I'm currently designing a custom PCB on which an UNO R4 Wifi will be mounted “upside down” onto two rows of header pins. If the LED array was on the bottom of the Arduino board’s PCB the LED array could potentially perform a useful function if it was visible via a transparent “window” in which ever enclosure I chose to use. Otherwise, the LED Array is a resource for which there may be few uses. Same comment applies to the UNO Q board.
Why not put the LED array un the underside of the PCB ?
It would cost more.
Why mount the board upside down ?
It makes a quick and simple interface to the components on my board, rather than adding dupont wires - which are often unreliable. The enclosure can also be a little thinner as it won’t have to accommodate the bend radius required by dupont trype ribbon cables.
More by what percentage ? It’s not unusual to have to accept an additional cost for increased functionality.
Take the socket connectors off the R4 and replace them with pins on the bottom and mount it the right way up
If the LEDs were on the bottom then they would be in the wrong place for most use cases
You are the odd one out here
Odd maybe, supplying the board without the socket connectors soldered in place might have wider appeal to other “odd folks”… and lower the cost perhaps ?
Doesn't matter. You bought the board knowing that the LEDs were useless, so will others.
Hi @anoracknophobia2. You might be interested in the creative solution @PickyBiker used of adding a cutout window in the PCB of a custom UNO R4 WiFi shield so that it does not block visibility of the matrix.
You can see the shield at 1:27 in this video:
https://youtu.be/J7KQ1WsRick?si=wIlAs2kqVBzfHtoo&t=87
Obviously that wouldn't solve your problem if you proceed with the plan to have the bottom of the UNO R4 WiFi board facing the visible side of the enclosure. However, it is likely that you are free to mount the assembly in either orientation and the real visibility is in the custom PCB covering the matrix, rather than the direction the matrix is facing within the enclosure.
Cutting an aperture in the PCB isn’t viable for my project as I’m mounting several SMDs in the space between the two rows of connectors.
Bite the bullet and replace the sockets with pins on the bottom of the board
I’m not actually planning to utilise the LED array for this particular project so I’ll pass on that suggestion.
It's a pity that Arduino don't offer more of their boards without headers.
I agree.
I’m currently considering using an Uno R4 WiFi with a custom PCB with header pins which will mate with the “upside down” Uno - hence the LEDs won’t ever be visible.
Removing the existing sockets will be a chore and might damage the Uno board….
( I have many years of experience with a soldering Iron and desoldering tools ).
To answer your question, the cost would about double. But that is not the real question, which is how many of these boards would need to be sold to recover the cost?
Yes the LEDs are (as they are) useless and not relevant to my project as they will never be visible … I plan to mount the UnoR4 WiFi board “upside down” - mating with two rows of header pins.
If the LEDs were on the underside they might have been useful under a few diagnostic circumstances or even made visible to the outside world via a transparent window in the proposed enclosure.
You could work on your desoldering skills and then you’d have more mounting options.
Ha ha … I’ve been soldering and desoldering Though Hole and Surface Mount components for well over half a Century so I’d guess I’ve moved on from Grass Hopper status.
I’d guess this Uno board has plated through holes too which can be difficult, requiring some care and perhaps a destructive ( to the socket ) technique.
As my current project has no use for the on-board LED Array I won’t bother and will proceed with mounting the Uno board “upside down” onto two rows of Header pins on my Custom PCB.
The original post in this thread was mostly motivated by my thoughts of “ what a waste of so many LEDs “ .
I get some of them from my china supplier without pins. Some have dual rows for pins so there is two of each. They generally are less expensive and I have had no quality problems.
Yes, it's nice when you can do that. I was talking about the genuine Arduino boards of which relatively few are available sans headers.