Re: [Gumstix-users] home automation with gumstix?

[Dave H. <dhy...@gm...>]

Hi Ors,

> Does this mean that an Overo Earth + Tobi (I do need the ethernet
> connection) would be enough? I don't need an LCD-capable extension to have
> the LCD control signals, right? I assume they are available on the COM for
> me to use as GPIO. How do I access them? I mean, physically. Same applies to
> the RS232s. I can't see a connector for them on the COM or the Tobi. Will I
> need to figure out their pins on the 70 or 27 pin connector and build some
> kind of connection board myself?

The LCD On the Tobi board, the LCD signals all seem to go a chip that
does the HDMI interface.

There are a bunch of pins on the 0.1" connector. The 6 PWM pins look
like useful candidates. Other pins are available if you're not using
them.

You can also connect stuff via USB. For example:
Something like this has 8 I/O pins:
<http://www.sparkfun.com/commerce/product_info.php?products_id=7841>

There is a company called phidgets which makes a bunch of I/O boards
which connect via USB.
<http://www.phidgets.com/>

They apparently have source for the drivers, although I haven't tried
using these myself.

>> advantage to using the robostix is that there are 8 ADC channels, and
>> the GPIOs are 5v. That only helps if you're connecting to 5v stuff.
>> For home automation, lots of stuff is 24 VAC, so you may find yourself
>> needing custom interface circuitry anyways.
>>
>
> Now that I had a second look I see 6 A/D lines listed on the Overo page. How
> do I access them from Linux?
> You mentioned that the GPIO on the robostix uses 5v. How about the GPIO on
> the Overo? Will I be able to drive a relay board that uses 5v inputs with
> it?

I'm not sure how the 6 A/D lines are used. I think that they go to one
of the power management chips on the overo board. I also seem to
recall several posting about this in the archives.

The GPIO on the overo is 1.8v. You should be able to drive a relay by
using a trasistor or MOSFET. Search for stuff on the beagleboard. It
uses the same processor and has similar voltage issues.

-- 
Dave Hylands
Shuswap, BC, Canada
http://www.DaveHylands.com/