Hardware Reference
In-Depth Information
Figure 5-7.
The pressure mat is ready
Now, you make the first and only set of connections. You can safely power the pressure mat from the Raspberry
Pi; after all, it's just a big switch. Also, the pressure mat has no polarity so it's quite simple to work with.
1.
First, connect any ground pin from the Raspberry Pi to your breadboard's ground rail on
the side. I have selected GPIO pin P1-25 but you are free to use any of the ground pins.
2.
Do the same for the 3.3-V rail by connecting GPIO pin P1-01 to your breadboard's positive
power rail.
3.
Take the two wires from the pressure mat and connect them to separate rows on the
breadboard.
4.
Take a jumper wire from the ground rail and connect it to one of the rows from the
pressure mat. Halfway there!
5.
Install the GPIO cable: place the hook-up wire directly in front of the other row from the
pressure mat. Connect this GPIO cable to P1-07 (GPIO-04) on the Raspberry Pi.
6.
Connect your 10K ohm resistor from the positive power rail so that it is in front of the GPIO
cable. If you get this last part wrong, your mat won't work because you're not pulling up
the GPIO pin voltage correctly.
Take a look at Figure
5-8
to see the finished breadboard.
