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2021

  • in python
  • 3 min read

The Right Tool for the Right Job

With silversaucer.com now up and running with about half the functionality, I’ve turned my attention to try and displaying a bitmap on the Adafruit matrices.

I have two 32x64 matrices and have soldered my Adafruit Matrix Portal so it can display a 64x64 image. The first thing I learned was that the bitmap’s size correlates directly to the matrix. Thanks to Dan in Adafruit’s Discord server, I discovered the ImageMagick library can handle turning any image into a bitmap with a couple command line arguments. I ran through some random albums, downloaded the artwork and converted about half a dozen of them to bitmaps. They’re so cute and tiny!

64X64 bitmap of the album Beautiful Garbage by Garbage

And it looks like this:

Beautiful Garbage on the 64 x 64 Matrix

I’ve spent most of the week trying to do this. I can display a 64x64 bitmap from the filesystem, I can do a slideshow and display multiple bitmaps, but the one thing I can’t do: download and display over the internet. I’m not even able to download it, save it to disk, and then display it. One of the challenges of working with CircuitPython is staying within the memory limits as it’s a microcontroller, not a full blown computer like a Raspberry Pi is.

I’m trying to do the following:

  1. Parse the Discogs JSON to get the URL to the album’s cover art. (You must be authenticated to get a link to artwork).
  2. Take the image and convert it to a bitmap. ImageMagick can do this, so I need to save the jpg to the filesystem and then convert it and save it again (or display it in memory).
  3. Send a link to the image or bitmap to my local network to the device powering the LED Matrix.
  4. Display the bitmap on the LED Matrix

Even with almost 40k free, I run out of memory trying to download and display an 8k bitmap. I’ve tried to stream it without any luck. None of the CircuitPython libraries (image load seem to work no matter how I call it over the network. A few folks helped me out in Discord with some pointers, especially around showing how much memory is available which was super helpful, but no luck.

If there is one lesson I have learned since trying to port the sound reactive code for my speaker stand in trying to go analog instead of digital, is use the right tool for the right job. I spent dozens of hours tearing apart CircuityPython code and was never able to make it work. After spending a few days on this, I’m not going to make that mistake again.

If CircuitPython can’t display the image easily, let’s try a Raspberry Pi. I still have a bunch of them just lying around and the Matrix Bonnet is only $15, so I put in an order to Digikey yesterday. (Both of us being in Minnesota, their products get to me quickly).

Now I have a couple more design decisions to make. What kind of MQTT message do I want to send to my Pi locally? The image link? Convert the image to a bitmap and save on my DigitalOcean droplet or on my local Pi?

Longer term I’m leaning towards storing all this data in a database. The Discogs API seems a touch slow when returning a random album, and this would speed it up considerably, especially when loading and displaying an image. More updates next week after the Pi bonnet comes.

  • in python
  • 2 min read

December 2021 update and next steps

Now that I’ve semi deployed Silver Saucer, with working SSL, it’s time to think about what’s next as the year comes to an end.

I can either start working on the “Choose an album” functionality or I can start working on the IOT / image piece.

The “Choose” uses similar methods to the random functionality, but first it must return a bunch of lists and then display them in a drop down box. The user chooses what they want to play, hits submit, and that artwork appears. I need to build the methods to return the various lists and decide how many choices and what happens with each one on POST.

I don’t have Javascript installed, so one option is to take the HTMX course offered by Talk Python for interactive drop down menus.

Either way, some research and some work to do.

The second option I thought was going to be a lot easier than it turned out to be. I know the image URL location from the Discogs API, now I need to pass that to the MatrixPortal and 64x64 LED Matrix display and draw it.

I’ve spent most of the last two days trying to wrap my head around displayio and other drawing libraries. First, the LEDs only support bitmaps, and those have strict rules. ImageMagick has a convert tool built in to help with converting images at the command line. I can convert them, and display part of them, but I haven’t figured out how to display them at 64x64x yet, and that’s been most of the last two days.

But even before I know which image to draw, I need to send a message from the SilverSaucer.com server to the MatrixPortal. I’ve successfully installed MQTT using SSL (which also took a good chunk of all day Sunday) to do that. Now I just need to code the subscriber portion in the MatrixPortal and add the push in the web app. “Just”.

So that’s where I’m at. I need to pick one and stay with it as I’ve been kind of jumping around as I get stuck. And I’m very stuck, but writing things down does bring a greater clarity for what needs to be done.

  • in python
  • 3 min read

The Right Tool for the Right Job

With silversaucer.com now up and running with about half the functionality, I’ve turned my attention to try and displaying a bitmap on the Adafruit matrices.

