3D Printing

Puck.js Duplo Block Police Siren Build

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soldering iron, pexels

I picked up a Puck.js a while ago and after trying out a few basic bits of code, sadly let it start to gather dust on my shelf. That changed this weekend as I browsed the sample project listings for something simple to build, picking up the Puck.js Duplo police siren build to try.

It should be a fun toy for my youngest to play with, as he really enjoys Duplo.

What is the Puck.js?

puck.js duplo build start - the puck.js out of it's case.
The Puck.js and it’s button case.

The Puck.js is an open source JavaScript microcontroller. It has a variety of features such as:

  • Button
  • Magnetometer
  • Accelerometer
  • Gyro
  • IR & RGB LEDs
  • Temperature and light sensor
  • FET output
  • Programmable NFC tag
  • 9 IO pins

The best part about the Puck.js for me is how accessible it is to run and deploy code to. Using Web Bluetooth and it’s included puck.js library, you can write code in a Web IDE, connect over Bluetooth, and have your code running in seconds.

Building the Puck.js Duplo Police Siren Project

If you want to try it out yourself, the actual tutorial page itself is the best resource to begin with. There is a video available there to follow along with.

Here is the Thingiverse page where you can get the model. It currently only lists a scad version of the file, so you’ll need to download OpenSCAD and open it there.

Here is a gist for the file including the cut-out operation that subtracts the innards from the block to make room for the puck.js and piezo to fit into.

I printed the block using my Elegoo Mars resin 3D printer. My first go seems to be slightly loose fitting, so I might shrink the model to 99% size and try again for a second iteration.

I used a new resin that is meant to be easily rinsed/washed after printing with water. The quality on the top of the block doesn’t look as good as usual, so I’m not sure if this resin is to blame for that or not.

puck.js duplo block 3D print

Connecting the Components

The LEDs connect to D1/D2 and D30/D31. The piezo goes on D28/D29. I used RGB LEDs, so I snipped the other legs off, leaving just the blue and common cathode terminals to connect up.

After a bit of dodgy soldering, it works!

Installing Everything Into the Block

With a little bit of coercion, the whole lot fits in. I used a bit of hot glue on four edges of the Puck.js to keep it in place, but keep it easy to remove if needed.

After that, I added a layer of scrap paper with the piezo in-between, and glued that in too.

Here is the final result.

The Puck.js may be fairly pricey, but it includes a lot of IO. It’s battery and use of Bluetooth LE make it ideal for projects where battery life is a concern. The battery is super cheap and can last up to around a year if used carefully.

I had fun making this project. It’s a great project to get started with the Puck.js, and hopefully I’ll find some more use cases soon where I can use more of these great little devices.

3D Printing Useful Parts

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water tap design perspective view from fusion 360

I purchased my first 3D printer about 6 months ago after having putting the idea off for a year or so before that. For a while now I’ve had a fascination with being able to use 3D printing for hobby projects and bespoke creations.

From purchase until just recently I had only been printing 3D models for fun. Figurines, Star Wars replicas, and other random items. I even printed a Millenium Falcon (in two halves) and painted it for my oldest son.

After printing these pre-made 3D models, my oldest son and I sat together and created a simple ‘dropship’ model in Blender which we also printed.

These have all been a lot of fun, but after a while I had a hankering to use the 3D printer for some good around the house too.

3D printing useful parts

The printer I am using is the Elegoo Mars. It uses UV photocuring technology to print models out of a liquid resin. The printing plate lifts up from the resin basin and UV light is shone from underneath, emitted by an LCD panel. This cures the resin on the print plate one layer at a time.

elegoo mars uv lcd resin printer

The main benefit of this compared to FDM printers is that you can get a really good level of detail (resolution). One of the bigger downsides to this however is that the cured resin is more brittle.

The Elegoo Mars was a very cheap entry point for me to get started and I’m happy with the limitations (especially when considering the great detail that is achievable).

Printing a fake water tank handle

The reason I had this idea was to put in a fake water tank handle for our outdoors water butt.

Our 1.5 year old is currently a huge fan of running water and has learned how to open this tap and drain our collected rain water. One option would have been a lockable cover to go over the tap handle, but why do that when you can create your own solution?

I pulled out the tap handle and observed how it lets the water out when turned. Basically the tap handle shaft has a circular cut out on one side. Turning this aligns the hole with the opening in the water tank and allows water to flow through. Turning it further closes the hole again.

The ‘fake’ tap handle solution is pretty simple, replicate the part, but close the hole in the shaft.

Design

I’ve used Blender for more creative projects in the past, but decided to move onto something more suited for CAD and 3D printing. A friend recommended Fusion 360. After trying it out for this project I can highly recommend it.

It allows you to design your parts in stages. If at some point you want to reconfigure the design and change measurements, the process is simple. You go to that stage, apply the new measurement, and the software will ‘replay’ that through the remaining stages. Your whole design adjusts accordingly.

top view of the design
water tap design in fusion 360
The water butt tap design with no hole in the central shaft

Result

The resulting print shown below is actually the second iteration. The first design I made didn’t have a strong enough handle.

Here is the ‘fake’ water tap 3D print in action.

In the video above you can see the water tap in action. Turning it to any angle keeps the water flow blocked now. On the ground you can see the original water tap which is now just simply kept out of reach for when we actually need to use the water.

It is possible to pull the fake tap out as you can see above, but for a small toddler it is not easily possible. In order to keep it water tight, I had to get the measurement just right so as not to leak, but also not be too tight to remove again.

This is post #6 in my effort towards 100DaysToOffload.