We’re always fans of interesting clock builds around here, whether it’s a word clock, marble clock, or in this case a clock using a unique display method. Of course, since this is a build by Hackaday’s own [Moritz v. Sivers] the display that was chosen for this build was a custom thermochromic display. These displays use heat-sensitive material to change color, and his latest build leverages that into one of the more colorful clock builds we’ve seen.
The clock’s display is built around a piece of thermochromic film encased in clear acrylic. The way the film operates is based on an LCD display, but using heat to display the segments. For this build, as opposed to his previous builds using larger displays, he needed to refine the method he used for generating the heat required for the color change. For that he swapped out the Peltier devices for surface mount resistors and completely redesigned the drivers and the PCBs around this new method.
Of course, the actual clock mechanism is worth a mention as well. The device uses an ESP8266 board to handle the operation of the clock, and it is able to use its wireless capabilities to get the current time via NTP. All of the files needed to recreate this are available on the project page as well, including code, CAD files, and PCB layouts. It’s always good to have an interesting clock around your home, but if you’re not a fan of electronic clocks like this we can recommend any number of mechanical clocks as well.
9 thoughts on “Using Heaters To Display Time”
A very long time ago, I tried to do something similar using the standard “white turning transparent” thermochroic paint. I failed miserably. Nice to see someone make something that worked!
Finally a clock for predator.
Then will this be miniaturised so the poor chap can have a nice new watch? Second thoughts, no need, he was viciously murdered by the a previous governor of California.
Nice clock, but with Arnie smiting the client list, might be limited to selling it to snakes, who could put their mouse hunting senses to a new use. No fingers to set the time though.
plot twist: the segment displays are highpower LEDs shining into the black backside of the thermochromatic pate :D
I wonder if you could make a display like this faster by using small thermoelectric modules instead of resistors. That way you could cool the color-changing film quickly by reversing the polarity of the module.
In the 2nd paragraph they mention that a previous larger iteration used peltier junctions to do exactly this.
Cool, um I mean hot, not I mean, um, ah… luke warm? Confusing but fascinating.
Amazing! I have one in the making since ever https://hackaday.io/project/171912-thermochromic-paint-clock it uses black/white thermometric pigment. Hope to finish it, someday, maybe :P
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