Hardware Reference
In-Depth Information
CatCam Redux
If the phone has a web browser, you don't
need to know how to program it to make
a mobile application. In this project, you'll
make a variation on the cat cam from
Project 5. But this time, you'll use a micro-
controller that serves files from an SD
card and an IP-based camera that needs
no computer to connect to the Internet.
MATERIALS
» Arduino Ethernet or Arduino uno and Ethernet
shield
» SD card reader that can read MicroSD
» MicroSD card
» IP-based camera
» Temperature sensor
» Relay Control PCb
» Relay
» 2 1-kilohm resistors
» 1 10-kilohm resistor
» 1 diode
» 1 transistor
» 1 LED
» 1 2-pin Screw Terminal
» 1 3-pin Screw Terminal
» Cat
» Air conditioner
» Country estate (optional)
My neighbor, let's call her Luba, has a cat named
Gospodin Fuzzipantsovich. Luba has a country estate
with cherry trees. She likes to summer there, at least
on summer weekends, but she can't take Fuzzipantso-
vich with her. Because the country estate has huge
expenses (samovars and the like), Luba can't afford
an air conditioner with a thermostat for her city place.
So, I made her a web-based temperature monitor. It
works as follows.
Luba opens a browser on her phone or laptop and
logs into the thermostat's web interface. She sees
the current temperature in her city apartment and
the air conditioner's state, along with a camera view
of Fuzzipantsovich. If it's too hot, she sets the trigger
temperature lower. If it's too cool, she sets it higher.
The interface updates the thermostat, and shows her
the new trigger point.
Mobile
Client
Desktop
Client
GSM
Network
Ethernet
Internet
DSL or cable
Before you build this project, you should diagram the
devices and protocols involved, and break the action
into steps to understand what needs to happen.
Figure 10-3 shows the system, and Figure 10-4 details
the interaction.
WiFi Ethernet
Ethernet
Home
Router
Camera
There are several pieces of hardware involved and
protocols to communicate between them. Many of
them are familiar to you by now. The Ethernet control-
ler on the Ethernet shield (or Arduino Ethernet)
Analog 0-5V
SPI
Temperature
Sensor
Ethernet
Shield
Microcontroller
Digital 0-5V
Figure 10-3
The system diagram for the CatCam 2 and air
conditioner controller.
SD
Card
Relay
