Published June 16, 2019 © MIT

WiFi Connected Weather Station

It gets weather from the web and shows it on gauges. Perfect if your aesthetic is mid-century modern IoT.

IntermediateShowcase (no instructions)20 hours1,597

Things used in this project

Hardware components

SparkFun Snappable Protoboard

Any perf-board will do. You'll need some hook-up wire too.

30 AWG Bus Wire

Or use whatever you like to solder up to the back side of a protoboard.

Juken X27.168 Stepper Motor

Any stepper motor would work, but this one has an internal stop so you don't have to add anything to the design to find the zero position.

Juken X40 879B

Like the X27, this has internal stops at each end of its range of motion, so finding zero is no big deal. If you don't want separate temp and hi-temp readings, you can just get a 2nd X27.

Texas Instruments Dual H-Bridge motor drivers L293D

KAMEISHI 8 Inch Wood Desk Clock

Any container will work to hold the project, but a clock is a good choice so you can use the hands as indicators on the temperature dial.

20ga Stainless Steel Disc x 8.25" Diameter

This is optional. You can just use the clock face, but I liked the way the steel looked.

Waterslide Decal Paper

To print the gauge face on the steel.

Particle Photon

Software apps and online services

WeatherBit API

Provides current weather conditions, forecast high, and dew point.

OpenWeatherMap API

Particle Build Web IDE

Story

My aesthetic is mid-century modern IoT. I think it’s funny to make an internet-connected weather station and then put it in a retro-looking container with analog gauges.

The build is described at http://powerfulmojo.com/weather

The Hardware

I started with a breadboard, but the design of the circuit isn't very complicated, so I could have gone straight to protoboard.

Each H-bridge has 4 power pins, 4 ground pins, 4 connections to the Photon, and 4 connections to the motor. I was able to squeeze everything onto a 24x18 perfboard.

A picture of the bottom would be more informative, but this one is prettier

The X40 motor is a bit tricky. It has front contacts. That means you have to make all of the connections on the same side of the motor that the gauge hands attach to. The pin layout fits into a 0.1" pitch board.

Not a fan of the front contacts on this motor

I looked into a steel face in the first place because it's much thinner than the wood face the clock came with. I thought I wouldn't have to fiddle with extending the spindles. It turned out I had to extend the spindles anyway, so I could have used either face.

I glued stand-offs to the back of the steel and attached the boards with tiny bolts.

The Software

There are really good libraries to handle most of this project.

Stepper by facchinm runs the stepper motors.
HttpClient by nmattisson calls the weather API.
ArduinoJson by bblanchon parses the data returned.

There are two firmwares at https://github.com/powerfulmojo/WeatherMojo.

You only need one firmware. Choose whichever one you like.

weathermojo.ino uses openweathermap.org to show the current temperature and highest temperature it has seen today. It computes the dew point because OpenWeatherMap doesn't give it to you.
forecastmojo.ino uses weatherbit.io to show the current temperature and the forecast high temperature. It doesn't need to compute dew point because weatherbit provides it.

The duck is impressed

Other Details

I live in a very hot, very dry place. If you're not out in the desert like me, you'd probably want different temperature and dew point scales. Most of the year, the dew point at my house hovers around freezing, so that's the middle of my scale. Your humidity may vary.

The station gets weather where I live by default. If you build your own, you'll need to:

Replace the city ID in the firmware code (look it up here)
Use your own openweathermap.org or weatherbit.io API Key
Set minimum and maximum temp. and dew point values to whatever makes sense in your neighborhood