Smart Poi

Emulating Poi Spinning patterns in software

Several years ago I read an amazing scientific paper on the mathematics of Poi patterns, by DrexFactor – you can have a look at the web version here.

So recently I was thinking about it again and managed to plug some of the formulas into a Processing sketch:

Poi spinning emulation – first attempt.

I have always enjoyed emulation software for juggling, it’s amazing what you can do – juggle 100 flaming swords for example (or make an LED juggling emulator, like this one I made) Anyway, it turns out that there isn’t anything similar for poi spinning.*

Seems like there should be one.

*UPDATE: turns out there are quite a few. Thanks Reddit! Here is one of my favourites, done in Processing: http://www.kaiein.com/poi_auto_sim/

**UPDATE 2: Danny Thomas from kaien.com kindly let me use the code for my own emulator – I’m using this as the base for a new single colour version of “Magic Poi”, “Magic Poi Basic”. See the demo here: http://magicpoi.circusscientist.com/basic

Upgrading K8 IR RGB Clubs

I love K8. Their reasonably priced LED equipment is the basis for my favourite solo juggling act, the “Electric Glow Juggling Show”. I bought my K8 clubs over 7 years ago, and last month they finally died.

Emergency!

Since the pandemic finished (or at least since we all learned to live with it) I have never been busier. People want to book my shows. Luckily, a friend has some working K8’s I can borrow for now, but long term I need to sort this out. I’m not changing manufacturer so the choice is to either purchase a new set or fix the ones I have. The pandemic also had the effect of limiting my finances for the past two years, so new purchases are on hold for now – so I opened up my K8’s to see what can be done.

Inside the K8 clubs and balls

First impression: these things are well put together. It took me the better part of an hour to get the electronics out without destroying the club in the process. I found the problem: a really fat lithium battery, completely finished.

Then I found something really interesting. The actual circuit is pretty straightforward and is running on a replaceable Attiny chip. So a few years ago I made some code for Arduino which was an attempt to emulate the K8 IR RGB internal workings. With a few adjustments this old code actually works inside of my favourite clubs – it was as simple as matching the alignment and dropping in my own chip. Thank you K8 for not soldering your chips on, and using a header instead!

The plan

First priority is to get the replacement batteries – I ordered these ones on Amazon: the same size as the original but bigger (>2x) capacity. Should be great if they work!

In the meantime I am working on the code, with upgrades such as variable strobe (like Aerotech equipment), and timed record and playback of settings for my show*.

*I understand that K8 have implemented a method of record and playback functionality in their latest equipment, as well as more new settings – if you need LED equipment I highly recommend going there and getting some. Also, their customer service is brilliant. https://k8malabares.com/

Here is a sneak preview of a new setting running on the bare circuit – Red/Blue with variable strobe!

If anyone is interested, the code is up on Github here – most of it is from many years ago and not very good, but I am working on it, need to have everything working without bugs by the time I receive the batteries. After I upgrade I don’t want to have to open the clubs again! When I get everything working I will do an “instructables” style tutorial – even if you aren’t interested in the firmware upgrade, the battery replacement is worth doing to extend the life of this amazing equipment. By the way, one of my K8 balls stopped working ages ago – I just opened it up and the battery is replaceable too!!

The Circus Scientist Show

In my day job I often do circus shows at schools, for fun days and end of year events. Having had this experience over many years, I am proud to introduce a new school show focusing on technology.

The Concept:

This is a motivational show aimed at school kids. The purpose of the show is to showcase some amazing tech with the goal of inspiring children to consider a career in technology.

Topics:

Fun with electronics and programming, featuring WiFi controlled LED’s, a full-screen projector display and interactive audience participation.

Technologies:

I plan to demonstrate the Raspberry Pi (with Scratch and Processing), Makey Makey (Banana piano and some of my own creations) and some Android apps for WiFi control, as well as Arduino programmed electronics projects.

It’s becoming easier to be a programmer but at the same time there is so much choice – I will be showcasing some of the most accessible learning technologies I have found in a fun, interactive way, via a live stage show.

Check out http://show.circusscientist.com *concept website, under development. The actual content, duration and pricing is subject to change. ETA early 2023.

K8 Virtual Juggling with working remote

K8 are my favourite type of LED juggling equipment. Recently I updated my virtual juggling web app to include a working remote control – just like the real thing.

The App

So the app consists of an animated juggler, a remote control and “Change your pattern” button.

While the juggler is juggling, you can press buttons on the remote to change the juggling ball colours (accurately emulating the actual K8 equipment settings)

The “Change your pattern” menu is a large list of different juggling patterns, which when selected will change the animation displayed.

