>>181
And you estimates confirm PP3 is cheaper too:
I really don't want to be mean to you but seriously what the fuck man.
Power equals voltage * current.
Energy equals power * time.
Energy equals voltage * current * time.
Voltage is measured in volts (V).
Current is measured in amps (A).
Current * time is measured in Ampere-hour ("Ah"), where 1 Ah is the amount of charge that will have flown at the rate of 1 A during one hour. It turns out to be equal to 1 Ah = (3600 s)(1 A) = 3600 C. (C = coulombs)
Oh but then multiplying ampere-hour by volts gives you the amount of energy since energy = voltage * (current * time).
The energy units will be Watt-hour ("Wh"), here 1 Wh is the energy given by a flow of 1 W during one hour; that is, 1 Wh = (3600 s)(1 W) = 3600 J.
The reason people use Ah and Wh instead of Joules is mainly because it allows to easily estimate for how long a battery will hold. For example, if a battery holds an energy of 6 Wh and it is drained at the rate of 2 W, the amount of time it will last is simply 6 Wh / 2 W = 3 h. Neat huh?
Recyko AA 4-pack, 1.2V, 2050mAh, 8 USD
Each cell provides a voltage of 1.1 V (lower bound estimate) and can let out 2.050 Ah of charge. Therefore the amount of energy is (1.1 V)(2.050 Ah) = 2.255 Wh.
The pack contains 4 cells and costs 8 USD, therefore the number of USD per Wh is (8 USD)/((2.255 Wh/cell)(4 cells)) = 0.89 USD/Wh.
Recyko PP3 3-pack, 9V, 155mAh, 22 USD
Each cell provides a voltage of 9 V (upper bound estimate, let's be really optimistic) and can let out 0.155 Ah of charge. Therefore the amount of energy is (9 V)(0.155 Ah) = 1.395 Wh (that is, a bit more than half of a
single AA cell).
The pack contains 3 cells and costs 22 USD, therefore the number of USD per Wh is (22 USD)/((1.395 Wh/cell)(3 cells)) = 5.26 USD/Wh.
As you can see, PP3 cells cost 6x more for the same amount of energy.
[comparing pricing, etc.]
You're forgetting one very important thing; that single PP3 will last very little time.
Let's suppose that our little device consumes 3W.
With a single PP3, the amount of time the battery will last is 1.395 Wh / 3W =
0.47h. That's right,
less than half a fucking hour. If you put in two of them you're almost up to one hour.
What about those six AAs? Well you have (2.255 Wh/cell)(6 cells) / 3W = (13.53 Wh) / 3W =
4.5h.
With two batches of AAs (i.e. 12 cells) you can go the entire day, but with PP3s you would need
twenty of them to go for the same amount of time (and you would interrupt what you're doing every 28 minutes to swap batteries). Twenty batteries that are 6x more expensive, that is.
Your latch system is indeed amazing. Break one, you have 3 to go. Break another one, the monitor still stands.
In order for the monitor to fall,
both diagonal LCD support rods would need to get detached from the main piece (keyboard),
and the latch that holds the green rods and blue rods in the diagram would need to fail,
and the entire thing would need to be tilted in a specific direction for the LCD to slide off (a pretty big angle too if you consider the steel-on-steel hinge friction).
http://www.humblehacker.com/keyboard/
Oh god no,
please don't separate the alpha keys. What's wrong with the Noppoo Choc Mini layout? Besides, since the layout is ortholinear you can just swap the caps and reprogram the μC if you want a more, um, unorthodox layout.
1 Ethernet 1Gb/s? [do you want 2? I always wanted to 2, but USB can be used]
Yeah, too much extra complexity for not that much usefulness. Just use USB if needed.
*1 CompactFlash slot [or internal SWAP and temp files, unless you want/know a smaller GPIO standard/protocol for the HDD; inboard SATA?]
To be honest I find this to be a waste of time and effort. SD cards are pretty much expendable these days so you might as well just add an extra internal SD card slot for swap and all that and just use it til it dies. It shouldn't be that bad provided the computer has enough RAM and doesn't need to swap constantly. Also remember that hard drive means extra power usage.
3 USB hosts (in front hub)
You mean the internal ones or the externally-accessible ones?
2 SD card or MMC slots (2 slots) [both? one and the other?]
I'd say both SD.
1 lower battery slot PP3 or 6 AA cell slot
DC input help pick: https://en.wikipedia.org/wiki/List_of_DC_connectors
Don't know, don't really care.
Number of keys: 84 or 80-76? 71, 67?
84 I guess?
Pointing Stick mouse?
Yeah, that would def be nice.