This is a project that was years in the making, I went through many iterations that failed one way or the other. However, the final project was only started about a few months ago. It's great to see this project realized at last! The trigger really works, it has the appropriate sound effects, it has two firing speeds, and a "virtual ammo" system that you replenish by physically removing and reinserting the cartridge. So, where did it all begin?

The initial step of the process was to design the 3D printable case, which I did in blender. I found someone who extracted a model of the Necrochasm from the game itself and went to work sculpting out the finer details, hollowing out the interior, and adding LED areas. I also took this time to log into Destiny, and use my in-game Necrochasm to record the proper sound effects.

I exported the resulting pieces from blender to fusion 360 where I added the hardware mounting features. My vision for this prop was to have one area where most of the electronics were stored. This trapezoidal area at the bottom-front of the prop looked like it had the most storage capacity.

The CG-35 is a CircuitPython emulation of the Hewlett Packard HP-35 Scientific Reverse-Polish Notation (RPN) calculator designed for the Adafruit ESP32-S3 Feather and 3.5-inch TFT FeatherWing capacitive touch display. The calculator consists of a 10-digit LED-like display backed-up with 20-digit internal calculation precision.

This emulation reproduces the HP-35 calculator's v2.0 firmware where the change sign (CHS) key is active only after digit entry has begun. And because of the udecimal and utrig classes, calculation accuracy of monadic, dyadic, and trigonometric functions was improved. As an added bonus not present on the original calculator, a status message will appear just below the primary display when a calculation error is encountered.

The calculator's graphical layout was designed to mimic the aspect ratio of the original calculator -- that's why the left and right sides of the display screen were left empty. However, to provide a more reliable touch screen experience, the keys are somewhat proportionally larger than the original.

This project was inspired by Jeff Epler's DIY Desktop Calculator with CircuitPython project and Jeff's work to create CircuitPython versions of udecimal and utrig. Thank you Jeff!

GitHub Repository: https://github.com/CedarGroveStudios/CG-35_Calculator

Primary Code Module

The primary code module cg_35_calculator.py, imported by code.py, instantiates the display, plots the calculator case and buttons, and implements all calculator operational processes. This module uses a state machine design with the following named states:

• IDLE -- Display results or wait for input
• C_ENTRY -- Coefficient entry (keys: 0-9, ., CHS, EEX)
• E_ENTRY -- Exponent entry (keys: 0-9, ., CHS)
• STACK -- Stack management (keys: ENTER, CLR, CLX, STO, RCL, R, x<>y, π)
• MONADIC -- Monadic calculator functions (keys: LOG, LN, e^x, √x, ARC, SIN, COS,TAN, 1/x)
• DYADIC -- Dyadic calculator functions (keys: x^y, -, +, *, ÷)
• ERROR -- Calculation error

The calculator's display precision and internal calculation precision are specified using the variables DISPLAY_PRECISION and INTERNAL_PRECISION. Although the internal precision exceeds that of the original HP-35 calculator, it is recommended to keep the existing default settings of 10 digits and 20 digits, respectively, to avoid rounding errors.

The variable DEBUG can be use to provide additional internal register status via the REPL. This boolean variable defaults to False (no additional register status).

 

Basic premise:      Add lights (speed / noise / air-purity indicators, or needless dotstar+neopixel love), use small board to receive tachometer input and drive 24V fan PWM signal from particle sensor, along with new inputs for noise level.   Plus show off Blockly based programming on Adafruit IO, and update as and when the new maths functions become available, but for now write a quick CircuitPython version that illustrates all the desired functionality (to port to Adafruit IO).

Semi-finished code: - Functionally capable but no reactive light use, rainbow:
[Reproduced from https://github.com/tyeth/Ikea_ItsyBitsyEsp32_Air_Purifier/ ]

Wippersnapper

For those not in the know, WipperSnapper is Adafruit's plug-and-play firmware, which runs on their IO (think IOT) platform, offering free* data history(feeds) with graphs, dashboards, and automatic actions/triggers (along with integrating with other platforms like IFTTT). There is a paid upgrade for longer history, unlimited devices, SMS alerts, etc.

I love it because it's super quick and easy to test a sensor works, and to just get some data recording quickly. 

Goto a web-page, flash over usb, add sensors via control panel (feeds + graphs are automatic), done.

Under the hood it's an arduino sketch, so adding additional sensors via github pull requests is surprisingly easy (I've added a few because it makes my future tasks easier).