How it works: back end

The back end is based on Flask. I am using the beautiful soup library to fetch the menu of juggling patterns from the awesome library of juggling website. Once selected, the gif of the pattern is fetched. It is then processed (a script inverts the colours and makes the juggling balls transparent) – if that hasn’t already been done for the particular pattern.

How it works: front end

The juggling animation and remote control are written with P5.js. The juggling ball colours are implemented as a background which shows through the transparent balls. The button co-ordinates are relative, so work on any size screen (looks best on Desktop)

Magic Poi 2022 update

Current state of Magic Poi – and some ideas for the future.

First of all, an announcement: Magic Poi is now available for ESP32, as well as ESP8266 architecture. This will bring improvements in performance. I plan on continuing support for both, and in the near future a combined code base will be provided.

I am going to list current features here, and improvements I plan to implement.

On-board images:

  • I have partnered with EnterAction, an awesome Sydney based fabrication company who are taking over the hardware development from now on. Improvements will include an SD card add-on for limitless on-board storage. This will require changes to the code, as currently the maximum is 52 images supported.

UDP streaming:

  • this is a defining feature of Magic Poi. The images are generated off-device, and “streamed” via UDP pixel by pixel. I plan to keep improving this functionality but change it to not be the default mode. Due to WiFi interference the UDP stream is sometimes interrupted, making the LED’s stutter, so work is being done to mitigate that.

“Timeline” – images changing in time to music:

  • currently there is a desktop app to generate the timeline (and associated images) and save as a zip file, which needs to be uploaded to the Android app in order to be “streamed” to the poi. I plan on changing this functionality to rather happen in the poi code, thus avoiding the WiFi interference problem. The timeline editor will be made into a web app, with the option to download directly to the poi.

Station mode:

  • poi connected to a router provides more stable WiFi than the current AP mode. I have made a start on providing a way to use this mode.

Online account:

  • like a PlayStation or Kindle, there is a benefit to having a cloud aspect to any product that consumes media. The Magic Poi website is going to be a place where you can upload and share images and timelines, as well as interact with other poi owners. All uploaded images will be private of course, unless shared. I have made a start on this cloud aspect, with an option in testing to download images directly from your cloud account to the poi. The ultimate goal is to be able to sync any two pairs of poi with two clicks!

Android app:

  • Still not working: text to image (stream words directly to the poi).
  • Once the online portal is finished, this will be added to the app, so shared images and timelines can be viewed without need for a web browser.

The above is a small part of the list – thanks to EnterAction taking over the hardware development side, I will have more time to devote to the software improvements. We also plan on adding a battery level indicator, and a higher power battery for more play time.

Thanks for reading!

Keep an eye on this blog, and sign up to the newsletter (if you haven’t already) for more updates as Magic Poi moves forward towards it’s inevitable crowd funder launch!

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Unpacking an inverted index with Python

Lately I have been doing a lot of data processing in my job for UCL. I recently came across a problem which didn’t have a ready made solution, so here is my take on it.

Inverted Index

An inverted index is simply a list of all the unique words in a document, labeled by their position. Something like {‘Hello’: [1], ‘world.’: [2]}. Except that they are rarely in order and there can be multiple instances of any given word in a document.

I was given the task of ‘unpacking’ one of these (actually thousands, but if you can do one..). The inverted index came in the form of a dictionary of words and their positions, returned from an api call. Since I couldn’t find a ready made solution, here is my take on it, in Python 3.

The solution

You can try it out with the included example. I hope this helps someone with a similar problem to solve – do let me know in the comments if you have a different solution.

I made an LED indicator for my portfolio site

Job hunting is tough – I’m busy until February 2022 but already feeling anxious about finding the next gig. That’s why I wanted to give myself a bit of an incentive – a visible indicator of success. I decided that whenever someone visits my portfolio site, I wanted an LED to light up. Read on to find out how I did it (using Flask, http requests, and an ESP8266)

Self Hosting

I recently had a bad experience with an online service shutting down on me – had a bit of a rant about it, although in the end it wasn’t too serious – but I am now determined to do self-hosting wherever possible *disclaimer: my current work project is hosted on Google Cloud, and I’m using Firebase and push services for some Android apps also.

The Flask api

The first step was to create a simple Flask api to facilitate tracking of site visits. This is based on this minimal flask api template on GitHub. I used a simple global variable to keep track of website visits because I’m doing this in my spare time and because it works fine – and I love boolean switches. Here is how it works in one simple gif:

Think of the hand as a visitor to my site, and the “switcher offer” is the ESP8266 at my home checking the api (the switch)

HTTP request from resume site

Since I am learning React my portfolio site was a good way to have another look at the framework. I used this single-page React resume site template as a base, adding my own details and an http request to the Flask api endpoint on load.

