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