For this project I'm testing the Sensirion SEN55, which senses Nitrous Oxides (NOx), Volatile Organic Compounds (VOCs), with temperature and relative humidty as a reference (uses SGP40/41 inside), and measures particle counts at <1.0 micron, <2.5, <4.0, and <10.0 micron. The other models of this sensor have less features (SEN54: no NOx, SEN50: no NOx/VOC/Relative Humidity+Temp - only Particulate Counts).

From the standard drivers(arduino/Pi) created by Sensirion we can retrieve the typical particle size, along with the raw particle counts (or in SI units ug/m3), the temperature and humidity, and then two indexes for NOx and VOC. 
The NOx index has a baseline of 1.0, and if you hide the sensor under an upside down saucepan and use a lighter under the saucepan before sealing it back up then you will see a rise in the NOx index and then a return to baseline (1).
The VOC index is instead based at 100. You can detect VOC events from many things, the human breath can even be a source. I tested mine with a jar of clear nail varnish, but anything which you can smell, or smells chemically, is probably going to affect the sensor.

Connectivity-wise, it uses I2C, or other methods (UART?) which are as yet unpublished. The connector requires a JST-GHR 1.25mm 6 Pin compatible cable. The development kits include such a cable, but are heavily marked up cost-wise, like an additional 150% (£50 for kit, £20 for bare sensor). I advise getting a bare version with an additional cable from elsewhere (coolcomponents have a cable under £2). There is also a Grove connector version from seeedstudio.

Overview

Welcome to the Adafruit guide on creating a stunning Badger Mountain themed art piece! In this guide, we'll show you how to bring your artistic vision to life using the powerful Feather RP2040 microcontroller, along with an array of components including audio jacks, buttons, and LED strips.

Circuit Diagram

This article is for Circuit Python developers that use PIP and CircuitPython-Stubs in a Windows environment. 

Stubs are helpers for code completion hints with IDE's such as PyCharm, VSCode, and others.

Unfortunately PIP & CircuitPython-Stubs do not automatically stay updated.  These are things you must manually update when a new version of Circuit Python is released or whenever your heart dictates you want to update it.  This is a problem because I never remember to keep them updated and recently found out my version of stubs was last updated in Circuit Python 7.3.3 (we're now at Circuit Python 9.0.1). 

This is assuming you already have PIP and CircuitPython stubs installed.

The manual way to update them is:

python -m pip install --upgrade pip

pip install circuitpython-stubs --upgrade

These are the types of things I do not want to be required to remember to update.  I consider these things minutia that should automatically stay updated.

Windows Task Scheduler can automate the process of keeping both PIP and circuitpython-stubs up to date every time you log into Windows.  First we need to create a batch script and put it in a directory/folder that will always be available to Windows. 

I chose to put it in the following folder:

\Downloads\CircuitPython-Stubs_Updater

You can name the script whatever you'd like.  You can edit a .bat file as easly as a .txt file, you don't need a special IDE to do it, Notepad works fine for it.

I named my batch file:

circuitpython-stubs.bat

It resides inside of the CircuitPython-Stubs_Updater folder and includes the following code in the .bat file.

Introduction

Astronomy is my primary hobby and taking photographs of night-sky objects is my particular interest.  A downside to this hobby is that it is very weather dependent.  If it’s cloudy nothing can be seen.  Weather reports are important to monitor but they just serve the general area.  The sky conditions at my specific location are better monitored with an AllSky Camera.

An AllSky Camera is simply a camera with a fisheye lens that’s pointed up into the sky.  A program takes pictures of the sky all night long so checking the sky conditions can be done by looking at the latest sky image.  Is it too cloudy to take images?  Are clouds starting to move in?  Just check the AllSky Camera!

The Issue with Dew

Unfortunately, the dome of the AllSky Camera is prone to have dew forming on it when the humidity gets high.  Once that happens, the Allsky images are totally unusable.  To combat dew, many AllSky Cameras have a dew heater built into them.  The heater in my camera is very simple:  Apply 12 VDC and the heater is on.  Remove the voltage and the heater is off.  This applies about 10 W of power to the heater, and it does get hot enough to keep dew from forming on the dome.  Sometimes it gets too hot.

