Much to the chagrin of many living in North America who still need to do things like keep two sets of wrenches on hand, most of the rest of the world has standardized to a simpler measurement system using metric units exclusively. The metric system is widely adopted worldwide, but we still use a base-60 system for timekeeping that predates the rest of the metric system. The French did attempt to “decimalize” timekeeping as well with the French Republican Calendar at around this same time, but this “metric” timekeeping system never caught on particularly well. It’s still an interesting historical tidbit, and [ClassTech] built this modern metric clock to explore it a little more.
The system itself uses ten-day weeks, ten-hour days, and 100-minute hours which makes it more in line with the base-10 system common to the rest of the metric system. But this means that a second in the French Republican system actually works out to a little less than one and a half SI seconds, meaning that a modern timekeeping computer needs to do a little more math to display the correct time at the correct interval. [ClassTech] is using a Particle Photon IoT processor getting the time from a NTP server, converting it to “metric time”, and displaying the time on a Nextion touch display.
While the device is reported to update the time once per second, we’re not sure if this is every SI second or every French Republican second. Either way, there are plenty of reasons this timekeeping system never gained widespread adoption, and a surprising one is that timekeeping tends to be easier in a base-60 system due to its capability of having more divisors. Many other reasons are less technical and more cultural, and timekeeping tends to be surprisingly difficult to coordinate even among shared numbers systems and languages.
Old-school rail monitoring systems had amazing displays of stations and tracks covered in flashing lights that tracked the progress of trains along a route. While it’s unlikely you’ll fit such big iron from the mid-20th century in your home, you can get a similar aesthetic with [Kothe’s] interactive subway information display.
The display relies on an Arduino Mega 2560 Pro Mini as the brains of the operation. It drives strings of WS2812B LEDs which correspond to stations along the various metro lines in the area. Additionally, the microcontroller drives a 4.3″ Nextion LCD display. The Nextion displays have the benefit of acting as a self-contained human machine interface, running their own controller on board. This means the Arduino doesn’t have to spend cycles driving the display, and the Nextion hardware comes with a useful software package for quickly and easily designing GUI interfaces. For further feedback, a DFPlayer MP3 module is used to allow the system to playback prerecorded voice samples that provide information on the rail system. The attractive front panel is made with lasercut acrylic and a color printed acetate sheet.
It’s a build that bears striking similarity to real rail information systems fielded by railways around the world. We can imagine such a device being particularly useful in a backpacker’s hostel or university dorm to help those new to town find their way around. If you prefer a more stripped-back aesthetic, we’ve seen a barebones PCB build done as well. Video after the break.
Continue reading “Interactive Subway Map Talks You Through The Route”
Monitoring your home’s energy use is the best way to get a handle on your utility bills. After all, you can’t manage what you can’t measure! The only problem is that most home energy monitoring systems are cumbersome, complicated, or expensive. At least, until now. [Kevin] has created a new electricity meter based on Particle Photons which should alleviate all of these problems.
The Particle Photon (we get confused on the naming scheme but believe this the new version of what used to be called the Spark Core) is a WiFi-enabled development board. [Kevin] is using two, one to drive the display and one to monitor the electricity usage. This part is simple enough, each watt-hour is accompanied by a pulse of an LED on the meter which is picked up by a TLS257 light-to-voltage sensor. The display is a Nextion TFT HMI (touch screen) which is pretty well suited for this application. The data is corralled by emoncms, part of the OpenEnergyMonitor platform, which ties everything together.
For a project that has been done more than a few times, this one does a great job of keeping the price down while maintaining a great aesthetic. Make sure to check out the video below to see it in action.
Continue reading “Simplest Electricity Monitoring Solution Yet”