Making Things Talk

126 MAKING THINGS TALK

In this project, you’ll make a networked air

quality meter. You’ll need an analog panel

meter, like the kind you find in speedom-

eters and audio VU meters. I got mine at

a yard sale, but you can often find them in

electronics surplus stores or junk shops.

The model recommended in the parts list

here is less picturesque than mine, but it

will do for a placeholder until you find one

you love.

MATERIALS

» 1 Lantronix embedded device server Available

from many vendors, including Symmetry

Electronics (www.semiconductorstore.com) as part

number CO-E1-11AA (Micro), or WM11A0002-01

(WiMicro), or XP1001001-03R (XPort).

» 1 solderless breadboard such as Digi-Key part

number 438-1045-ND, or Jameco part number

20601.

» 1 USB-to-serial circuit such as the FT232RL, or

RS-232-to-serial circuit such as the MAX3323, as

shown in Chapter 2. Use the second of these if you

don’t have a USB port and have to use an RS-232

serial port. Otherwise use the first.

» The micro-to-breadboard connector from the

previous project (or make another one if needed).

» Arduino module or other microcontroller.

» 1 voltmeter Get a nice-looking antique one if you

can. For a placeholder, you can use part number

48J6151 from Newark (www.newarkinone.com).

Ideally, you want a meter that reads a range from

0–5V, or 0–10V at most.

» 5 LEDs

An Embedded Network Client Application

By now, you should be pr ...