Categories
Arduino Projects

nRF24L01+ and SLIP

Currently a work in progress, I’ve nerd sniped myself to get TCP/IP working over SLIP with a pair of Arduinos equipped with nRF24L01+ radios.

Categories
Arduino Gadgets iOS Projects

iPad Zoom mute button

At work we’re primarily using Zoom for meetings while we’re in remote mode. Due to the recent problems found in their desktop software, I run it only on my iPad to provide a little more security (thanks to iPadOS’ sandboxed environment), plus the front facing camera on my iPad Pro is superior to my iMac and MacBook Pro’s.

The first issue I found with this setup was that I wanted to get the iPad into a position more perpendicular like a web cam, rather than the angled up shot below my face. I don’t think anyone wants to look up my nose unless I’m on a telehealth call, so I ordered this flexible stand for about $25 from Amazon and got it mounted:

Trying to bend this thing will give you a workout.

So far so good, until my first meeting. I wanted to follow conference call etiquette by muting myself when I wasn’t speaking, but it was a pain to reach and manually tap the mute button every time. Plus, although the flexible arm is super strong, it’s still going to wobble wildly if you touch the iPad and your video is going to show that.

Was there a way I could toggle muting myself without touching the iPad? After a quick Google search, the answer was YES!

The attached keyboard (Smart Keyboard Folio, Magic Keyboard) didn’t make any sense in this case, but a Bluetooth keyboard would be perfect!

Logical answer

The logical answer is to connect up a Bluetooth keyboard and hit Command + Shift + A when you want to toggle muting your mic, and you’re done. That’s it.

I’m not totally logical

Of course, the route I chose was different. I have enough keyboards on my desk, I really just want one button to do one thing.

Recently, I rigged a button to turn pages in the Books app over Bluetooth. We should be able to do the same thing here, right?

Figuring out the codes

The objective is clear: When we press a button, we send “command+shift+a” to the iPad.

Using Adafruit’s HID codes, we find:

  • Left shift == 0x02
  • a == 0x04

But what’s the “Command” button? Is that the “meta” or “GUI” key? If so, is it a modifier or just a regular key?

Lots o’ troubleshooting

I spent a lot of time troubleshooting over and over:

Compile a new sequence of commands, upload new firmware to the microcontroller, re-pair with the iPad, open Zoom and try to mute: No go.

From what I could tell, “shift + a” were working, but “shift + command + a” wasn’t. It wasn’t until I almost gave up that I had a breakthrough:

Let’s try remapping another key to “command” and see if we can press that key. How about Caps Lock?

It worked.

In my code I wrote:

// gold
ble.println("AT+BleKeyboardCode=02-00-39-00-00-00-00"); // shift + caps lock
ble.println("AT+BleKeyboardCode=02-00-04-00-00-00-00"); // shift + a
ble.println("AT+BleKeyboardCode=00-00");

This is as if the user pressed “shift + caps lock”, and then “shift + a” at the same time, then released. Now the Zoom app was getting the proper command from a Bluetooth “keyboard”.

Hardware

This setup is virtually identical to what I have here, it’s just a different button.

The USB cable coming in is only for power, and if I had the Adafruit Feather version on hand I would’ve used that with a battery so the box would be totally wireless.

The button is no more complicated than this tutorial.

GitHub: https://github.com/twstokes/labs/tree/master/zoommuter

Improvements

A better version of this would be:

  • A button to also toggle video
  • Using the Adafruit Feather BLE version with a battery so the box would be entirely wireless
Categories
Arduino Projects

Bluetooth LE Page Turner

Added to the labs, a proof of concept page turning button: https://github.com/twstokes/labs/tree/master/pageturn

Categories
Arduino Coding Golang Raspberry Pi

A Tree Divided

See the GitHub Repo!

The tree reacting to Clemson scoring

Idea

Every year Clemson plays USC for their state rivalry game. I pull for Clemson and my wife pulls for USC, so we’re what you call a “House Divided”. Since this game takes place on or after Thanksgiving, it’s a great time to incorporate the LED Christmas tree and troll my spouse!

The tree works like this:

  • When a team scores, it plays their fight song and lights up with their primary and secondary colors.
  • The lights on the tree are distributed by the ratio of points. When it’s tied, they each get 50% of the lights. If Team A has 2/3 more points, they get 2/3 more lights in their color.
  • The ring under the star at the top of the tree is the color of winning team. If they’re tied, it’s split.
  • When the game is finished, the tree is the color of the team that won.

Software

I used Golang for the software since I primarily write code in another language and want to get better at it. It makes use of various interfaces to aid in testing and abstration:

  • The Fetcher interface gets the latest game state from a data source
  • The Player interface plays audio at the given path
  • The Illuminator interface controls a light source (in this case the LED tree)

The source code for a local data fetcher is included in this repo only. The remote fetcher I built may or may not have used an API meant for this sort of consumption. It simply fetched from a remote data source, unmarshalled a JSON data structure, and supplied what the Fetcher interface needed.

The code runs on a Raspberry Pi and communicates with the MCU via serial. An iHome IBT63 speaker is used to play audio from the Raspberry Pi. I didn’t use the Bluetooth connection and instead used the shared power and audio connector, plugging one end into the RPi’s stereo jack and the other into the USB port.

I cross-compiled from my Mac using the rpi.sh script in the executable’s directory.

Firmware

  • Uploaded using PlatformIO
  • Runs on a NodeMCU ESP8266
Categories
Arduino Projects Raspberry Pi Swift

Controlling the Rover’s camera with an iPad gyroscope

The Rover got its own iOS app and I implemented a neat way to control the camera servos.

Categories
Arduino Projects Raspberry Pi

A new way to control the rover!

Categories
Arduino Projects Raspberry Pi

Rover progress

Categories
Arduino Coding Gadgets Projects Raspberry Pi

The latest obsession

Categories
Arduino Projects Video

NeoPixel LED Christmas Tree

https://twitter.com/tannerstokes/status/945026163805769728

See the GitHub repo for a parts list, wiring diagram, and Arduino code.

Categories
Arduino Projects Swift

The start of a project: SafeEject

The time has come: My 2009 Mac Pro has been retired and replaced with a 2016 MacBook Pro. Not only has the temperature in my home office dropped about 4°F, but I can now run the latest macOS, Xcode, and Docker, which I need for work (for that money stuff). I held on to the Mac Pro as long as I could, though, and I can confidently say that the “cheese grater” desktop is the best machine I’ve ever purchased.

A new setup presents new challenges. One issue I’ve found is switching states between “docked” and “undocked”. I put this in quotes since Apple doesn’t have a true docking station solution. Because of this it’s way too easy to rip out the USB connectors when “undocking”, which could lead to a dirty removal of a volume (e.g. something hasn’t been flushed out of cache to the actual hardware yet and data is corrupted / lost). Since I have a Time Machine drive connected at my desk, this can happen if I don’t remember to eject it from Finder.

I think this process would be easier with an external button to do the work for me before disconnecting the laptop. Currently in the hack phase, I’ve wired up an Arduino with an RGB pushbutton that communicates to a macOS app. When it’s time to undock I simply press the button to unmount all volumes and get visual feedback that it’s safe to pull the plugs…

 

https://github.com/twstokes/safe-eject