How to power an LED stripe and the Arduino Nano with the same power source

Hi folks,

I'm working on turning the IKEA toy kitchen (Duktig) into an Arduino-powered Christmas present. :wink: The kitchen will be able to play sounds and turn on lights.

I came up with the following breadboard. Could you please tell me whether this is correct? I'm mainly concerned about whether powering the Arduino Nano and the LED stripe (its an Adafruit Neo Pixel stripe with 60 LEDs/meter) is correct.

If you need more information, please let me know.

Matthias

It is hard to tell if it will work without a proper diagram, however you have some things missing. You need a large capacitor across the power input to the strip, at least 1000uF.
You also need a resistor in seriese with the strip’s data line, between 330R and 510R.

You do not say how many LEDs their actually are in that strip. They can take up to 60mA for each LED so the power supply needs a good capacity if it is going to last long.

Hi @Grumpy_Mike,

thanks for your reply.

Here's the diagram: https://github.com/Scaronthesky/smart-kids-kitchen/blob/master/docs/SmartKidsKitchenBreadboard.fzz

Some follow-up questions:

  1. So it's basically possible to power the Arduino and the LED stripe with the same power source?

  2. Why do I need the capacitor and the resistor? EDIT: What type of capacitor (polarized / not polarized) would I need?

  3. The LED strip has 60 LEDs/Meter and is just one meter long. I'm planning to cut the strip into several parts to install them in the oven, the microwave and as a kitchen light. The separate parts will be connected by normal wires.

Thx!

No a schematic not a .fzz file.

  1. yes you can
  2. you ca not get none polarised capacitors of that value so you have no choice. The capacitor stops interference from the strip and stabilises the supply voltage. The resistor stops reflections and protects the input.

I attached a schematic and a bread board based upon your suggestions. I'm new to electronics so I find the bread board diagramm easier to understand.

Is that what you meant?



Your 100uF cap is not connected correctly. It should go across 5V and ground, close to the led strip.

Your "schematic" is an unfinished mess, you should look at other schematics to get a feel for how they should be layed out.

More like this?

Your "schematic" is an unfinished mess,

Wow that was kind.

scaronthesky:
I came up with the following breadboard. Could you please tell me whether this is correct?

Not without a proper circuit diagram. So far it's been Fritzies and spaghetti that I've seen from you so sorry, no go. That's too impossible to figure out. Even a rough hand-drawn circuit diagram is better, or if you want to be more serious in this hobby get a proper circuit diagram program such as KiCAD or EagleCAD.

Some obvious errors in that spaghetti image:

  • The power source has both + and - connected to GND. That's going to smoke.
  • Same for the Neopixel and SD card adapter: Vcc and GND connected. But it won't get powered anyway so at least no smoke from that.
  • C1 has only one pin connected.
  • GND is connected to A7.
  • one of the pots is connected to the RESET.
    I stopped looking. This is enough to declare it an unfixable mess.

And to take the question a bit more literal: a protoboard is not suitable for anything that has to resemble permanency. If you build your toy gift with a protoboard it'll have fallen apart before you're done packing.

I think we are not being encouraging enough to a beginner.

The cap is connected ok now.

Fritzing's schematic editor is ok. Not great, but ok, and better than breadboard view for anything more complex than what you have now.

Schematics are actually easier to understand than breadboard view, or they should be if they have been done well. Schematics can dispense with unnecessary detail, such as exactly where in a breadboard a component has been connected. Instead, because they are more clearly and logically laid out, there is room for important information like component values and part numbers.

PaulRB:
I think we are not being encouraging enough to a beginner.

Thank you for realizing this. I'm actually a bit appalled by the language in this forum. I thought the Arduino project was about learning electronics and not bashing newbies. I included a Fritzing bread board because that is what I saw in the tutorials.

Anyway, here's my attempt at a schematic.

Anyway, here's my attempt at a schematic.

Fantastic, that is 1000% better. :slight_smile:

I'm actually a bit appalled by the language in this forum. I thought the Arduino project was about learning electronics and not bashing newbies.

It is and look what you have learned, it's great. You are now in a position to communicate your ideas to others and ask for help when you need it.

I included a Fritzing bread board because that is what I saw in the tutorials.

That is the problem with a lot of tutorials you see. People think they are being kind showing physical layout diagrams where in fact they just retard the learning process. We have people coming on here and saying "I have done all the tutorials but I don't think I have learned anything". And they havn't, they have just gone through the motions of plugging this wire here and that wire there without understanding the circuit they are making.
You are well on your way now, that looks fine.

For something you build into a toy you need to make it on strip board. Get some pin strips and sockets and solder it up.

Schematic looks basically OK except for the speaker part - I assume this is a sound module that's powered separately, not just a speaker as drawn?

The LED strip has its built-in driver I assume?

Those Fritzings are like a cancer. It's all over the place. The other day I was looking for some schematics and it took me ages to find a readable circuit diagram... all Fritzy images. Sure it looks pretty but it's not a way to build a circuit beyond two or three LEDs.

Your schematic is pretty readable:

The protoboards aka stripboards aka perfboards we're talking about looks like this:

The end result can look a bit messy, though. That's what always happens to me... Step 1 is build your circuit on solderless breadboard, then when it's correct you solder it on perfboard. I'm using the PCB layout function of KiCAD big time to sort out all connections and where to place stuff before starting to build my protoboards.

The LED strip has its built-in driver I assume?

well he did say in the original post.

Arduino Nano and the LED stripe (its an Adafruit Neo Pixel stripe

I assume this is a sound module that's powered separately, not just a speaker as drawn?

But what he has drawn will still work.

This is strip board Stripboard - Wikipedia

Alright. I have learnt you don't like "frizzies". ;D

I already have a strip board. I'm just using the bread board to hook up the Arduino so I can start coding and testing.

The speaker is an active speaker with an external power source (not shown in the schematic), so the speaker symbol is merely just a representation of the 3.5mm jack. The resistor should reduce the volume of the sound.

The LEDs can be controlled individually, yes.

so the speaker symbol is merely just a representation of the 3.5mm jack.

So it should be drawn as a box and labeled as such instead of using a symbol incorrectly. That is one of the things we don't like about Fritzing is that people just substitute symbols and make no mention of it. With a pen drawn schematic if you don't know a symbol, then you just draw a box.

The resistor should reduce the volume of the sound.

No it won't. That would only reduce the volume if the input impedance of your amplifier was in the same order of magnitude as the resistor. What you need to reduce the volume is a potential divider made with a pot or two resistors.

Also if that audio output is a PWM signal then I would put a restoration filter between the pin and the input to the amplifier. A 1K5 series resistor and a 10nF capacitor to ground should clean things up, then I would also put a capacitor from the wiper of your pot to the input of your speaker system to keep DC out of the circuit.
Like this
PWM audio out.jpg