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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
Raspberry Pi

A good Raspberry Pi 4 case

My excitement for the new Raspberry Pi 4 turned into disappointment upon learning it couldn’t handle sustained loads without some sort of extra cooling solution. After installing it in this case, I’m happy to say things are looking stable.

The case comes with a fan and three heat sinks
Results of the load test
Categories
Projects Raspberry Pi

The Rover has dual steering!

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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

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Arduino Coding Gadgets Projects Raspberry Pi

The latest obsession

Categories
Projects Raspberry Pi

Raspberry Pi, touch screen, and a bluetooth speaker

A really simple project that delivers!

Includes:

The only ‘gotcha’ I came across was when sending audio to the Bluetooth speaker, the emulator I was using (snes9x, the default) got super choppy. This was resolved by adding pisnes as an emulator to EmulationStation and using it instead.

 

Categories
Projects Raspberry Pi

Raspberry Pi Touchscreen LEGO Stand

I recently acquired a couple of the awesome 7″ Raspberry Pi touch screens. They’re great except for one thing – how the heck do you hold it up out of the box?

Some third party manufacturers are selling stands, but can dirt-cheap LEGOs accomplish the same thing? Of course. I cooked this up in a few minutes. Three points support the screen perfectly, and a piece is added behind the USB ports to minimize sliding (though that hasn’t been an issue at all).

A downside to this design is that two USB ports are blocked on this model, but you may not need them at all as in my case.

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Coding Projects Raspberry Pi Scripts Video

Raspberry Pi + Garage door opener: Part 2

In Part 1 of my ‘Raspberry Pi + Garage door’ series, I showed a super simple way to control a garage door with a script that could potentially be ran from the Internet.

This part expands on that and tackles the issue: ‘How do I know the state of my garage door if I’m not at home?’

Because the code operates no differently than someone pressing a single button on the remote control, you would normally have to look with your own eyes to see if you were closing, stopping, or opening the garage door. This can be an issue when your eyes are nowhere close to it.

I wanted to come up with a solution that didn’t involve running new equipment such as a switch to detect the door’s orientation. I decided to utilize what I already had in the garage: A camera. Namely, this one: Foscam FI8910W

The idea is to use the camera to grab an image, pipe that image into OpenCV to detect known objects, and then declare the door open or closed based off of those results.

I whipped up a couple of shapes in Photoshop to stick on the inside of my door:

shapes_web

 

videostream
Shapes taped to the inside of the garage door

I then cropped out the shapes from the above picture to make templates for OpenCV to match.

Templates for OpenCV

The basic algorithm is this:

  1. Get the latest image from the camera
  2. Look for our templates with OpenCV
  3. If all objects (templates) were detected, the door is closed – otherwise it’s open

1423729418.65
Shapes successfully detected

 

To help make step 3 more accurate, I added a horizontal threshold value which is defined in the configuration file. Basically, we’re using this to make sure we didn’t get a false positive – if the objects we detect are horizontally aligned, we can be pretty certain we have the right ones.

I was happy to find that the shapes worked well in low-light conditions. This may be due to the fact that my garage isn’t very deep so the IR range is sufficient, as well as the high contrast of black shapes on white paper.

Currently I have some experimental code in the project for detecting state changes. This will not only provide more information (e.g. the door is opening because we detect the pentagon has gone up x pixels), but is good for events (e.g. when the alarm system is on, let me know if the door has any state change).

I’ve tested running this on the Raspberry Pi and it works fine, though it can be a good bit slower than a full-blown machine. I have a Raspberry Pi 2 on order and it’ll be interesting to see the difference. Since this code doesn’t need anything specific to the Raspberry Pi, someone may prefer to run it on a faster box to get more info in the short time span it takes for a door to open or close.

I’ve created a video to demo the script in action!

GitHub: https://github.com/twstokes/door_detect