I have two 32x64 matrices and have soldered my Adafruit Matrix Portal so it can display a 64x64 image. The first thing I learned was that the bitmap’s size correlates directly to the matrix. Thanks to Dan in Adafruit’s Discord server, I discovered the ImageMagick library can handle turning any image into a bitmap with a couple command line arguments. I ran through some random albums, downloaded the artwork and converted about half a dozen of them to bitmaps. They’re so cute and tiny!

I’ve spent most of the week trying to do this. I can display a 64x64 bitmap from the filesystem, I can do a slideshow and display multiple bitmaps, but the one thing I can’t do: download and display over the internet. I’m not even able to download it, save it to disk, and then display it. One of the challenges of working with CircuitPython is staying within the memory limits as it’s a microcontroller, not a full blown computer like a Raspberry Pi is.

I’m trying to do the following: 1. Parse the Discogs JSON to get the URL to the album’s cover art. (You must be authenticated to get a link to artwork). 2. Take the image and convert it to a bitmap. ImageMagick can do this, so I need to save the jpg to the filesystem and then convert it and save it again (or display it in memory). 3. Send a link to the image or bitmap to my local network to the device powering the LED Matrix. 4. Display the bitmap on the LED Matrix

Even with almost 40k free, I run out of memory trying to download and display an 8k bitmap. I’ve tried to stream it without any luck. None of the CircuitPython libraries (image load seem to work no matter how I call it over the network. A few folks helped me out in Discord with some pointers, especially around showing how much memory is available which was super helpful, but no luck.

If there is one lesson I have learned since trying to port the sound reactive code for my speaker stand in trying to go analog instead of digital, is use the right tool for the right job. I spent dozens of hours tearing apart CircuityPython code and was never able to make it work. After spending a few days on this, I’m not going to make that mistake again.

If CircuitPython can’t display the image easily, let’s try a Raspberry Pi. I still have a bunch of them just lying around and the Matrix Bonnet is only $15, so I put in an order to Digikey yesterday. (Both of us being in Minnesota, their products get to me quickly).

Now I have a couple more design decisions to make. What kind of MQTT message do I want to send to my Pi locally? The image link? Convert the image to a bitmap and save on my DigitalOcean droplet or on my local Pi?

Longer term I’m leaning towards storing all this data in a database. The Discogs API seems a touch slow when returning a random album, and this would speed it up considerably, especially when loading and displaying an image. More updates next week after the Pi bonnet comes.

blog/silversaucer

  • in python
  • 2 min read

The python3-discogs Library

In June 2020 Discogs announced they were going to discontinue support for the Python library they maintained. Shortly after, a few members of the community picked up where Discogs left off and announced a community version of the library.

I remember Discogs’ announcement but I forgot about the community. I had starred their repository at some point but randomly came across it again late last week.

I started to refactor my project on Friday to use the API to see if it would be easier than using requests to parse all the JSON. And it was. In one method I think I went from about 40 lines of code to 5. Yay APIs!

I didn’t understand the API thoroughly and got stuck on a few parts. The documentation is pretty good and has examples using the Python REPL but I still had a couple problems trying to put it together.

It turns out that the community members are very responsive and helpful to questions. I quickly received some pointers and help on the right way to do things and by the end of the weekend I not only had re-written the code to get a random album, but it was trivial to use the same code to get a random EP or single. In fact, I bet my code is way more Pythonic now as I’m only using one method for both.

This is another example of the beauty of open source. One group discontinues support but another is able to pick it up and keep it going.

With all the help I received, I wrote up a lot of the functions to use the API that would appear in a Python program and started a discussion and submitted a pull requestto update the documentation. The community has been welcoming and it’s the least I can do to give back.

  • in python
  • 2 min read

Silver Saucer Discogs Integration

The progress continues in moving Silver Saucer to FastAPI. I've spent almost all of my free time learning FastAPI from the Talk Python course. It would probably have gone faster if I was directly following the training course, but of course I'm doing my own thing.

I'm trying to do two things at the same time. First, build this in FastAPI, but use my own content, including CSS, page structure, and integrating the Discogs API instead of using a database. Second, I'm re-using some code (mostly the services that call the Discogs API) from the old Silver Saucer Pyramid site. I haven't touched that code in almost a year (for shame!) so I have to review that as I go.

