IocTober Day 18 - Open All Hours

We’re creating an IoT solution for every day of “IocTober”.

One drawback of having a headquarters that combines office and studio space with our electronics and mechatronics workshop is that visitors presume that the position of roller-door signifies our office hours. We do lower our rollerdoor during the day when wind or rain threaten to turn “breezy and naturally lit” into “miserable”.

More than one visitor has said “I came by earlier but it looked like you were closed”.

So, we need a way to remind visitors that yes, we are here.

LED matrix signs are nowadays quite easy to work with. In days past matrix controllers were expenive and arcane, but these days there are just a couple of well supported ways to interface with matrix panels. You may have noticed that outdoor LED advertising signs are rapidly replacing all roadside and building-mounted advertising billboards.

In this case, we wanted a simple “Open” sign to place in the window, so we selected some panels using the WS2812 serial LED chip (there are other options which are more complex to control, but faster, even permitting full motion video). To protect against cases where we forget to alter the sign, it reads the state of the front door lock; simply put, door unlocked means we’re open.

The versatile Adafruit GFX library now supports led panels

We (ab)use a magnetic reed door opening sensor to read the position of the lock, and then our sign subscribes to changes in the lock status.

  • Door unlocked => OPEN
  • Door was locked in last 30 mins => CLOSED
  • Door was locked longer than 30 min ago => OFF
  • Door unlocked after 7pm => YIKES YOU FORGOT TO LOCK UP. OFF, and send an alert.

And that’s the IoT in a nutshell - getting computers to handle the details so that you don’t have to.