Pull in sbot's Arduino docs

Author: RealOrangeOne

docs/assets/docs/arduino-schematic.pdf

@@ -0,0 +1,47 @@
+# Arduino
+
+This board allows you to control GPIO pins and analogue pins. More specifically, it's an [Arduino Uno](https://store.arduino.cc/arduino-uno-rev3>).
+
+![Arduino Uno](../assets/img/kit/arduino_headers.png)
+
+## Headers
+
+We have supplied 2 screw terminal headers for your Arduino, allowing you to easily and securely attach your sensors.
+
+## The reset button
+
+The small button next to the USB socket allows you to instantly reboot the Arduino in case it
+isn't working. This isn't a guaranteed fix, but may solve some problems.
+
+## GPIO Pins
+
+The Arduino allows you to connect your kit to your own electronics. It has fourteen digital I/O pins, and six analogue input pins. The analogue pins can read an analogue signal from 0 to 5V. The board also has a couple of ground pins, as well as some pins fixed at 3.3V and 5V output.
+
+![Pin Map](../assets/img/kit/arduino_pinout.png)
+
+## Ultrasound Sensors
+
+Ultrasound sensors are a useful way of measuring distance. Ultrasound sensors communicate with the kit using two wires. A signal is sent to the sensor on the trigger pin, and the length of a response pulse on the echo pin can be used to calculate the distance.
+
+!!! warning
+    Ultrasound should only be considered accurate up to around two metres, beyond which the signal can become distorted and produce erroneous results.
+
+The sensor has four pin connections: ground, 5V (sometimes labelled
+*vcc*), *trigger* and *echo*. Most ultrasound sensors will label which
+pin is which. The ground and 5V should be wired to the ground and 5V
+pins of the Arduino respectively. The trigger and echo pins should be
+attached to two different digital IO pins. Take note of these two pins,
+you'll need them to use the sensor.
+
+!!! tip
+    If the sensor always returns a distance of zero, it might mean the *trigger* and *echo* pins are connected the wrong way! Either change the pin numbers in the code, or swap the connections.
+
+## Designs
+
+The schematic diagrams for the Arduino is below, as
+well as the source code of the firmware on the Arduino. You do not need
+this information to use the board but it may be of interest to some
+people.
+
+- [Arduino Uno Schematic](../assets/docs/arduino-schematic.pdf)
+- [Firmware Source](https://github.com/sourcebots/arduino-fw)