Hardware Reference
In-Depth Information
[ 522.400407] tsl2563 1-0039: model 5, rev. 0
[ 522.402650] i2c i2c-1: new_device: Instantiated device tsl2563 at 0x39
There is a new device node (
1-0039
) in
/sys/class/i2c-adapter/i2c-1/
. Inside that
node is a
iio:device0
mapping, and inside
that
mapping directory are several devices
that allow you to get readings:
$ ls -l /sys/class/i2c-adapter/i2c-1/1-0039/iio\:device0/
...
-rw-r--r-- 1 root root 4096 Sep 16 20:37 in_illuminance0_input
-rw-r--r-- 1 root root 4096 Sep 16 20:37 in_intensity_both_calibscale
-rw-r--r-- 1 root root 4096 Sep 16 20:37 in_intensity_both_raw
-rw-r--r-- 1 root root 4096 Sep 16 20:37 in_intensity_ir_calibscale
-rw-r--r-- 1 root root 4096 Sep 16 20:37 in_intensity_ir_raw
...
These files contain the current raw sensor values for the calibration scale and the
infrared and combined luminosity readings. To do anything with them, you'll have to
convert them using the math in the
TSL2561 datasheet
.
Listen to Aircraft Transponders
HACK 43
Every day, thousands and thousands of airplanes are flying the friendly
skies. Some might be flying over you right now! With a USB TV tuner and
a Raspberry Pi, you can listen to the aircraft transponders and find out
which planes are up there.
An aircraft transponder is the device on board a plane that responds to radio fre-
quencies and helps identify the plane for various systems, including radar. They gen-
erally send a few pieces of information, including altitutde, location, and what's called
a “squawk” code that further identifies the flights. If you want to listen to aircraft
transponders, it will help if you're within five miles of a local airport, but the occasional
commercial plane passing by will be sufficient—you'll just have more infrequent re-
sults.
Here's what you'll need:
• Raspbian
•
NooElec R820T
:
these devices are easily found on eBay as well, but be sure you
have the E4000 chipset variant. Look for “E4000” in the description to make sure
your purchase will work with this project or refer to the
list of supported hard-
ware
. This device is also called an RTL-SDR, or RealTek Software Defined Radio,
because of the vendor of the analog-to-digital chip it uses. It looks like a flash drive
(see
Figure 4-10
), but it is so much more.
