC but it was a bit of frigging around.
My mount holes are stupidly big on my board. I think my power vias could be bigger.
#30769 Powerful Aquarium Lighting
Posted by Magpie on 16 June 2012 - 12:30 PM in General Discussion
The details are on my domestic lights project . It is based on the Attiny but with some improvements.
I hope this helps.<br>
#30795 Powerful Aquarium Lighting
Posted by Magpie on 17 June 2012 - 01:44 AM in General Discussion
#29736 Powerful Aquarium Lighting
Posted by Magpie on 25 May 2012 - 01:50 AM in General Discussion
Finally I have my lights working.Hope your boards work out fine, you will have to let me know how they go.
I haven't used or really looked at the Go architecture yet, but I think it may suit your project.
#27976 Powerful Aquarium Lighting
Posted by Magpie on 23 April 2012 - 11:28 PM in General Discussion
Glad it is going well.
The good news for me is my NCL30160 boards finally arrived, so I may as well power them up.
I am going to do it at 24 volts and put Transient suppressor diodes on the inputs for a bit of protection.
I will let you know how it goes.
OnSemi assured me they tested the chips and said it was probably overheating.
If you look at the photo I posted on the SteffShield thread you will have to agree with them.
But as it is decision time for you, I will give you some thoughts becasue as you know proscrastination is the enemy of success.
I would go 12 volts per channel and use a mains down to 12v supply. This means you can add extra power to any channel if you need it, but you will need the single inductor per channel.
I like the meanwell supplies and I would get one that is highly efficient, this doesn't mean super expensive. ie. higher than 90% at rated current. Try a recent model of the meanwell ones.
The one in you picture looks ok but you really cant tell from a picture.
As far as Amps go .What other parts do I need and what adjustments need to be made in terms of the power supply?
Work in watts and then at the last minute divide it into amps.
Add other power requirements and led requirements.
the leds will be say 30 x 3 watts = 90 watts
other stuff say 50 watts???
= 140 watts
add some spare capacity and you have say 250-350 watts.
divide by volts and you have say 25 amps.
so that is a fairly hefty supply.
ps. I know this sounds like a computer psu but they aren't very efficient.
you can probably add extra amps later if you really need to.
the NCLs with the inductors in the standard circuit will limit the current and the voltage to appropiate levels.So do you think this is powerful enough for the 30 channels if we base on 30 Cree xp-e 3watts leds? Or would you suggest a high voltage perhaps 12v? I'm just mindful about you saying the NCLs operate better with lower voltages and that I will just be wasting power with high voltages as my leds only need upto about 3.5v max.
just a pullup resistor. the tlcs need to put out a square wave <= 20khz, I assume they can do this. you better check.Finally what additional parts will I need to take in to account the PWM from the open drain of the TLCs?
Just need the standard NCL circuit, running at 12v and definately use a nearby TVS diode with an nominal operating voltage of 12-24v and a let through voltage of 27-32 volts. like this SMA6J24A-TRAlso do I need any current limiting circuits and if so what parts would I need?
Also you need anti static wriststrap connected to earth to use the NCLs and dont take them out of the silver bag until you have your wrist strap on.
I tried a value of 33uH for the inductor, use surface mount for the diodes and caps so you can put them really close to the pins.
In order of component closeness to the chip
1. caps ceramic (smd, if possible)
2 diode
3 inductor
4 resistors
5 caps electrolytics if any
the other thing I have found is that I am using the new Cree XTE leds now, at around 2 bucks each without the aluminium backing.
Last night I sent off a design for my own mcpcb, to mount them, this should cut costs a lot.
They are rated to be very similar in performance to the XPG but 1/3 the cost. so I bought a 100 of them.
No worries about helping, good luck, I just hope you have better luck with the chips than I did. (Luck? It may have been incompetance)
#26773 Powerful Aquarium Lighting
Posted by Magpie on 09 April 2012 - 12:54 PM in General Discussion
They are Junk!
I had my last one running this afternoon, and for one hour it was fine.
I went away and came back in another hour, my workshop was smokey and chip number 5 had gone short circuit. It was only running at 130mA and the chip was running cool. It did actually run very cool for the work it did. I once had it up to 800mA.
I initially had 29 volts, 130mA running into the chip but now I had 450mA running into it (I didn't read the voltage but It would have dropped to about 3-6 volts at a guess).
My current limiting supply had gone into limit mode and I had 450mA running through a breadboard to my chip. The heat in the chip was making the smoke and now it is stuck to the breadboard, I will send a photo, soonish. My smoke alarm didn't go off, it only goes off for normal cooking smells. sigh.
The only excuse I could find for this chip is that the circuit was breadboarded, and you shouldn't do this at High frequencies, but I dont actually believe the breadboarding of this circuit was a problem.
In short the NCL30160 is junk. Dont use it for your own safety.
If you look at the block diagram the short seems to be in the built in voltage regulator.
