If your website goes down, you want to be the first to know. Make it obvious when there's a problem by hooking up a big alarm light to a Tessel, which will ping your website every few seconds to check for trouble.
This project can also be viewed on the Tessel Projects Page.
Step 1: Materials
Step 2: Hack the Light
Unscrew the switch from the lamp cord (if you don't have a light with a switch, cut one side of the light's power cord)
Step 3: Expose the Copper
Peel back the cut ends and use the wire strippers to expose the copper.
Step 4: Insert the Exposed Wires Into the Relay
Using a screwdriver to press down on the tabs, insert both exposed copper ends into the two sides of Relay 1 on the Relay Module.
When the relay is latched "on", the two ends of the wire will connect, completing the circuit.
Step 5: Plug Things In
- Plug the Relay Module into Port A on the Tessel
- Plug in power to the lights
- USB power the Tessel (plug it in to your computer to program)
Step 6: Program the Tessel
Now we're going to add the logic to make the Tessel go online and check on your website. Note that you don't have to be a programmer in order to make this work– I've already written the code! You just have to copy it.
Please poke around in the code, and feel free to comment with any questions!
If you haven't used a Tessel before, you should follow the instructions on this page first to install it.
Programming your alarm light:
- Clone this repo ("repo" = repository for code. This might be a helpful read: https://help.github.com/articles/fork-a-repo/)
- From within the repo, `npm install` to install dependencies
- Ensure your hardware is set up properly by running `tessel run relay-test.js`. If nothing happens, check your connections and refer to the Relay Guide
- In `index.js`, change the wifi settings and site to monitor to suit your needs
- To run temporarily with logs, `tessel run index.js`
- To program for long-term use, `tessel push index.js`
- You can now unplug Tessel from your computer and power externally according to the guide
Congratulations, your light should be working!
It can be a little anticlimactic, since when everything is working properly, nothing should happen...
Here are the light patterns you should expect to see:
- Continuously off: all is well
- Continuously on: website being monitored is down
- Two-second bursts (on or off): system error; monitoring isn't working (reset the Tessel)