HP and DM key Pressure

[Dave Britten]

Got some interesting results. I tested my DM41L and DM42. For each, I did 8 tests using different keys around the keyboard. I did not include the ENTER key in the results, but the Voyager-type models generally require less force than the other keys if pressed in the top half, and the DM42 requires more force due to having the same length lever arm but two spring domes under it.

I only tested force required for the sound and feel of the key click, as I would have needed a more elaborate setup to watch both the calculator display and scale display simultaneously.

DM41L
Mean: 240 g (8.50 oz)
Std Dev: 13.4 g (0.473 oz)

DM42:
Mean: 265 g (9.33 oz)
Std Dev: 27.8 g (0.982 oz)

So there is more variability in the DM42 keyboard, and more force required in general.

And I used my 15C for the statistical calculations and unit conversion.