View Full Version : Make / Brand of PGM Button on Teensy 3.0?

02-05-2013, 11:39 AM
I'm likely the only person who'll ever have to ask this... but who makes the PGM button and what model is it on the Teensy 3.0? I ask because the plastic fell out and now I have to use a sharp pencil, etc to activate the PGM button. Instead, I'd like to buy a new button and cannibize the plastic insert...

Not sure what precipitated the failure, my guess is some shaking during transport to and from work.

02-05-2013, 03:05 PM
It's made by C&K.

Originally, Teensy 1.0 and 2.0 used part number KMR211GLFS.

Several months ago, just before Teensy 3.0, we changed to part KMR432GLFS. The old part had a short button, which was sometimes difficult to press with a finger. Some people had to use their fingernail or they pressed it with a pen or pencil. This new part has a taller button that's much easier to press, with a better tactile feel too.

A few people have knocked their buttons loose. I tried it on a board here. It takes a bit of force, but if you bump the side of the button just right, it will pop out. The same is probably possible on the short button, but because it's so short a lot more force is probably needed, and there's just not much material sticking up to accidentally catch on anything. I've never heard anyone report the short button coming out, but with the taller one, at least a few people have lost the button.

Recently we changed to the KMR421GLFS, to try addressing this issue. It has the same taller button, but the spring inside has less tension. It's rated at 200 grams, rather than 300. It's still too early to tell if the lower spring force makes a difference in practice.

All of these C&K parts are available at Digikey. If you search on their, try leaving off the "LFS" portion of the part number.

On Teensy 3.0, the button connects between the PROG pin and GND. If you wire up another off-board pushbutton, just connect it to those pins. It's quite challenging to desolder a 5 pin surface mount part. The best way to recover might be just adding another off-board button.