Yesterday was a good day as I was able to wire up the Discogs integration using 90% of that old services code. It turns out when I create the class to manage the call, it's pretty specific as the first time I got it to work, I thought I was pulling in the record title, but instead it was the image URL, which I quickly converted to an image since I had something working:

Discogs returning an album image of Liz Phair's Exile in Guyville

From there, I was quickly able to call the rest of the data I wanted from the API and display it on the page. My memory of how the release date works must be off or requires more research. I thought I could pull both the release date of the specific album. For example, if it's re-issued like Garbage's BeautifulGarbage was last month, it would show a November 2021 date. But there was a main release date that should show 2001, but I can't seem to find it in the API. Oh well.

I was also able to update the HTML for the Genres and display that better than I did on the last site, parsing the list and showing it as sub-bullets. Another obligatory screenshot of everything working when clicking a random album:

Discogs returning an album image of Japandroids last album

I need to start coding the 7" / EP random function and then start on manually choosing a record. I have a couple questions on the training and thankfully Talk Python offers office hours, which are today!

Lots to do and I'm having fun doing it.

  • in python
  • 3 min read

SilverSaucer and FastAPI Progress Update

I’ve made significant progress this weekend in taking the Building Full Web Apps with Fast API training from Talk Python.

I’m enjoying the course and it’s cool to learn how async works in a web application. My site will be far less complex than the training and I’ll probably skip the database part, though I might want to wire that up later depending on how fast the Discogs API really is.

One of my favorite things about taking courses from Michael Kennedy and Talk Python is that the design patterns are consistent across courses. While my knowledge of Python is sill limited, I was able to pick this up quickly as I move from a pattern of controllers in Pyramid to doing most of the same work, just now in the viewmodel itself in FlasAPI. At one point I was pretty confused, because I had the knowledge of where we were going in the training, it just wasn’t there yet. As I stuck with it, it made more and more sense. (Nice work, Mr. Kennedy!)

Obligatory work in progress screenshot, with a new logo coming soon:

Silver Saucer homepage running on FastAPI

After I finish up coding the login piece, I’m going to start work on the Discogs integration. Hopefully it won’t be too hard to move that over as I did have it working in Pyramid. I spent way too much time yesterday working on Bootstrap and CSS to tweak the site. It was a bit frustrating as I really don’t know Bootstrap (or CSS for that matter). In the end it’s close to what I want, but I never was able to get horizontal lines working. I would never make it as a frontend developer.

I also had an aha moment for phase 2. In phase 2, when I select a record to play (or from random), I want it to display the album art on my LED matrix. I wasn’t sure how that was going to work if I did it on a public website. I was playing around with the idea of hosting it in the house on a Raspberry Pi for local access only, but doing the login chapter gave me an idea.

I’m going to disable the ability to register logins on the site and not link to the login page. I’ll be the only one who can login, and with the stored cookie, it will know it’s me. If it’s me, the site will send a MQTT message back to the MatrixPortal controlling the LED to display the art. I just finished setting up my MQTT Mosquitto broker, so hopefully I can get this to work. MQTT is new to me, but I know CircuitPython already integrates with it. But that’s why that is phase two. Let’s not put the cart before the house because I already have so many projects….

Adafruit Macropad Awesome List

Inspired by the CircuitPython Awesome List, I've created an Awesome List for the Adafruit Macropad.

I finally found some time to set mine up after I received mine this past summer in the Adafruit AdaBox subscription. I've 3D printed a couple of cases for it already and also programmed mine to work with the Onshape CAD software.

It's pretty cool and I was curious to see what others had programmed for macros for their applications and I figured why not create a list for everyone!

If you have any suggestions for what to add, please let me know or feel free to fork and send a pull request. Contributing guidelines are in the list and if you have any questions, you can find me on Twitter or on the Adafruit Discord (link in the list).

December 2021 Project Updates

Since my last blog post just over a month ago, I've been extremely productive. I have a few blog posts planned over the next week (no, really, I swear) sharing some updates on a number of projects I've been working on.

The 3D Printer I bought back in September has been keeping me very busy. Not just learning how to use it, but also constant tweaking and maintenance it needs. I bought a Creality Ender 3 v2 and as I like to joke about it, I have more time than money to spend on a 3D Printer. The Ender series is inexpensive, but it does take a lot of work to maintain it. I read once that you will learn as much about the hardware as you will about 3D printing if you buy an Ender series, and it's definitely true.

Learning CAD software has also been a time consuming process. Sure, there are thousands of pre-made plans you can print on your printer, but sometimes you need to customize something or build something just for you. In my case it's a new speaker stand for my AudioEngine P4s that integrates an Adafruit rp2040 Feather with Neopixel FeatherWing. Trying to figure out how to get the USB-C cable to work inside the stand was more complex than I thought it would be. As we speak, I'm printing - what I hope - is the final version.

