Explanation

I designed this to be a project kids (probably middle schoolers) could follow to learn soldering and programming. There are a lot of kits available, but they lack the ability to teach kids to make their own projects and largely run like copy and paste projects. This project includes the code and related files to make a binary clock with a Micro:bit. Versions 1 and 2 will work with these.

The Makecode works by taking the time from the RTC module (see below for the part) and then displaying it via the neopixel library. The "On Start" block sets the initial parameters and displays a rainbow, mainly as a check to ensure that the LEDs are connected. Two forever blocks run to (1) obtain the current hour, second, and minute values and (2) display the values in binary format through the neopixels. The work of getting the time and assigning values to the LEDs is done through the defined functions.

The Micro:bit buttons are configured so as to allow the user to (1) toggle between daylight savings time ("DST") and non-DST, (2) toggle between the "1" LED colors, and (3) change the brightness. Press A+B to toggle DST. Pressing A or B alone will toggle brightness and colors.

IMPORTANT Make sure to remove the functions to set the time in the On Start block after you upload the program to the DST module. Otherwise, the time will continue to reset each time the Micro:bit is reset.

The Micro:bit runs on 3.3v, but the neopixels can run on 5 volts. Since 5 volt power supplies are common, I opted to run the clock on a 5 volt supply and power the Micro:bit through the regulator module. I run mine on a 3 amp supply.

Electronic Components

Through-hole components for the project uses a DS3231 real time clock ("RTC") module, an AMS1117-3.3v voltage regulator breakout board, a single pull double throw slide switch, and a barrel jack connector. Those parts are generally available from Amazon/eBay/Aliexpress/Banggood. The last through-hole component is a Micro:bit breakout board from Sparkfun. Kids should have no problem soldering these. You should obviously check the dimensions of the parts you purchase. Other than the switch and the barrel jack connector, the parts have 2.54 pitch pinouts.

The LEDs are WS2812B-2020 modules. These do not need resistors or capacitors. I purchased mine through LCSC. The data sheets suggest that the modules are somewhat fragile, but I soldered mine with solder paste and a hot air station set to 300 degrees celsisus. Consult the data sheet about soldering.

Housing

I designed the housing in Freecad. The top piece (with the holes for the LEDs) should be printed with supports. I used an Ender 3 Pro with minimal modifications. I had to remove a slight amount of material from the holes in the top piece where the pegs on the bottom part insert. Results will depend on your printer's calibration. I glued the parts together with Gorilla Glue. I then used Rustoleum filler primer spray to fill any layer lines or other imperfections. After the housing, I painted it. Most paints should adhere to the Rustoleum spray.

Finally, I used M3 brass inserts in the holes where the circuit board sits. As is, the M3 screws went in fairly easily. The inserts are readily available online. The PCB is held in place by screwing it in to the brass inserts.

Printed Circuit Board

I designed the printed circuit board ("PCB") in EasyEDA and had it fabricated by JLCPCB. The EasyEDA software is fairly easy to use and should be for most kids. The Gerber has been uploaded here.

Default Content from Microsoft/Github

Open this page at https://filledmilk.github.io/microbit-binary-clock/

Use as Extension

This repository can be added as an extension in MakeCode.

• open https://makecode.microbit.org/
• click on New Project
• click on Extensions under the gearwheel menu
• search for https://github.com/filledmilk/microbit-binary-clock and import

Edit this project

To edit this repository in MakeCode.

• open https://makecode.microbit.org/
• click on Import then click on Import URL
• paste https://github.com/filledmilk/microbit-binary-clock and click import

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Metadata (used for search, rendering)

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