Tag Archives: electronics

Build a minimal Weather Underground station

Today’s post is a How-To for a project I recently completed: a temperature-only Weather Underground Personal Weather Station made from an ESP8266, a MAX31820 temperature sensor, and a few miscellaneous parts. The whole project fits inside a 3D printed project box for mounting on an exterior wall that is sheltered from the weather.

The open source project files are in my MAX31820WeatherStation Github repository.

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Cost-Reducing the Lunar Clock: IoT really is here

I have to confess that sometimes I need a push to make the right design choice.

It’s been a long time – way too long – since I worked on my Lunar Clock project. In the meantime, Sparkfun has introduced new, inexpensive microcontrollers aimed at Internet-of-Things applications. I knew one of those new microcontrollers would be perfect for the Lunar Clock, but I dragged my feet.

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Dog Water Bowl Scale, part 1: initial design work

Now that my Dog Bed Weight Scale is sending data, I’m going to have a go at a water bowl scale. The idea is that, like the bed, the bowl will periodically send its weight to a cloud. This data should tell me when Pippa drinks, when we refill her bowl, and (maybe) how much she drinks.

The work-in-progress sources on Github, contain the beginnings of the Arduino 101 Sketch, Bill of Materials (Parts List), mechanical design/construction details, and a day-by-day project diary. Continue reading Dog Water Bowl Scale, part 1: initial design work

Dog Weight Scale Part 9: Soldering the V2 circuit together

In my previous post I described how to use long break-away headers, and started soldering the circuit together.  In this post I finish transferring the scale circuit from the breadboard to a protoboard, and do a quick test mount of the circuit on the plywood scale base.

A reminder: I found that the Load Cell Amplifier was (by design) so sensitive to changes in resistance that just touching the resistors on my solderless breadboard caused large changes in the Amplifier output.  So I wanted to solder all the parts down.

Continue reading Dog Weight Scale Part 9: Soldering the V2 circuit together

Dog Weight Scale Part 8: Electronics, version 2

It’s a good time to recap: This project is a scale that will sit underneath my dog Pippa’s bed, so that I can measure her weight automatically, at night while she sleeps.  The project-in-progress is Open Source, at my CurieBLEWeightMonitor Github repository.  I occasionally tweet about it (among other things) as @bneedhamia.

In my previous post I covered how to choose matching resistors for the Load Sensor to convert the Load Sensor into a Load Cell that can be wired into Sparkfun’s Load Cell Amplifier.  In this post, I nearly finish building the breadboarded circuit and start transferring it to a soldered protoboard.

Continue reading Dog Weight Scale Part 8: Electronics, version 2

Dog Weight Scale Part 7: Choosing Matching Resistors

In my previous post, I worked through the calculations of weight and center of gravity when using four Load Cell Amplifiers instead of one.  In this post, I build the circuit for the first of the four Load Sensor / Load Cell Amplifier combinations I’ll be using.

The Sparkfun Load Cell Amplifier is designed to connect a Load Cell to an Arduino.  A Load Cell contains a full (4 resistor) Wheatstone Bridge, but a Load Sensor contains only half of a Wheatstone bridge.  To connect a Load Sensor to a Load Cell Amplifier, I need to add two resistors: R3 and R4 in the following diagram.  The dotted box represents the Load Sensor. The triangle in the middle of the diagram represents the Load Cell Amplifier.  As the weight on the Load Sensor increases, R1 decreases, which causes the voltage V1 to increase, causing the digitized amplifier output to increase.

Continue reading Dog Weight Scale Part 7: Choosing Matching Resistors

Dog Weight Scale, part 2: the electronics

As I said in the previous post, I’m using 4 Sparkfun load sensors, a Load Sensor Combinator board, a Load Cell Amplifier board, and an Arduino 101 to build a scale I can put under our dog’s bed, to passively weigh her whenever she’s in bed.

In the previous post, I cut the base for the scale from a sheet of plywood.  In this post, I’m assembling the circuit.

Continue reading Dog Weight Scale, part 2: the electronics