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Topic: Resistor for each LED or one for many (for MIDI controller/looper)? (Read 1 time) previous topic - next topic

Grumpy_Mike

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Is that 5v or is it 9v (or does it even matter)?
5V, yes it matters. If you have 9V then it has to be regulated down to 5V. You can do this with the onboard regulator but that limits the current for other stuff to about 500mA, so the extra power supply capacity is wasted unless you get another stand alone regulator.

I avoid breadboard like the plague, it is just so unreliable. Make stuff on strip board.

Paul__B

I was planning on using the little power supply thingy that comes with the breadboards.
Well, if we had even the faintest notion as to what you mean, we would probably be able to comment in a meaningful way.  :smiley-eek:

MountainCraft

Well, if we had even the faintest notion as to what you mean, we would probably be able to comment in a meaningful way.  :smiley-eek:

Sorry.. It's the one that comes with virtually every arduino kit.. I'll see if I can find a picture..

MountainCraft

Very similar to this...  One came with my original arduino kit, and the other came with my Arduino Mega 2560 kit..  Each kit came with a breadboard and these little power supplies..




They plug directly into the breadboard and distribute 3.3v and 5v down the rails on the sides of the breadboard..


MountainCraft

5V, yes it matters. If you have 9V then it has to be regulated down to 5V. You can do this with the onboard regulator but that limits the current for other stuff to about 500mA, so the extra power supply capacity is wasted unless you get another stand alone regulator.
So, I get 3A 5V power supply, and plug it into the little jack on the breadboard power supply module, and power the arduino from the breadboard, or do I ditch that and plug it directly into the arduino and power everything directly from the arudino?  Most of these power supplies recommended for the little regulator module say they operate on 7-12v, so I'm a little confused..  Or are you saying I should bring it in through the little USB jack on the power regulator module?



I avoid breadboard like the plague, it is just so unreliable. Make stuff on strip board.
I can see that, but it's only to be used during the prototyping, then something permanent later.. Thinking of either cutting a Circuit Board on my CNC or having one made later  (Kinda shocked how cheap that service is now)

What is "Strip Board?"

Grumpy_Mike

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but it's only to be used during the prototyping, then something permanent later
Prototyping is exactly when you need a reliable circuit, using bread board leaves you wondering if the circuit design is why it is not working or is it the poor intermittent bread board.

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What is "Strip Board?"
https://en.wikipedia.org/wiki/Stripboard

Those are 0.8A regulators quite useless for what you want.

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It's the one that comes with virtually every arduino kit
You see the "experts" here have never had to have an Arduino Kit, and very few of them use solderless bread board.

MountainCraft

Prototyping is exactly when you need a reliable circuit, using bread board leaves you wondering if the circuit design is why it is not working or is it the poor intermittent bread board.
https://en.wikipedia.org/wiki/Stripboard
Ahh.. we always called that perforated bakelite.. Didn't know it had an official name..


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Those are 0.8A regulators quite useless for what you want.
You see the "experts" here have never had to have an Arduino Kit, and very few of them use solderless bread board.
So how do I power things?  Just plug it into the little jack on the arduino? Isn't that rated at 7-12v too? Or do I buy/make an adapter to power it through the USB port?

Can powering things this way provide all the power I need for the relays and what not?  Or do I need to create a separate 5v rail for all that?  (The relay boards have a separate +5v and gnd  connection that is isolated from the actual signal/logic  jnputs)..

Also, can an external supply and the laptop (while coding) be connected at the same time, or would that mix things and be no bueno?  If it's bad practice, do I have to worry that I will draw too much off the USB port on my laptop?

Also, there is a pin labeled 5v on the arduino..  Is this a point for being supplied 5v or to supply 5v to other things.. If the latter, what is the current limit on what can be run from that pin?

Grumpy_Mike

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So how do I power things?
Get a 5V power supply and connect it to the 5V pin on the Arduino and also to everything else that needs 5V. There are plenty of 5V supplies around for charging.
You can get a power jack to screw terminals if the physical aspect bothers you.

https://cpc.farnell.com/clever-little-box/clb-jl-52/dc-barrel-plug-2-1x5-5mm-screw/dp/CN19644

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we always called that perforated bakelite.
But it is not bakerlite, the cheaper stuff is simply SRBP   ( Synthetic Resin Bonded Paper ). You can get it made from fiber glass sheets as well but they are more expensive.

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Also, can an external supply and the laptop (while coding) be connected at the same time
The purest would say no but i practice it does not cause any feedback problems that I have come across.

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The relay boards have a separate +5v and gnd  connection that is isolated from the actual signal/logic  jnputs
In fact they are not isolated despite having an opto isolator on them. You use that extra 5V to insert extra decoupling like the last circuit on this page:- http://www.thebox.myzen.co.uk/Tutorial/De-coupling.html

Wawa

So, I get 3A 5V power supply, and plug it into the little jack on the breadboard power supply module, and power the arduino from the breadboard

or do I ditch that and plug it directly into the arduino and power everything directly from the arudino?