The rp2040 Feather and NeoPixel FeatherWing is another project that I've spend considerable time on the last few months and more on that soon.

I also wrapped up version one of the Pi-Dial project last weekend. I made some tweaks to the code and it's working exactly as I want. If and when I get more time, I'm already thinking about version 2 which use Python's asyncio library. I could also pick up a Raspberry Pi Zero and make a version that uses that in a much smaller enclsoure. It may even be possible to embed that in a speaker stand as well, but the LCD would take up most of the front and I'd have to mount the rotary encoders on the side. I have enough projects though right now...

Last but not least, I've started working on Silver Saucer again. Looking at the blog, it's almost exactly a year since I spent significant time on it, which amused me. I just finished merging the change from Pyramid to FastAPI in and now I need to re-write the Discogs integration. I'll write more on that this week as well. I also have some cool things planned that will use an Adafruit MatrixPortal and LED matrices to display album art of what I'm listening to, but that's phase two.

More to come. Really!

Introducing pi-dial - Part 7 - Fixing the LCD

(Catch up on the pi-dial series of blog posts.)

In my last post, I teased about 3D printing the enclosure. That will come in the next blog post, I promise.

First, I wanted to talk about an issue I ran into with how text was displayed on the 16x2 LCD screen. Using the RPi_GPIO_i2c_LCD library when I changed the input, if the input had less characters than the new input, the extra characters were staying on the screen.

For example, if I started on the Xbox One input, I would see:

Input: XBoxOne

If I changed to the Vinyl input, I would see:

Input: Vinylne

Since XboxOne had 7 characters and Vinyl only had 5, the extra 2 characters were staying on the screen. If I used the clear() method, it caused the line to blink. When I stopped to think about it, it makes sense, as the method clears the space and redraws it. Since I’m constantly polling the receiver via the API to check the volume and input, it would redraw the screen based on the sleep call I make in the while loop at the end of the pidial-lcd.py file.

I really don’t want it to blink. It’s distracting when sitting on my desk.

A quick search later I came across the RPLCD library. They also have their docs on ReadtheDocs and after quickly scanning that, I used it as a replacement. I had to change just a few lines of code and voila! It’s clear command doesn’t blink and it actually clears the LCD before writing to it again and the extra characters were gone.

I’ve said it before and I’ll say it again: I love open source.

And make sure you thank an open source maintainer today.

Next up: 3D printing and assembly

pi-dial - Part 6 - When is a list not a list?

(Catch up on the pi-dial series of blog posts.)

In addition to controlling the volume of my receiver’s Zone 2, I want to be able to use a second rotary encoder to change the input. For example, I may want to change it from the Phono input that I use to listen to records to the Tuner input to listen to the radio.

The Denon AVR-3806 that I own has twelve total inputs, of which I’ve customized a few of the names. If I print out the list using the denonavr library, I see:

All inputs: ['8K', 'AUX', 'AppleTV', 'Bluetooth', 'HEOS Music', 'Phono', 'Retropie', 'SOURCE', 'TV Audio', 'Tuner', 'UBP-X700', 'Vinyl', 'Xbox One']

I’m using Python, so iterating through the list and / or slicing it to get to a specific position in the list shouldn’t be hard. Shouldn’t being the key word.

Spoiler: It was anything but.

If I attempted to iterate through the list, whenever the list position was equal to 8K, Bluetooth, or Source, the list would stop. It didn’t matter if I tried to move up or down the list. Now shame on me for not blogging about this earlier as it’s been almost two months since I worked on this particular piece, because I think there was another position in the list that did something similar. But of course I don’t have great notes or even a lot of commits to go back and look through.

I’m still very much a novice at coding, so I did what most newbies do. I wrote multiple if / else statements to try and figure out how to get around this limitation. I was 100% sure it was my code. Nothing I did worked, even as I wrote very procedural code to step through the list. I was on vacation the week I worked on this and spent literally the entire week trying to get this to work.

I finally broke down and asked my wife for help. In about five minutes she ripped up my if / else statements and wrote a methodthat passed a variable on whether the rotary encoder was turning up or down. And then she ran into the problem where the list would get stuck on positions 0, 3, and 7 (8k, Bluetooth, and Source) as you can see in the code’s comments. A couple hours later she was able to work around it. This was a fun way to spend a Friday night together!

Neither of us have any idea why those inputs caused the issue, but she was able to write a method to work around it.

The good news is that it wasn’t necessarily my code, the bad news is that I still have so much to learn about the best way to write my code.

The better news? The code is done! I have one program that monitors the current input and volume and displays it on the LCD and I have another program that can change the inputs and the volume.

Next up: 3D printing the enclosure.