Re: mechanicals for an open voting system

From: Tom McCarty <tom_at_tom-mccarty_dot_com>
Date: Sat Jun 24 2006 - 14:31:20 CDT

Karl Auerbach wrote:

> I've been working with the PC-Engines WRAP board (about $150 qty 1)
> for a while now. It might not be the right choice, but I have found
> that these small machines can pack a lot of useful capabilities in a
> low-power, very reliable package. (The configuration I use burns all
> of about 3 watts; I run a Linux kernel on it and have a reasonable
> number of applications. I do all my own coding for it in Python.
> It's main drawbacks are lack of USB and lack of a video controller -
> these could be remedied by using it's mini-PCI slots.)

My thought was to start with a high-end board, and then scale back if
it's not needed. After all, I'll only buy one to begin with, and trying
to optimize too early is sin #1 when prototyping. Reducing latency for
a crisp system feel is also nice when appearances matters. The EPIC SBC
form factor is well-defined and well-supported, so any system designed
around this form factor should be useful for 10-20 years, with cheaper
boards coming out every few years.

> It'll be quite something if you can create a design that can be UL
> approved, can run all day on batteries, can be tossed about by grumpy
> teamsters, is proof against undetected tampering, and can be easily
> programmed, etc.

UL approval is pretty easy for something like this so long as it's
powered from a UL or CE approved power supply. Since the computer
equipment is all under 15 volts, they don't care about it at all (not a
shock hazard), and the touch screen should be a COTS part that's also
UL/CE approved.

> I can't overstate the need to get the right kinds of approval labels
> (or use parts that let us inherit such labels) - the last thing a
> county wants is for the fire marshall to shut down a voting place
> because some electrical or fire safety label isn't present.

Strictly speaking, UL approval is not necessary in the US. It's a good
CYA in the court of law, which in this litigation-happy society, making
it a very important thing, but it's not required by any electrical or
fire regulations in the US. In Europe, though, CE approval is required,
otherwise your devices can be seized and impounded.

Regardless, I'll be designing for both UL and CE approval, but that's a
long ways off, and is a simple issue compared to the security
requirements for the project.

> We dealt a bit with that in the proposal to the University of
> California, but not in great depth.

Is there anywhere I can read more about this proposal? I just haven't
been able to find anything, anywhere, about voting system mechanicals,
except to look at grainy pictures of Diebold TSx machines.

> Wireless is, to my mind, a no-no. Although I have heard that some
> counties want to bulk load using wireless. Personally I think that
> the county concern could be answered more safely by designing a
> package that easily mates with a docking station - that way we could
> avoid having any external connectors of standard formats that
> unauthorized hands might want to play with.

Agreed, wireless is a bad idea. Like a judge, we want to avoid even the
appearance of impropriety, and the idea that someone could be hacking
into it at any time would be distracting.

> People are also used to those wire and led seals to prevent
> undetectable opening of the case. Plus they are cheap, and if there
> are competing oversight bodies, each can have its own seal without
> displacing the others.

Yep, the vendors of the tags that read "warranty void if seal broken"
know how to reliably make tamper-evident seals, with holograms on them
to stifle forgery.

> One of the reasons I like the small computers is that they draw so
> little power that they could run all day on a single UPS charge.
> Unfortunately we probably can't say the same about the screen and
> printer.

We should be able to keep the power draw to a minimum, probably under 50
watts. The SBC I liked is 3W, a typical 17" touchscreen is 25W-35W, and
a printer should be <5 watts on average. A UPS will also draw about a
few watts, depending on efficiency and size of battery.

> We have to figure that sometimes the voting place is going to be in an
> old garage or something that was wired in 1910, with all kinds of line
> noise and no protective ground that can be trusted, all going through
> an ancient fuse of limited capacity.

Most transformers really don't care about line noise, it's all getting
stepped down to 3.3, 5, or 12V anyway.

> Printers have always been a troublesome part of the design. I've
> heard suggestions of using the kind of thermal printers that are used
> by airlines for boarding passes.

Hmm, I still haven't gotten a chance to find & read the old thread on
printers, glad there's been some discussion of it.

Thanks for the thoughtful response!


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Received on Fri Jun 30 23:17:10 2006

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