For a recent Element14 Presents video, I wanted a device that represented a modern voice assistant, “A black box with an LED on the top”, a HAL-exa.

So I modelled a simple round box that could be printed in multiple parts; rim, base and body. These were printed on the 3D printer and the spray painted in black and silver. The dome was from a broken LED light.

It is barely noticeable in the video but there is also a HAL-9014 sticker on the front of the case.

I used a high wattage LED driven from a transistor and a Seeed Studio XIAO SAMD21 microcontroller to drive that. The code was a modified version of the fade example from Arduino. A slight gotcha with the Xiao was that pin 1 is a true analogue pin. So when you do an analogue write it produces different voltages, not a PWM signal like the other pins. That’s a great feature if you want to generate audio output. This foxed me when my fade was not working, I got a blink instead. Swapping to a different pin solved the issue.

As you’ll see in the video the HAL-exa is only shown for a few seconds at the start. You’ll also see some of the steps necessary to build your own DIY Voice Assistant.

One thought on “HAL-exa

  1. Moss says:

    The elders of the internet would certainly approve of the use of a circular red light.

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