A timely reminder to take precautions when doing power electronics,
- smoke alarm
- current limited supply
- fuses
- watch closely
#31592 Powerful Aquarium Lighting
Posted by Magpie on 04 July 2012 - 11:11 PM in General Discussion
#31639 Powerful Aquarium Lighting
Posted by Magpie on 05 July 2012 - 11:00 PM in General Discussion
I know I am jumping in a little late here, but I just looked at the picture with the inductors. Aren't the ones on the left actually 33mH instead of 33uH?
I looked at this link coilcraft series
I must admit I don't know.
that's right.The bit in the bottom right corner is the black regulator right?
ps. I changed the logo, it will come out on the silkscreen.
I almost mounted the torroid footprints upside down, that would've been a disaster.
I just sent the gerbers off to seeed studio last night.
If you want I can send you some, I will test them first though.
#32873 Powerful Aquarium Lighting
Posted by Magpie on 29 July 2012 - 01:50 PM in General Discussion
#32871 Powerful Aquarium Lighting
Posted by Magpie on 29 July 2012 - 12:39 PM in General Discussion
#31702 Powerful Aquarium Lighting
Posted by Magpie on 07 July 2012 - 01:54 PM in General Discussion
Thanks for pointing out the missing caps from my BOM, it was also missing R1.
All the caps are just decoupling or filtering caps of 100n 0805 and the Resistor was just a 10k 1206.
I cant believe I made this mistake, It just goes to show how easy it is. I am definitely not a computer.
I haven't gone exhaustively through your list as it seems your not quite decided the best way to go anyway.
As far as boards go I would go the modular approach, so if a board fails you can have spares, x channels per board.
Maybe 3, maybe 8, maybe 16. Design decision.
Also that way you could have some boards at 12 volts some at 5.
Actually on the subject of design decisions, the way just about every project I have worked on has been is that you never design it right first time anyway.
So there is no point trying to perfect the initial design. The moment the first working version comes out, somebody sees things that they hadn't noticed before.
So I think,
- Get something out there,
- Get something out there that isn't impossible to change or fix.
- Keep changing it till you think it's right.
I am writing as I think so the conclusion of what I think you should do is 3 channel boards (wait till I confirm that the design works) start with 5 or 12 volts, (your decision) and see how things go.
As far as 5 or 12 volts for 1 led.
5 volts can be slightly more efficient but, will it always be one led, because you can't easily change it.
If you go 5 volts you may have a noisy supply to the micro, this may or may not be a problem for the Current sensing on the Attiny.
If you go 5 volts you don't need the step up bc847 and it's two resistors. But you do need a different, logic level FET, just like AHellene's circuit.
5v you can use a smaller inductor.
I would use 12 volts but there could be a case for 5v and event a case for 7 volts.
If you want to use my circuit with 12v
just use a different TVS (12v operating voltage).
and remove everything including C3 to L2 reading left to right on the schematic.
Jumper the 24 volt rail to the 12volt rail.
If you want to use my circuit with 5 volts.
just use a different TVS (5v operating voltage).
and remove everything including C3 to U1 reading left to right on the schematic.
Jumper the 24 volt rail to the 12volt and the 5 volt rail.
you don't need the 3 x step up bc847 and short r13 to r15 and open circuit r16 to r18
It gets a bit harder as you may need a clean supply for the micro. I don't know.
Personally I wouldn't bother. It probably would be ok, but I think 12v will give you what you need.
No the netduino can only source less than 1 amp.Do you think this side of the circuit can be powered practically off the netduino
I would power the netduino from my 12v supply. Maybe via a resistor to just take away a bit of the heat.
That is a mistake, it was left there from some other current sense resistor that I had considered, please disregard.Also one of the resistors is marked as a bit wide, is this the foot print or the value and does it matter?
ps. You probably don't want to populate r28,r29, r30, I just put the footprints in for emergencies. I think 100mOhms if the lowest we could go anyway.
Also you don't need R12, this is also a contingency footprint.
You will loose very little running 1 led at 12v vs 1 led at 5. Only really in the higher series resistance of the inductor because you need a bigger inductor.Perhaps even provide a jumper option, where by you can select 5v or 12v and swap out the power supply accordingly?
Just run at 12v.
Steff shield is currently running 3 channels of 7 leds at 24 volts and at about 500mA. (XTE warm white) No heating problems on the shield and very little heat sink on the leds.How many ma are your running your Crees at in this circuit?
I will do 7 leds as well with my 24 volt prototype.
I want to move to 24 - 48. but will probably have to settle on a 24-36v version and 36-48v version, the black regulator doesn't have a wide input range. I just need to change a resistor value to switch between the two variations.
One thing that will work for you is the input circuitry on the Dimmer channels, you should be able to put your square wave straight in.
The input filters use 10k and 0.1uF which gives 166 Hz. If you can give it a pwm above 15KHz then your filtering is done.
BOM is corrected, thanks for finding the errors.
Attached Files
- Steff2 BOM.zip 4.01KB 2 downloads
#31648 Powerful Aquarium Lighting
Posted by Magpie on 06 July 2012 - 10:30 AM in General Discussion
#26758 Powerful Aquarium Lighting
Posted by Magpie on 09 April 2012 - 12:03 AM in General Discussion
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