Spark Core / Photon / Electron Water Sensor

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Code

About

 This is an internet-connected water sensor that will alert you via SMS (or any other webhook via IFTTT) if water is sensed. 

I am currently using this near my sump-pump to alert me if the pump fails. It can be run from either AC or battery power.

Hardware

For hardware, I'm utilizing a Spark Core hooked up to a Grove Water Sensor.

Nowadays, there are even cheaper options from Particle (formerly Spark), such as the Photon or Electron. 

The Grove Water Sensor's three wires (power, ground and data) are soldered to the top of the device.

I've 3D printed a simple "seat" for the Core to sit on so the external pins don't short. The STL is included under case/.

The Core is taped to my sump pump's pipe, and the Water Sensor is taped just below ground-level in the sump pump water pit.

Firmware

The Spark Core firmware is available under firmware/.

The firmware publishes these two events to the Spark Cloud:

• online when the device first starts up
• alarm when water is sensed. The payload is either on or off.

The firmware also exposes a variable alarmStatus: 0 means no alarm, and 1 means the alarm is active.

Software

The previous version of this sensor used a NodeJS app to monitor for events from the Spark Core. This app would then use the Twilio API to send me a SMS when there was an alarm.

Particle now offers Webhooks, which does this job for you. You don't have to run a NodeJS app. Once it senses an event from your Spark Core / Photon / Electron, it will publish an event to any web URL you specify.

Instead of using Twilio for SMS, I am now using IFTTT to send me an email, SMS and a Pushbullet notification all at once -- for free!

The creation of the Particle Webhook is pretty simple. First, install the particle-cli NPM module:

npm install -g particle-cli

Then, make sure you're logged in:

particle login

Next, create an IFTTT account. Then, create a IFTTT Maker page. On there, look for your private key (under Your key is).

Then, create a file called ifttt.json into your directory. Replace [your maker key] in that file with your private key. It should look something like this:

{
    "eventName" : "water_alarm",
    "url" : "https://maker.ifttt.com/trigger/alert/with/key/[your maker key]",
    "requestType" : "POST",
    "query" : {
        "value1" : "Water Alarm",
        "value2" : "{{SPARK_EVENT_VALUE}}"
    },
    "mydevices" : true
}

Last, you need to tell Particle how to integrate with IFTTT. Do this:

particle webhook create ifttt.json

You should see a success message. You're all set!

Parts and Cost

Total cost is around $21.90:

• $19 for the Photon
• $2.90 for the Grove Water Sensor
• Cables to connect the Water Sensor to the Core