If the humidity is moderate the 10 W of power is way more than needed to keep the dome clear.  An unwanted side effect of too much heat is that cameras don’t like it.  The hotter a camera gets the noisier, or grainer, its picture becomes.  This is especially apparent with long exposures and AllSky Cameras can take up to 60-second exposures under a dark sky!  The better solution is to vary the amount of power applied to the heater so that only enough is applied to keep dew from forming, and no more.

 

The goal of this project is to build a Python based handheld and battery powered scientific calculator the size of a cigarette box (well, pocket calculator). Scientific, as in "reasonable precision". Float32 (single precision) is certainly acceptable for a display precision of, say 6 or 7 digits, but the follow-up rounding errors are not - at least not for me. I experimented with Decimal math before but ended up having to fight memory constraints with jepler-udecimal (https://github.com/jepler/Jepler_CircuitPython_udecimal) and my own extensions even on a Feather RP2040 with 256kB of user RAM. So I eventually decided to make a custom CircuitPython build and try to enable float64 (double precision) math. (Thanks to the Adafruit folks for their help!). Needless to say that float64 is entirely handled in C without the help of a potential floating-point unit (FPU) but then this approach is still much more CPU and memory efficient than implementing everything in Python.

The code for this project is on https://github.com/h-milz/circuitpython-calculator/ and will be discussed in this article.

The terminal window displays a couple of features of this tiny machine, from top to bottom: calculating pi using arctan(1), the arsinh of a complex argument, multiplying two numbers with uncertainties, and multiplying two fractions including reducing it to lowest (positive) denominator.

The dongle on the lower right is a PCF8523 RTC hanging off the Keyboard Featherwing's STEMMA Qt connector (which, sadly, is unusable if you want a handheld with a back cover ... What did arturo182 think?)

On the backside you can see the Adafruit Feather M4 Express and the LiPo battery, which is fixed to the Featherwing using a double-sided adhesive foam strip.

Introduction

The flight simulator industry has spawned dozens of custom controllers for those who are looking for a more realistic and entertaining experience. These controllers range from yolks and throttles to communication and GPS systems and their price can rival the costs of actual aviation equipment.

Thankfully there is a way to create your own controllers using low cost microcontrollers, buttons, encoders and many other input devices. There are even ways to output settings to LEDs, LED segments and displays but this guide does not cover output scenarios.

For this hookup guide I am using a controller I made for myself. The G1000 glass cockpit has a dual-rotary encoder in the lower right corner labeled FMS (Flight Management System) that is a pain to control with a mouse, even more so while the plane is in the air. So I decided to build my own controller to simulate the G1000 corner. My controller includes the FMS encoder knobs and the 6 buttons that tend to be used at the same time.

You can find the source files and STL files I used on GitHub.

The Controller

For my FMS controller I found the PEC11D-4120F-H0015, a dual concentric rotary encoder (meaning it has an inner and outer encoder ring that can turn). This is not the FAA approved version on the actual G1000 but works the same and cheaper. The dual rotary encoder is similar to a single encoder except has two sets of A/B/C pins. The encoder also has a push switch. The push buttons above the encoder are standard push buttons.

The encoder and buttons are wired to a Feather board but almost any board that can run CircuitPython with USB HID enabled will work.

I just couldn't bring myself to use the standard practice of soldering pins onto breakout boards using a solderless breadboard in spite of the recommendations and endorsements of some famous solder artists. I would cringe thinking that the heat would eventually warp the plastic portion of the board. It is a solderless breadboard after all.

Fortunately, after placing many Adafruit orders over the years, I had build up quite a collection of free half-sized Perma-Proto breadboards. The solution for creating a non-destructive soldering jig became obvious. Stack four Perma-Proto PCBs together, use a couple of M3 nylon screws and nuts, and place some rubber feet on the bottom. Voilà!

Sadly, the Perma-Proto board is no longer offered as a free product promotion. That's okay; I still have enough in the inventory for many future projects. And coasters. I have coasters.

If you've been playing the awesome new co-op game Helldivers 2, you'll be familiar with the "stratagem" gameplay mechanic in which you summon various weaponry from airborne and satellite craft. This mechanic requires you to hold down a key/button to activate the stratagem input mode, while entering a sequence of directional key input.

Often during the game I tend to get overstimulated in the middle of a heated battle and my mind goes completely blank when trying to recall the one of the myriad codes I need to use to summon the effect I want. Even though the game UI displays them, it's still pretty hectic to precisely enter the sometimes lengthy codes when a giant scorpion is trying to rip my head off. To help spread liberty and democracy in the most efficient way possible, I thought I'd try to see if I could set up some stratagem macros using the awesome MACROPAD Hotkeys project from Phillip Burgess. NOTE: For simplicity, this particular setup mimics keyboard input, so until I hear otherwise I'm assuming this only works on the PC version of Helldivers II.