ESP8266 code

I used the basic http requests example with my own api details, and added in EEPROM code to record the incrementing number of visitors to persistent memory. The ESP8266 module checks once per second with the api whether there has been a new visitor to my site. If there has, the built in LED on my D1 Mini switches on. Although I have mostly moved over to using PlatformIO, for this very simple sketch I used the Arduino IDE.

Deployment

Like I said, this one is self-hosted. I’m using Digital Ocean droplets, which are a fixed cost of 5 dollars per month, for as many sites and services you can cram on there (trust me, it’s a lot). The React site was surprisingly simple to deploy, just build, copy the build folder and point Nginx at it. Flask is a little bit more complicated, compared to how easy it would be on Google Cloud, for example, but a few config files are really not too much to handle.

The result

Whenever someone visits my website, the LED lights up. Simple as that. And I can plug in and check how many visitors I have had. I’m hoping that one of those visitors will like what I do enough to hire me next year!

Visit my site https://devsoft.co.za to light up my visitor tracking LED.

Potential improvements

If I was making this into a product, I would certainly upgrade the Flask API to include a database to keep track of the number of visits, rather than doing this on the ESP8266 EEPROM – which maxes out at 255!* Obviously this could include a web interface for accessing the information, I could log the times… But most of this tracking stuff has been done already – analytics for websites. Perhaps the ESP8266 could pick up some of this information and display it on an LCD screen. A flask service for accessing Google Analytics from Arduino perhaps? Let me know if this is something you are interested in!

Also, proper authentication – if this wasn’t just for myself… JWT, rate limiting, CRUD endpoints and a web interface to change LED behaviour.

And maybe an RGB LED would be nice, then I could add in some of my other websites, in different colours!

*apparently the Arduino EEPROM library works differently on ESP8266 – ignore that part of the code, I need to update it (the counter still increments while the module is plugged in, though)

Goodbye Fritz.ai, goodbye proprietary online services

Fritz.ai “sunsetting services”:

Fritz.ai is (was) a cool service for, in particular, making machine learning apps easily. The marketing hype was slick, and they roped in a lot of developers to help them push their service to many devs, particularly in the Android space, with paid articles on medium, and on their website.

First of all, I have to say, I take full responsibility for this, and I don’t blame anyone at Fritz.ai for my problems, it’s their service, they can do what they want – but I wasted a lot of time learning how to use their api, publishing my own (unpaid, no affiliation) posts about the service, and using it in apps published to the play store. Their business model seemed clear – free to use but once you reach a threshold you have to pay for the service. Seems legit, probably was legit.

My Android apps didn’t take off, so I never reached that threshold, never ended up paying for anything at all – but I did waste a lot of time making apps using a service which is getting switched off at the end of the month (August 2021). In other words, my apps are going to be switched off, for the (very) few users who did install them. If I want to continue with these apps, they will need a substantial re-write. In many ways I’m lucky that the apps were not successful!

So I have learned a valuable lesson here:

The lesson is: don’t trust your work to “flashy” or “new” products and services. I could have spent a week back then just learning the ins and outs of tensorflow on android, and done it myself. Just because I’m lazy doesn’t mean I’m stupid. Lesson learned.

*here is the full unedited email for those who are interested – I still don’t see any mention of this on their site or blog:

We’re Sunsetting Fritz AI

Service will end August 30, 2021

Hello,

This email is to let you know that we will be sunsetting the Fritz AI mobile machine learning platform, effective August 30, 2021.

What does this mean for my account?

As always, any custom trained models, datasets and annotations are exportable. Please see this documentation for how to export datasets and models.

After the sunsetting date, access to the Fritz AI SDK, webapp, API, and hosted services will be discontinued. All models, datasets, and resources stored in Fritz AI will be removed.

For mobile apps, the Fritz SDK will lose API connectivity, but on-device model inference should continue to function. Regardless, we advise you to update your apps, removing the Fritz SDK and models.

Snapchat lenses do not depend on the Fritz SDK nor API, and lenses should continue to function as before.

Why are we doing this?

Fritz AI’s mission has been to make the power of machine learning solutions available to mobile developers. When we started in 2017 there were few options available. In the following years there have been many great entries to the market such as ML Kit, Create ML, MediaPipe, Lobe.ai, MakeML, Firebase ML, and more. Now there is a mature ecosystem of tools, including free and open source options.

We understand that this decision will have significant consequences for our community, but we truly believe the wide range of incredible tools and resources out there will empower you to continue on without Fritz AI.


