Low-power device recommendation

Take a look at the TS 7000 from Technologics. Looks like 2W power. The cpu might be a little more thab you need though.

Joe

The guys at Technologic have a cheap board.

I think for a project like this you might want to think slightly smaller. Do you really need all those capabilities?

T.

Why Linux? If low power is truly your goal, look at a low power micro Take a look at some of the lower power application at CoAutomation.com

hmm and whats going to happen at night ?

easy

hard

very hard

foget it

NO WAY

now your funny

so do it in microcontroller ! perl and python can take care of the data on the server

definitelly NOT Linux

Pozdrawiam.

Power may be an issue, but lots of available documentation for the Linksys WRT54G. Definitely cheap, $59.95. A Broadcom chip running a 200MHZ MIPS core, The WRT54G has 4MB memory and 16MB ram. The WRT54GS has 8MB flash and 32MB ram.

Seattle wireless has some good documentation

Openwrt

Paper at Sveasoft

The serial port is accessible - requires a soldering iron.

--mikeb

(In comp.os.linux.embedded, $60.00 is cheap, but in comp.arch.embedded, $1.00 to $0.10 is cheap.)

Geez man, TS 7200 is 160$... definitely more expensive than Linksys unit!

Batteries, mon! :)

Why? From what I can gather TS-7200 consumes about 1.7W tops - easily doable with solar power & batteries. I'm not too technical so 'fraid programming a microcontroller will be too complicated. Even if I managed it (read: ported weather station polling software to a microcontroller), consider this: it's going to be a standalone unit, and connected to servers only via Internet (Ethernet or serial PPP + GPRS modem). It will need to send off data periodically to the server. Can a microcontroller handle this?

Peter

TS-7200 seems like a good choice. Can anyone explain to a newbie what DIO is?

Maybe not. Guess I'll have to explore microcontroller arena, although it sounds way too complicated at the moment.

Peter

At what latitude are you ? That will determine the height of the sun in the winter and thus the number of hours of daylight and the atmospheric losses (airmass). What are the weather conditions in the winter ? If there is a lot of clouds in the winter months, the solar cell output will drop even further. Thus you may need backup power for weeks or even a month. Thus, the average power consumption needs to be extremely low.

If this is a stand alone device, what do you need the Ethernet for ? Such high speed devices consume a lot of power.

So this is not a stand alone device after all ?

Why not run the power over ethernet or take it from the RS-232 handshake lines (assuming your system runs on a few milliamps).

If those are the requirements, then the system could be powered off for 99 % of the time to save power. Thus, you need a system which can go into deep hibernation and wake up with an external interrupt, such as a CMOS clock once a second or you need an OS that boots in much less than 100 ms if you do a restart every second.

This depends on your environment requirement.

If plenty of power would be available, it would be quite simple to keep the component and cabinet indoor temperature 5-10 degrees above the ambient temperature (even when a warm wet wind rapidly increases the temperature). This will prevent condensation on the components and you can use a box with holes in the bottom to ventilate the box and get rid of humid air when the temperature drops. With sufficient power you can even keep the indoor temperature above 0 C (since some components are not specified for subzero temperatures).

You must either do something about your power supply or rethink the division of labour in the system, e.g. transmit the raw measurements directly from a system with extremely low power consumption and do any hard processing in a system with more resources.

Paul

For an Ethernet/Web uC, look at

OK, that will take care of Internet connectivity via Ethernet. What about PPP dialup? Any MCs capable of doing this?

Thanks! Peter

Never mind, I found the answer... TINIm400

about

interface

You will need to regulate the solar cell output. If you want the thing to work at night you will also need battery power. Look at a shunt regulator for the charging the battery and a DC/DC converter to go down from 12V to

Peter

station

SIMM

(serial

Be sure to put in a switchmode converter with MPPT to optimize the power from the panel. A shunt converter set at a fixed voltage will be very in-efficiant

/Klaus

The TS-7200 will have more capabilities and expandability. The Linksys will be more fun for hacking. Its really up to you. T.

If you don't know about switching voltage regulators, please stop thinking about building solar driven intelligent devices.

-Michael

Hey, we all gotta start somewhere! ;) Will have to learn this stuph about voltage regulators I guess... this is a learning experience for me.

Peter

thats exactly what microcontrolers are for !

Pozdrawiam.