- Install the USB driver on your laptop (see "Install driver")
- Download the IDE (see "Integrated development environment")
Need wifi to download the driver and IDE? We've got you covered. At least in the hangar, that is. You can use the SoftwareCircus2017 hotspot, with password cloudbusting.
Create an account for the IFTTT.com service. You'll need a (free) account in order to create applets. Applets are defined by an incoming and an outgoing service. We'll be using Webhook as the incoming service, and a service you'll select as the outgoing service. That could be sending a GMail, sending a tweet via Twitter, switching on a LIFX light, etc. After you've created an applet, click on the Webhook icon and click on the settings icon to look up the API key. The name you've given your applet, plus the API key, are all that is needed to get the pirtoifttt.lua script running.
If want to learn more about the Internet of Things you could decide to buy my book. Greatly appreciated.
The files in this repository are part of the workshop Build your own Internet of Things appliance, on Software Circus 2017 Cloudbusting. Attendees of the workshop create their own real-life IoT appliance using a microcontroller called NodeMCU and some clever software that connects to the internet.
In order to program the NodeMCU, a computer with USB is required (modern laptops with USB-C require a USB 2.0/3.0 hub, for instance the MacBook Pro). Drivers and an IDE need to be installed before programming can take off. Attendees are encouraged to install the appropriate driver and download the IDE (and if nessecary, Java) beforehand, to prevent wifi bandwidth degradation during the workshop.
In order to communicate with a NodeMCU via USB, a driver is needed. Drivers here are for Windows (CP210x_Windows_Drivers.zip) and OS X (SiLabsUSBDriverDisk.dmg). Install on your favorite platform and you're good to go. Word is, you don't need a driver with Linux, as it's part of the distro. If you want to share your milage, please contact me and I'll put your notes here.
A complete IDE is available, in the form of ESPlorer.jar, a Java program. Java needs to be already installed on your computer though. If nothing happens when you doubleclick ESPlorer.jar, you need to install Java as well.
In order to give you a running start, I've written a small introductory leaflet for Lua, called LUA-INTRO.md.
During the workshop, four projects were undertaken by the attendees:
- Make your led flash
- Connect to the internet
- A sensor that fires
- Measuring resistance
The first project, Make your led flash, did involve mounting the NodeMCU onto a breadboard, but no further wires or parts. Most attendees got their NodeMCU's on the breadboard just fine, using the schematic above as a guide. Mounting it involves a considerable two-thumbs push, after which the breadboard gives a satisfying 'clack'. Software from blink.lua below was uploaded onto the NodeMCU, which resulted in a flashing led. Attendees were challenged to change the delay parameter in order to make the led flash slower and faster. Also, led d0 was discussed and ways to have leds d0 and d4 flash interchangably.
The second project, Connect to the internet, was just about uploading the wifi.lua script. The wifi parameters were already set straight in the script and will need alteration for you own wifi hotspot situation. The script called a webhook every 30 seconds, with which the MAC address of the NodeMCU was sent, over the internet, through the IFTTT service, to a Google Spreadsheet that was shown a the big screen. Also, with each call to the webhook, an iPhone beeped. With 30 NodeMCU's calling home each 30 seconds, for a brief time there was a lot of beeping and buzzing.
The third project, A sensor that fires, involved a passive infrared sensor that was connected to the NodeMCU with three wires. One wire connected the PIR sensor to the USB power line of the NodeMCU, another connected the grounds of PIR sensor and NodeMCU. Finally, the output of the PIR sensor was connected to the pin marked d2 on the NodeMCU. At the event, we found out that some NodeMCU had faulty silkscreen, in that there were two datalines marked d2: d0, d2, d2, d3, etc. THe first d2 was actually d1, so that the PIR sensor had to be connected to the second d2. After downlading pirtoifttt.lua and creating an applet at IFTTT with Webhook as incoming service, this part of the code had to be changed:
-- Change this
APPLET = "put the name of the IFTTT applet here"
THE_API_KEY = "put the API key from IFTTT here"
(to be filled in)
blink.lua
Flashes the D0 led on the NodeMCU with a 1 Hz frequency.wifi.lua
Sets the wifi credentials and tests the connectivity by calling a webhook.testpir.lua
Prints a message onscreen if a PIR sensor fires.pirtoifttt.lua
Calls a webhook on IFTTT.com once a connected PIR sensor fires. Name of the IFTTT applet and the corresponding API KEY need to be filled in.testanalog.lua
Print the current value of the analog port on screen.resistancetothingspeak.lua
Calls a webhook on ThingSpeak.com with the current value of the analog port. The API KEY of the ThingSpeak channels needs to be filled in.
If you want to auto execute a lua script, you can put a dofile("yourscript.lua") inside a script that you name init.lua. Everytime you reboot the NodeMCU, init.lua is executed, which in turn runs your script. Be very careful with this feature though, as that auto execute happens in microseconds. If your script contains a bug that reboots the NodeMCU, you end up with an endless loop of rebooting.
It happens that a NodeMCU becomes unresponsive, usually as a result of calling a buggy lua script from an init.lua. You can use the python script esptool.py to reflash your NodeMCU, effectively resetting to 'factory' defaults. Examine the flashamica.sh shellscript in this repository to see how and what files you need (they're all here as well).