I have a functioning prototype, now what?

This is my first Arduino project. I THINK, that it is a pretty straight forward LED project (see attachments).

The prototype is based on an UNO board but I think I would like to use a smaller form factor as a matter of convenience and cost. Perhaps a NANO EVERY?

It is a 1m LED strip so I am using a 5v/2A AC/DC power adapter which brings me to one of my questions. I have read that 'bad mojo' can happen if the board is supplied power from both an external power source AND a data/charge connection to the computer. How is that addressed in completed projects?

The prototype works as expected. But now what? how do I get the complete circuit into a smaller form factor? Ideally everything would be enclosed in a small project box with three connections Data/Power/LED. I don't think solutions use full size breadboards and n-number of jumper wires. I'm assuming I have to use some sort of home built circuit board? In general, i'm not sure where to start?

mike

ArduinoLED.JPG

ArduinoLED.JPG

I suggest to replace the breadboard with a solder-type prototyping board, which will be much more reliable, and the Uno with an Arduino Pro Mini, or something even smaller, which can be mounted directly on the prototyping board. Look around!

Example prototyping boards Adafruit Perma-Proto Quarter-sized Breadboard PCB - Single : ID 1608 : $2.95 : Adafruit Industries, Unique & fun DIY electronics and kits or Adafruit Perma-Proto Half-sized Breadboard PCB - Single : ID 1609 : $4.50 : Adafruit Industries, Unique & fun DIY electronics and kits

You can power the Arduino from the LED power supply using a 5V step down module (connected to the Arduino 5V pin).

I'm assuming you only want to make one of these so that designing and having a custom PCB fabricated would be excessive (and prone to errors and added cost if you are new to PCB design).

I make my finished products on stripboard (veroboard) using an Atmega 328 chip working at 8MHz with the internal oscillator.

...R

Connect it up with a Promini as the controller.
Use FTDI Basic module to load the code, then disconnect it for the redeployment.
Hardly a need for a PCB here.

darksaber:
I have read that 'bad mojo' can happen if the board is supplied power from both an external power source AND a data/charge connection to the computer. How is that addressed in completed projects?

The safest way would be to cut the red wire (+5V) in an old USB cable. Then the PC will be safe from the voltage you put on the +5V pin.

If you use an Arduino UNO and provide power with the power jack or Vin pin you don't have to worry. The USB power is automatically disconnected when the voltage going into the 5V regulator is high enough to power the board (6.6V).

I eventually found the pictures of one of my projects.

ControllerDSCF4230sml.png

...R

I looked at the Nano schematic to confirm because I am doing a similar project. The Nano has a diode from VUSB to +5, they call it "+5V auto selector". The anode is connected to VUSB, so if power is applied (for example if +5V is shared with a LED strip, powered by a honking big 5V supply) the USB connection will still operate normally for programming and serial control.

As suggested above, a Pro Micro or as I suggest, a Nano, can do the whole job, there is no need for a custom board. Both are very small.

2A sounds a little under-rated for some 1M strips. Did you actually measure the maximum current?

Mini is the small Uno. Nano Every is different.

and a project with photos GitHub - JAndrassy/KitchenTimerClock: A kitchen timer with clock.


Thanks to everyone for the feedback. Plenty to think about here.

@aarg

aarg:
I looked at the Nano schematic to confirm because I am doing a similar project. The Nano has a diode from VUSB to +5, they call it "+5V auto selector". The anode is connected to VUSB, so if power is applied (for example if +5V is shared with a LED strip, powered by a honking big 5V supply) the USB connection will still operate normally for programming and serial control.

As suggested above, a Pro Micro or as I suggest, a Nano, can do the whole job, there is no need for a custom board. Both are very small.

2A sounds a little under-rated for some 1M strips. Did you actually measure the maximum current?

If I understand your comments correctly, I could have both a microUSB and external power connected and it would NOT damage the board? This would allow me to reprogram the NANO if needed?

I am leaning toward the NANO
2A is a little low at full power. I am running them just under 40% which puts me right at 1.12A. I think I could go as high as 70% but I don't think I will need to go that high.

jremington:
I'm assuming you only want to make one of these so that designing and having a custom PCB fabricated would be excessive (and prone to errors and added cost if you are new to PCB design).

