I'm working on my first major Arduino project and am about ready to move from the breadboard into building a real prototype. I've been researching how to do this, but wanted to know if people had recommended best practices.
The LEDs I'm using are all SSCI-013994, 1 meter each.
They each use 5v, take in one wire for input from the arduino, and a ground. So far, I've only been using one with the arduino's 5v and ground. I'm doing this all on an arduino uno, currently on USB power only.
Is it best to buy an external power supply for this amount? I understand that if one attaches too many LEDs to a too weak power supply they will be too dim. If I should get one, how exactly do I go about finding a power source (or 9 at 5v each) which can attach to a soldered wire on the LED? I bought a 5v power adapter, but am not quite sure how to hook it up directly to wiring. I'm not too experienced at anything involving EE, so would I also need an external ground for all of the strips?
Apologies that these are rather basic questions, but wanted to make sure before I end up electrocuting myself. Thanks in advance for your help.
I can't read the datasheet for the LED strip since it's not in English. I see something about 3.18 Amps. Is that correct for a 1 meter length? (I'm assuming you can read the datasheet?) If each LED strip is 3.18 Amps, multiply that by 9. That's a LOT of current and a fairly big power supply.
I understand that if one attaches too many LEDs to a too weak power supply they will be too dim.
Well yes... If you exceed the power supply's rating the voltage will drop and the LEDs will dim. But, the power supply might also overheat and die. Or if you are lucky and, the power supply is over-current protected, it will shut down without damage. Or, the voltage may drop to the point where the Arduino quits running.
Is it best to buy an external power supply for this amount? I understand that if one attaches too many LEDs to a too weak power supply they will be too dim.
You might damage your power supply too.
These look like WS2812B
If they are:
At full White brightness each LED takes 60ma
60 NeoPixels × 60 mA ÷ 1,000 = 3.6 Amps minimum
Always use a external supply for these, common ground to the controller.
"Before connecting a NeoPixel strip to ANY source of power, we very strongly recommend adding a large capacitor (1000 µF, 6.3V or higher) across the + and – terminals. This prevents the initial onrush of current from damaging the pixels."
Yes, it appears that each requires about 3.18 A. So I'll definitely need to figure out an external power solution.
Thanks for the link LarryD, I'm looking through it now and it's providing a lot of what I'm looking for.
I'm guess best practice would be solder each with wires (using capacitors as well apparently) and then connect either to a unitary power supply or individual 5v power supplies using something like this to make the connection: DC Barrel Jack Adapter - Female - PRT-10288 - SparkFun Electronics
And then take ground wires and signal wires and connect them directly to the arduino board.
Thanks for all the help, I'll read through the Adafruit guide and try to figure out a best overall approach.
Alright, since I'm not experienced with electronics I'd not rather not risk using a potentially dangerous single power supply. Instead I hope to either use a battery pack (likely three AA as shown in that Adafruit post) with each power and ground connected to the wires from the battery pack, and a third wire going back to the arduino. The battery packs appear to be 4.5v and I'm still confirming there will be enough amps.
The other option I'm considering is using individual 5v and soldering them onto the receptors of the strip.
Anything horribly wrong with this plan? Thanks for everyone's help on this.
Hello, I've read a few topics about how and why to common ground LEDs but just wanted to confirm I understand before potentially burning everything out.
Does the shared power supply need a line back to the Arduino for each individual LED or just one for the whole thing?
Three +V terminals and three -V terminals. For testing, I have three LED power wires hooked up to the three + terminals and three grounds hooked up to the corresponding three - terminals. Do I need a ground wire from each of the three - terminals leading back to the arduino? Or just one would work for all? Do different ground ports on the arduino affect anything?
Just one.
The supply has multiple terminals to distribute the current.
One wire with the ability to carry 40Amp woudn't fit under one screw terminal.
Ground terminals (and +V terminals) are just connected together inside the supply.
All grounds on a Arduino are joined. Use the one(s) next to the 5volt pin.
Leo..
Thanks, this worked. However, when I send the same signal to both the one's I'm testing with, the second one (as in, data is transmitted to it second and it is second from the left for power) seems to sparkle white a little in occasional pixels and surges white every so often. Is this a problem with grounding or something else? My power supply is using a capacitor though I haven't yet been able to get the data pin resistors if that could be the error.
Yes it could be the error, as could lack of capacitors.
Not only do you have to have capacitors, there has to be enough of them and in the right physical places.
It seemed to be a problem with the ground wires properly carrying the common ground, though still finalizing some last strips to confirm it's fixed.
One last point I'm wondering is do common ground or power concerns ever affect the arduino's performance for data? Starting getting strange freezes and slows when these power problems started happening, and I've been wondering if the arduino will slow down when trying to send data to a not-properly configured device. More on that problem at a different topic in the LED forum for completeness's sake if relevant: Problem controlling more than 3 LEDs through serial - LEDs and Multiplexing - Arduino Forum
Thanks again for the all the help with this. If people reading this later have questions for similar projects, feel free to send a PM.
Originally, I had all grounds directly the the power supply and one from the supply back to the arduino (no breadboard in this configuration) but we were having some problems with individual strips so moved to the current one.
How long are the wires between supply and LED strips.
0.75mm is the minimum for a short distance.
You might need thicker wire for longer lengths.
Thin/long wires create volt drop, and that could upset the data ground.
Leo..
EthanEdwards:
It seemed to be a problem with the ground wires properly carrying the common ground, though still finalizing some last strips to confirm it's fixed.
One last point I'm wondering is do common ground or power concerns ever affect the arduino's performance for data? Starting getting strange freezes and slows when these power problems started happening, and I've been wondering if the arduino will slow down when trying to send data to a not-properly configured device. More on that problem at a different topic in the LED forum for completeness's sake if relevant: Problem controlling more than 3 LEDs through serial - LEDs and Multiplexing - Arduino Forum
Thanks again for the all the help with this. If people reading this later have questions for similar projects, feel free to send a PM.
Sounds like you have a programming or power problem.
Get your power supply sorted out first.
I do not know how you are currently powering your test rig but its very easy to exceed the supply of an arduino with even a very short strip of those leds.
EthanEdwards:
Thanks, this worked. However, when I send the same signal to both the one's I'm testing with, the second one (as in, data is transmitted to it second and it is second from the left for power) seems to sparkle white a little in occasional pixels and surges white every so often. Is this a problem with grounding or something else? My
It may be damaged, they are difficult to solder , and very sucseptible to heat damage.