Look, Ma, No Computer! Microcontrollers on the Internet - Making Things Talk - page 128

Figure 4-8
The networked air-quality meter.

Microcontroller sets
meter voltage using PWM

Micro-
controller Meter

Microcontroller controls
Ethernet shield via SPI

Microcontroller sends
HTTP GET request
through Ethernet shield

Ethernet
shield

Ethernet shield connects to
router via Ethernet

Internet

PHP script responds
to microcontroller with
summary of AIRNow page

PHP script AIRNow

web page