1. By: Bill Gesner

2. Goal
 Receive weather information from two RJ-11
connectors(phone jacks).
 Transmit the data wirelessly from the Texas
Instrument micro Mavrk to a Texas Instrument Mavrk.
 Send the data to a PC and a secondary embedded
device.

3. Weather Meter Design
 Rain Gauge: The rain meter pools water which causes a
circuit to close once per 0.011” of rain.
 Anemometer: The speed of the wind is recorded by
closing a circuit once per rotation.
 Wind Direction: The direction of the wind causes a
change in resistance across the output.

4. Input circuit design

5. Rain Gauge Input
 A digital input port was used to detect the current
state of the circuit.
 The number of times the circuit was closed was
counted.
 Once every two seconds the count was transmitted
wirelessly to the base station.
 The data was sent to the PC via USB as well as the
serial port.

6. Wind Speed Input
 Similar to the Rain gauge method.
 The Anemometer circuit closes once per revolution. A
wind speed of 2.4 km/h causes the switch to close once
per second.
 The amount of times the Anemometer circuit closed
was counted and transmitted once every five seconds.

7. Wind Vane Input
 The direction of the wind alters the resistance across
the wind vane output.
 An analog to digital converter input was used to detect
the voltage drop across the wind vane which was
connected in series to a 10kOhm resistor.
 The value of the ADC was transmitted wirelessly once
every two seconds.

8. Temperature
 A built in temperature sensor is included on the micro
Mavrk.
 The temperature sensor output is connected to the
ADC similar to the wind vane input
 Functionality of the temperature sensor is optional to
allow for the possibility of an extra ADC input.

9. Humidity
 A secondary chip can be attached to the micro Mavrk
to add humidity detection.
 The TMP-112 replaces the output of the built in
temperature sensor with the output of a humidity
sensor.
 The temperature data is then available via I2C with
more precision.

10. Light
 The brightness in the room can be read from the micro
Mavrk.
 This functionality can be enabled using the standard
micro Mavrk or the TMP-112.

11. Output
 The output of the data is then sent to the Texas
Instrument demonstration software “App Monitor”.
 This displays all built in functionality such as
temperature, humidity, and light levels.
 The raw data is also transmitted serially via UART.

12. UART output packet structure
 The data sent to secondary embedded hardware
required a data structure to ensure valid transmission.
 In total 7 bytes were transmitted
 2 byte header
 1 byte to identify what sensor was transmitting data
 2 bytes of data
 2 byte footer

13. Conclusions
 The mavrk system is a modular and versatile
development platform that can be used for swift
prototyping.
 The sparkfun weather station is straight forward and
well documented
 Code Composer is an easy to use and friendly
environment.