What is "Strip Board?"
Can't do that. That DC socket is feeding the 5volt regulator on that board, and needs at least 6volt for the regulator to make a stable 5volt. A 7.5volt or so supply would be ok, but note that that regulator has almost no heatsink. It can power the Nano, and a few sensors, but nothing else.

Powering everything from the Nano is almost the same, except for the 3.3volt output (if needed).

Google "Veroboard"
Leo..


Paul__B

Also, there is a pin labelled 5v on the Arduino..  Is this a point for being supplied 5v or to supply 5v to other things.. If the latter, what is the current limit on what can be run from that pin?
Piss all!  (To use Mike's terminology. :smiley-eek: )

Yes, to clarify, that is where you feed power into the Arduino, given that you have a regulated power supply at 5 V.  You can also use the USB jack (and then take 5 V from the 5V pin) but it connects via a polyfuse rated about 500 mA.  In general, use the 5V pin to power the Arduino from your 5 V supply and also connect that supply to everything else in parallel, that requires 5 V.

Consider the "Vin" pin and the (2.1 mm pin) "barrel jack" on the Arduino and the breadboard adapter, as of negligible use.  Maybe a couple of indicator LEDs.

The USB socket on the breadboard adapter is actually more useful for feeding 5 V directly into it, but you need a male-male adapter cable to do it.

MountainCraft

Piss all!  (To use Mike's terminology. :smiley-eek: )

Yes, to clarify, that is where you feed power into the Arduino, given that you have a regulated power supply at 5 V.  You can also use the USB jack (and then take 5 V from the 5V pin) but it connects via a polyfuse rated about 500 mA.  In general, use the 5V pin to power the Arduino from your 5 V supply and also connect that supply to everything else in parallel, that requires 5 V.

Consider the "Vin" pin and the (2.1 mm pin) "barrel jack" on the Arduino and the breadboard adapter, as of negligible use.  Maybe a couple of indicator LEDs.

The USB socket on the breadboard adapter is actually more useful for feeding 5 V directly into it, but you need a male-male adapter cable to do it.

Thanks! Exactly the answer I was looking for!

MountainCraft

The purest would say no but i practice it does not cause any feedback problems that I have come across.
In fact they are not isolated despite having an opto isolator on them. You use that extra 5V to insert extra decoupling like the last circuit on this page:- http://www.thebox.myzen.co.uk/Tutorial/De-coupling.html
I was talking about the relays being isolated.. ie that they do not draw any power from the arduino to operate, only the logic signal, with the operating power being provided via a separate 5v input to the relay boards..

That being said, you bring up a good point about noise rejection in the whole project...  First of all, is noise rejection required across the relay coils, or is this something that is primarily for discreet components?

As a general rule, should I plan to put a 47uf electrolytic across the output of the power adapter where it supplies power to the entire project?

As for as the individual caps, do these go across the 5v (or 3.3v) to ground whenever supplied to a discreet device? Or is it for the signal/logic paths? (or both)

Thanks,
Mark

MountainCraft

The USB socket on the breadboard adapter is actually more useful for feeding 5 V directly into it, but you need a male-male adapter cable to do it.

Can the full 3A of the power adapter be fed into the system via this port?  Or is it fused at 500ma too?


If not, is there a female USB receptacle available anywhere that is prewired (has a pigtail coming out)? Having trouble finding that..

The power adapter I just ordered has a micro USB (male) connector.. I found some adapters to standard USB (female to male), but I guess if worse comes to worst, I can always just cut the connector off of the thing and hard wire it..  Would be nice to be able to just 'unplug' it from the system though..

Eventually, at some point I will need to be able to power it off of a pedal board supply, so some sort of receptacle or barrel connector will be needed..

Thanks,
Mark

Grumpy_Mike

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I was talking about the relays being isolated.. ie that they do not draw any power from the arduino to operate, only the logic signal, with the operating power being provided via a separate 5v input to the relay boards.
Yes so was I.

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First of all, is noise rejection required across the relay coils,
Yes, mainly a reverse polarity diode to stop back EMF from the coil when it turns off.

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As a general rule, should I plan to put a 47uf electrolytic across the output of the power adapter where it supplies power to the entire project?
Yes but bigger if you are drawing more current.

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As for as the individual caps, do these go across the 5v (or 3.3v) to ground whenever supplied to a discreet device?
What do you mean by discreet device? It is a yes for active components like integrated circuits. No for real discreet devices which mean transistors and the like.

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Can the full 3A of the power adapter be fed into the system via this port?
No there is a resetable fuse in that line at about 500mA.




MountainCraft

Yes so was I.
Yes, mainly a reverse polarity diode to stop back EMF from the coil when it turns off.
Yes but bigger if you are drawing more current.


Okay, I'll come back to this when the power supply comes and I start hooking it all up..

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What do you mean by discreet device? It is a yes for active components like integrated circuits. No for real discreet devices which mean transistors and the like.

Yeah, I was referring to everything not electro mechanical or tube..  ICs and transistors alike.. What is a better term to encompass everything non electromechanical or tube, 'solid state?' 'semi-conductor?'

But I got an even better answer than I was looking for.. :)

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