$2 is expensive?

Learning to use the free Eagle cad program and getting five 2-sided PC boards for $2 has pretty much eliminated perfboards here.

Here's a quick project I did last year.

SteveMann:
$2 is expensive?

You will note that I said "excessive" and not "expensive"

I have to attach some value to the time it would take me (probably a few days) to learn Eagle (or an equivalent) and I have no confidence that my first design would be correct. And after all that I might never need to use any of this learning again.

...R

darksaber:
If I understand your comments correctly, I could have both a microUSB and external power connected and it would NOT damage the board? This would allow me to reprogram the NANO if needed?

It actually has nothing to do with damage to the board. The concern relates to "back-feeding" power from the external supply into the USB system of the PC if the external 5 V is significantly higher. And this is only a concern to the UNO and Mega 3560. The Nano has no problem at all.

When you say

darksaber:
How is that addressed in completed projects?

the answer is that in a completed project, you generally do not operate it while connected to a PC.

Yes, if you need USB, the Nano is always the "go-to" for a serious project, and the Pro Mini if you do not need USB.

Notwithstanding Robin2's craft, it is not worth "re-inventing the wheel" and pulling together the separate parts given the price of Nano (and Pro Min) clones which are more compact that the DIP version of the ATmega328. If you get them without the header pins soldered, you just solder your connections directly to the board.

If you did wish to make a PCB for something, you use the header pins to attach the Nano clone as a "daughterboard" to your own PCB.

Paul__B:
Notwithstanding Robin2's craft, it is not worth "re-inventing the wheel" and pulling together the separate parts given the price of Nano (and Pro Min) clones which are more compact that the DIP version of the ATmega328.

According to the Product page a nano measures 18 x 45 mm and according to my ruler an Atmega 328 measures 9 x 35mm

I respect (though I do not share) your preference for using nanos, but let's keep the facts correct.

...R

And there's the original Ardweeny, same size as the DIP.
Plug an FTDI Basic (or clone) on for programming it, them embed it in your project.


Or my Atmega1284P version if you need more IO, or a 2nd hardware serial port.

Robin2:
I respect (though I do not share) your preference for using nanos, but let's keep the facts correct.

The facts are that the Nano - or Pro Mini - already includes all the peripheral bits and pieces that are necessary on your perfboard.

Just comparing apples with apples. :roll_eyes:

Paul__B:
The facts are that the Nano - or Pro Mini - already includes all the peripheral bits and pieces that are necessary on your perfboard.

Just comparing apples with apples. :roll_eyes:

Yes, I'm using the Nano, and I can't imagine any reason for manufacturing a custom board for this purpose. I have soldered only the ICSP connector pins to it, since it has ground, +5V, and two digital pins. So the strip connector mates one to one with the "back" 3 pins of the 6 pin header. This makes it physically trivial to build. I solder the strip wires (actually the connector harness) to a 3 pin female. That just plugs right on to the Nano board. The other end has the USB, which is also physically convenient.

Paul__B:
The facts are that the Nano - or Pro Mini - already includes all the peripheral bits and pieces that are necessary on your perfboard.

I don't see it as simple as that. Given that I will need the perf board in any case the only extra parts I need are 3 small capacitors, a resistor and a piece of header pin for programming.

But, hey, there is room in the world for different approaches. If not, Apple would never sell a single thing :slight_smile:

...R

Paul__B:
The facts are that the Nano - or Pro Mini - already includes all the peripheral bits and pieces that are necessary on your perfboard.

Just comparing apples with apples. :roll_eyes:

Hi guys! It really doesn't make sense to compare Nano or Pro Mini, because they are almost the same. But if you need USB - then Nano is better to use. You know, I understand you, there are problems when you need a very small detail. I had a situation, when I was developing and testing planes parts. We had to create ultra-small chips of the aircraft control system in two copies for testing. We didn't really need the money, but we couldn't find anyone to help us. All companies did not want to make these chips, because it is not profitable for them to make products in just two copies. Then my friend, who works in the field of nanotechnology, advised me guys, who are engaged in rapid prototyping https://www.3erp.com/. This is a very progressive sphere, that allows you to quickly create the necessary detail. The chips were created. And our plane flies perfectly :slight_smile: