Lightning Cloud Lamp

Explanation of project

This project runs on a Raspberry Pi Pico sharing a serial connection with an Arduino Uno. The bones of this project were taken from another project that uses 2 Arduino Unos, one running the lightning logic an IR remote and another running logic to receive the IR signal and send it along using I2C protocol. Having built this version first, I thought I might be able to improve on it and control this via MQTT and home assistant. I mostly left the physical structure and code from the Arduino Uno driving the led strip, but altered it slightly to read bytes from the pico on a Tx/Rx connection instead of another Uno via I2C connection.

The relevant project instructions for the original lightning cloud and such are here; this is a great project to get started with if the micropython, MQTT, Home Assistant, etc portions aren't necessary for you. Either way, it's a good idea to read through those instructions so you can get an idea of how you want to create the cloud and some of the background info that I may have overlooked while writing this post. You could make this into a ceiling feature, a hanging lamp, or any number of other configurations. I also stuck some noodle LEDs on this to make a sort of "lightning" that flashes as you can see in the gif of the cloud at the top of this article.

Materials list:

• Raspberry pi pico W - Amazon
• Noodle leds - Amazon
• Arduino Uno or equivalent - Amazon
• Raspberry pi pico screen - Pimonori
• Logic level converter (5 to 3.3) - Amazon
• MOSFET driver - Amazon
• GPIO expander for pico - Amazon
• WS2812B LED strip - Amazon

Additional supplies:

• 5v 10a power supply Jumper cables
• Electrical box to house wires and parts
• Material to make actual cloud and structure (mine is made using this bell jar display). Depends on how you want to make it but could include:
  • Polyester Fiber fill
  • Spray glue (holds the polyster fibers together)
  • Steel wire (provides foundation for cloud shape; I used a cage of this to hold the polyester and LED strip)
  • styrofoam (if you follow the linked tutorial's idea)
  • micro usb cable for pico power

Getting started and code explanation

You'll want to first plan out how you are going to construct the cloud. This will influence the rest of your materials like the number of LEDs you use, whether or not you want the sound module (this is in the original lightning cloud project on makeuseof.com), if you want to include the LED noodle for the lightning bolts, etc.

As with many of my project write ups, this is being written post-completion, so I unfortunately do not have pictures of the in-progress steps. You can see the final product in the gif above and some of the menu functionality here:

The rough wiring diagram looks like this:

To set up the pico for this project, there is a great guide that Pimonori has put together here that will take you from installing the firmware to installing the best IDE for micropython, Thonny. If you already know how to do all of this and just want the firmware, you can head over to the pimonori github repo or browse the releases of the firmware here. To use the pimonori display pack, you have to flash the pico With the right firmware (it will have all the relevant methods built in), which should be the pico W version of the firmware.

The pico should be put on the GPIO expander (listed in the materials for this project). This will allow you to have the display pack along with access to the GPIO pins. Some pins are used by the display pack and you will have to avoid those in order for it to function properly, but sticking to the pins I have used should keep you safe here. The basic idea is that the menu is used to select the mode of the lightning cloud. Once a new mode is selected via the menu, two things happen: the mode selection is sent in bytes over a serial connection to the Arduino UNO, and the selection is also sent via MQTT to an MQTT server on the state topic.

The pico code that sets up the menu, handles the MQTT pub/sub pieces, and sends the bytes over serial is located in this file. The B and Y buttons are used to move the highlighted selection up and down while the A and X buttons are used to select a mode.

Looking into the Arduino Uno code shows that is a pretty straightforward state machine. It processes the incoming bytes from the serial connection with the pico W and sets a mode. In the loop() function, the mode is set in the receiveEvent() call, and directly after that the mode is passed through a switch statement to call the correct function to control the LED strip.

One side note is that there is a simple function that controls the LED noodles if you're implementing that feature. I controlled two LED noodles with one dual output mosfet, but I would go back and control them separately so this function is where you can add more output pins for doing so.

Home Assistant Integration

This project was made so I could control it via my Home Assistant instance. To do that, I had to connect the pico W to my wifi, set up an MQTT server (I have a Mosquito instance running on Home Assistant), and create some automations and helpers to string it all together.

The first thing you'll want to do is create an input_select helper in Home Assistant (seen below) that will represent the lightning cloud lamp's state. You will want to make sure the members of this input select exactly match the options of the pico menu.

After this is created, you will want to create an automation that does two things:

1. Upon the changing of this helper's state, it sends a message to the cmd/lightning_cloud/mode topic for the lightning cloud lamp
2. When the state is changed directly from the pico menu, a message will be sent to the state/lightning_cloud/mode topic. Every time this happens, the helper should match its state to the payload received on this topic.

The automation I created to do this can be found here.

Summary

All in all, this is a really fun project to make and is a fun conversation piece when people come over. If I owned my own home, I would have made a larger, more permamanent fixture. It was a fun exercise to learn more about I2C (not used in this project but used in the original tutorial on makeuseof) and serial connections. Things I might do differently might be to clean up the box I used to hold the pico W menu as it was a little messy and not having two LED noodles controlled by a single MOSFET would be ideal for a little variability in that feature.

I would love to hear feedback on this write up and project, so if you have any questions or comments feel free to find me on any of my socials that are linked on this website!