Sincerely,

Dan & Jameson
Founders, Fritz AI

Magic Poi Magic

SmartPoi is re-branding as MagicPoi

Magic Poi online portal
Magic Poi login screen

New stuff:

Check out http://magicpoi.circusscientist.com to sign in to the new experimental online portal. A place to upload and share poi images. I am working on a way to get the images directly onto your poi, straight from the server. If you have access to a linux terminal, you can test this using curl: curl http://magicpoi.circusscientist.com/api/get-filenames for a list of files in .bin format. Or just visit the link here to see all the files listed in a browser: http://magicpoi.circusscientist.com/api/get-filenames

To download a specific file you need to send a get request to the api like so: curl -X GET http://smartpoi.circusscientist.com/api/output/e5d2dd82008b343354a0f37ab435c32aab9dc132.jpg.bin -O -J -L $url – which will download the file and save in the current directory. Now that the api is set up, I have working poi code to get and display the images directly from the poi, so will be sharing this on GitHub once it is cleaned up a bit.

Oh and I finally managed to get the images to work right-side-up! So no more need to rotate 90 degrees before uploading.

coming soon:

There is a lot to do still, both on the server side and in the poi code. I recently switched over to PlatformIO, as the huge code base was getting a bit unwieldy for Arduino IDE. This is going to mean a huge re-write of everything, but will give me an opportunity to enhance things along the way, such as:

  • Built in web server on the poi, able to switch between Online and Offline modes, including access to the magicpoi.circusscientist portal (so you will be able to control and manage the poi operation from any browser) – I tried this already, the magicpoi site works in an <iframe>, and there are many open source libraries for the access point management.
  • Many utilities such as creating timelines, image generation, text to image etc on the magicpoi portal. Also a better user interface (looking at javascript gallery plugins, but first getting the basic functionality up and running)
  • Much easier poi sync and multi-poi control using mesh networking
  • Support for more poi sizes (72px is currently the default on the portal – or was it 80px?)
  • ESP32 support – this is inevitable, unfortunately my only ESP32 device broke, so this is on hold for now.
  • Many other hardware improvements being worked on (thanks Caleb!) such as accelerometer, ESP32, external flash, smaller embedded LED’s, battery management and more.

some notes:

The online portal is “alpha” quality, so please expect things to break. I have limited the image uploads to 10 per account, and the .bin files (for imaging on the poi) are all kept in one public folder for now, so please don’t upload anything personal or proprietary at this point. This is just for ease of use, as I haven’t set up security end-points for the poi – server connection. Passwords are hashed, however, so at least that much is secure (this means even I can’t see your password), and the server is kept up-to-date with security updates.

So what do you think about the Magic Poi project? So many people have emailed with stories and photo’s of their test builds, it’s hugely motivating, so thanks everyone, you know who you are! I need to do a blog post with some of the images I have received, many different versions of the poi being built and spun all over the world – will have to get permission from the individuals concerned first though.

It’s slow but steady progress, and I am getting more certain over time that Magic Poi could be a serious contender in the LED poi space eventually. At least in kit form, on Indigogo!

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The magic of open source

Recently I found an awesome Android retro-gaming app – Super Retro Mega Wars, available on F-Droid. I was excited to introduce my son to the fun of Asteroids, Tetris, Snake and Tower Defense. Unfortunately the difficulty level was beyond a 7-year-olds’ abilities, and he soon lost interest.

All of the apps on F-Droid are open source, though, and I am an Android developer. Let’s see what I can do, I thought.

A few minutes later: I am pleased to present a kid friendly version of “Super Retro Mega Wars”, you can check it out here – Retro Wars Kid Friendly Version.

Changes include:

  • Asteroids: instead of blowing up, the space ship destroys asteroids it touches
  • Tetris: blocks and lines only
  • Snake: slowed down to a manageable speed
  • Tower Defense: more missiles and bigger explosions

All of this took me a total of around 10 minutes to set up, despite the app being coded in Kotlin (I am still transitioning from Java). Mainly this is due to the very clear way that the code is presented by the author – thank you @pserwylo, my son loves your game.

This brings me to the point of this article. Open source is amazing. It gives joy and empowerment to people from around the globe. There are loads of important projects out there that have a huge impact by being freely available and editable. Even a simple game app can make a difference – I know the source of this one is going to help me become a better developer.

I only wish the same could be said for vaccines. Imagine a world where we could say that scientists gave away their recipes with the hope that others could use and build on their work*.

*I am aware that many do, just none that I am aware of who are involved in producing the current commercially available Covid-19 vaccines.**

**Thought provoking further reading: https://jacobinmag.com/2021/02/finland-vaccine-covid-patent-ip/ – I have no affiliation, just an interesting article about a failed attempt at making an open source Covid-19 vaccine in Finland.