I'm having a big problem in the design of my shield. It uses a lot of thru-hole parts and I can't seem to solve how to make it attach to the Arduino without some pins touching the USB connector on the Arduino.
Regular header pins and the nifty little "shield stacking headers" (http://www.adafruit.com/index.php?main_page=product_info&cPath=17&products_id=85) aren't tall enough to clear the TH pins. I've found these (http://www.mouser.com/ProductDetail/3M/926381-01-36-I/?qs=iX%252bANPjrAyiutBzxrZfuFw%3d%3d), but no one has them in stock and I don't want to order 200 of them at $3 each.
Does anyone know of a long header, preferably like the shield stacking headers, that has .6-.7 inch (15.24-17.78 mm) long pins? It wold be nice if they weren't half the cost of the shield too. ;)
How about changing up the design a bit. Nothing says an arduino shield's PCB has to be the same dimensions as the arduino. If you consider the USB header the front of the board then have your shield hang off the back end more. Sometimes that small PCB size is just too limited to hold everything you want to get onto it.
Another option would be to mask over the solder joints that sit above the USB header. Many high end electronics have to use a strip of electric tape or hard plastic over some items to avoid shorts between said items and solder joints.
The pins don't have to bottom out on the headers to make a good connection. For the most part the plastic bases of the header pins should offer enough clearance. That is if extra care is taken to keep the solder joints neat and trimmed.
If you are worried about the shield actually not fitting because of the usb connector, then i don't know.
But if you are only worried about shorts, wear long pants. ;D
Just kidding, what you should use is tape on the usb connector.
Samtec SSQ series with lead style 4 has pins that are 14.73mm long. For small quantities, they'll send you samples. For larger quantities you should probably redesign your board not to put any through-holE components above the USB connector, or switch to a base Arduino board with a mini-B connector instead of the full-sized one.
"thru-hold". Ooops! :)
I think I'm going to move parts around so there are no pins over the USB port. If I were to place a durable layer over the pins by the USB, it would raise up the board way too much for standard headers. They won't mate properly with the Arduino and would be flaky. And long headers would help at a higher cost, but it still doesn't solve for the header sockets for further stacking. But if I get rid of pins around the USB port, I can get away with all standard parts that are readily available.
I can spend time to make it right once and for all, or spend money to work around it for every board. ;)
Thanks for the suggestions!
I'm going to move parts around so there are no pins over the USB port
Be careful; the exact location of the USB port is not necessarily the same on all Arduino versions and clones...