Custom Code

It took a few tries to figure out how to set up the macros so that the game would consistently accept them. Thankfully, the MACROPAD Hotkeys project is incredibly versatile and I was able to do this using the built-in features of the project without having to modify any of the core code. The main factors involved in getting this to work seemed to be:

1. After pressing the stratagem input button, a significant delay was needed before the game would accept the directional input. I'm assuming this is due to needing to wait for the UI to fully present in-game before allowing further input. With experimentation it seems like the smallest delay possible is about 0.4 seconds.
2. Each directional key needed to be pressed for a certain duration. The smallest duration I've tried for this so far is 0.05 seconds.
3. A small delay is needed after each direction key is released. The smallest duration I've tried for this so far is 0.05 seconds.

In the /macros folder on my macropad CIRCUITPY drive, I created a new file named helldivers-2.py. Since I anticipate changing this file frequently as I progress through the game, I wanted to make it as simple as I could to add/edit new macros, so that I could even edit them in real-time as I played the game. To make this a little easier, I wrote a bit of custom code at the top of the file.

The arbitrary waveform capability along with ADSR envelopes and filters has made it very easy to create custom musical voices with CircuitPython synthio. And if you use an additive synthesis tool like WaveBuilder, you'll begin to quickly amass quite a few custom musical voices as you experiment with the nearly infinite number of oscillator combinations.

Hearing Voices

Up to this point, I've been keeping track of the numeric specifications for WaveBuilder oscillators and synthio.Envelopes in project code or scribbled on a note pad. That means that when building a new project that needs to use a previously created voice, I'll cut and paste the voice definition code into the new project. The process works, but isn't ideal. What if a synthio musical voice could be loaded from a collection in a file folder, kind of like working with a font file?

So a concept for the WaveStore project began to develop. Here are the initial requirements.

• Library File Management -- We'll make it easy at first and just work with a collection stored on an SD card. No need to tax the brain to conjure up a way to write to the CircuitPython root directory just yet. After creating and storing a voice to a file, we'll manually copy the files from the SD card in order to use and share between projects.
• Files -- In the spirit of keeping it simple, only files representing waveforms and envelopes will be created. Those objects form the fundamental elements of a musical voice. Perhaps we can add filters and other effects later.
• Library File Names -- Waveforms will be stored in a standard wave file with a .wav extension,  thanks to the awesome Adafruit_CircuitPython_Wave library. Envelopes and filters definitions will be stored in plain text files with .adsr and .fltr extensions but will transform to synthio.Envelope and synthio.BiQuad objects when retrieved.
• Icons -- Imagine being able to select a musical voice waveform or envelope by touching a screen icon. Functions will be provided to save and retrieve bitmap images of waveforms and envelopes as well as capturing the contents of an entire screen. We'll start with 64x64 pixel bitmaps created by WaveViz. A graphical frequency response representation of a bi-quad filter's coefficients is in the works but is a bit beyond today's skillset. There's a potential workaround, but I'd rather derive it directly from the numbers. Hoping for an epiphany soon.

In the future, more features will likely be added to WaveStore such as support for filters and on-screen icon buttons -- as my experience and Python skill set grows. What would you add?

Enter WaveStore

WaveStore GitHub repository

WaveStore is under development but is available for testing. The current alpha version of the WaveStore class provides the following helpers:

• Wavetables
  • read_wavetable -- Read a .wav file and return a memory view object.
  • read_wavetable_ulab -- Read a .wav file and return a ulab.numpy array object. The ulab array can be mixed with other wavetable array files.
  • write_wavetable -- Format a wavetable and write it as a standard .wav file.
• Envelopes
  • read_envelope -- Read an .adsr file and return a synthio.Envelope object.
  • write_envelope -- Write a text interpretation of a synthio.Envelope object to an .adsr file.
• Bitmaps
  
  • read_bitmap -- Read a .bmp file and return the bitmap as a TileGrid object that can be added to a displayio.Group object.
  • write_bitmap -- Write a bitmap image to a .bmp file.
  • write_screen -- Write the screen contents to a .bmp file on the SD card.
• Utilities
  • get_catalog -- Returns a list of files in a specified folder.