deskthority

While playing with my electronics gadgets today, I became curious about how much power does my HHKB take, compared to the other keyboards. So I did some measurements (approximate). I was really surprised how much does the HHKB take. Not that it makes too much of a difference in today's world, but for people running laptops on batteries it might. Also, I don't have any keyboard with atmega32u4, but I would guess that those would take 15-20mA without backlight.

HHKB Pro 2: 135mA

SPRiT's 60% build with backlight (actually only 50 LEDs, there could be about 10-12 more):
- no backlight: 16mA
- each level of backlighting adds almost exactly 10mA, to a maximum of about 120mA.

Now my older measurements:
Poker II:
- no backlight: 20mA
- with backlight, from the dimmest to the brightest: 22mA, 25mA, 32mA, 43mA, 65mA, 105mA, 190mA

KBT Pure (no backlight):
vanilla: 5.7mA, CapsLock LED on: 7.3mA, 4 LEDs under RShift, RAlt, RGUI, RCtrl on: 27mA

Very interesting issue I have never thought about. I guess we could add that data to the wiki entries also. You sure that HHKB Pro 2 measurement is right? Must be a power guzzler for such a small board!

The HHKB's problem lies in its USB hub. Nice enough idea, but troubling when it comes to juice. Especially for such a natural travel keyboard!

Plenty more numbers here:

http://deskthority.net/keyboards-f2/pow ... ilit=power

Yeah, I knew I'd seen this topic here before somewhere.

Ah sorry guys, I know I should have searched the forum before posting.

And yea, I suppose it's the hub for the HHKB - I've also measured a random USB hub that I had lying around and that also took 95mA by itself.

No harm in posting new threads. Not everyone sees, let alone remembers, everything! Besides, I still need to test my boards. What gear are you using?

Just a multimeter and what's essentially a cut USB cable: https://flabbergast.github.io/posts/usb-tester/

EDIT: Oh yea, and Teensy 2.0 with Soarer's converter firmware is about 27mA.