Mounting hardware for Arduino boards

I surely cannot be the only Arduino user who has come across this problem.

I want to securely mount an Arduino board inside an enclosure.

I cannot understand the thought processes of the people who laid out the Arduino boards- (1) the mounting holes, at least on the UNO, are very, very close to the edges of the board- mechanically dubious, (2) the holes make it impossible to put nuts or screw heads (for 4-40 or M3 sizes) on the top side of the board , as there is not enough room between the holes and adjacent components- particularly headers, (3) the PCB hole diameters are 3mm, whereas almost all of the industry standard PCB mounting hardware I can find requires 4mm diameter holes in the PCBs. Why? Why? Why?

The only hardware I can find is RS components 220-771 etc, which are adhesive backed (not so mechanically reliable), but at least requires 3mm diameter holes in the PCBs.

Does anyone know of alternative mechanical mounting hardware??

Thank you

You might move from an Uno to something that can be soldered to a perf-board. Most perf-boards have standard sized mounting holes at regular places. I tend to like the Adafruit perma-proto boards. For example, here is a combo pack of the 3 main sizes: Adafruit Perma-Proto Super Pack! : ID 591 : $34.95 : Adafruit Industries, Unique & fun DIY electronics and kits, plus there are 2 other perma-proto boards that fit inside the small and standard sized Altoids mint tins.

In terms of chips, you can buy various chips made for proto-boards. I just picked up a Pololu A-Star 32U4 LV (Pololu - A-Star 32U4 Mini LV). The A-Star series was just announced at pololu, and it uses an ATmega32u4, which is the same chip that is in the Leonardo (Uno uses ATmega328p). There was a sale that expires today (July 31st) that had them for 1/2 off (code ASTAR50 if you act quickly). I went for this because it had a built-in step-up/step-down voltage regulator, USB serial support, and the i2c pins are on the outside. If you don't need those things, you can get Arduino Pro Mini clone boards fairly cheaply.

If you want to buy an official licensed board, the Arduino shop has the Micro for sale (the Micro has the ATmega32u4 in it, unfortunately the Arduino store is sold out of the ATmega328p boards that aren't development kits like the UNO): http://store.arduino.cc/product/A000093

gerrymcc:
I surely cannot be the only Arduino user who has come across this problem.

I want to securely mount an Arduino board inside an enclosure.

I cannot understand the thought processes of the people who laid out the Arduino boards- (1) the mounting holes, at least on the UNO, are very, very close to the edges of the board- mechanically dubious, (2) the holes make it impossible to put nuts or screw heads (for 4-40 or M3 sizes) on the top side of the board , as there is not enough room between the holes and adjacent components- particularly headers, (3) the PCB hole diameters are 3mm, whereas almost all of the industry standard PCB mounting hardware I can find requires 4mm diameter holes in the PCBs. Why? Why? Why?

The only hardware I can find is RS components 220-771 etc, which are adhesive backed (not so mechanically reliable), but at least requires 3mm diameter holes in the PCBs.

Does anyone know of alternative mechanical mounting hardware??

Thank you

Build your own pcb with Arduino mini pro on it.

gerrymcc:
I cannot understand the thought processes of the people who laid out the Arduino boards-

They were thinking these would be prototype boards that never got mounted anywhere. Perhaps the the holes were added at the last minute. Interestingly, they are in the same place as the very original Arduino. So no future thought has been given to them.

[Edit: Correction. The Uno did get a slight modification. A hole was added or moved.]

Using stand-offs, I have successfully mounted Uno boards in enclosures (while waiting for my custom board to be finished.)

I have never had a big rip thru its hole location. Fiberglass is pretty tough stuff.