Summary of USING ARDUINOS TO DRIVE UNDOCUMENTED DISPLAYS
This article details a project by [mircemk] repurposing a vintage vacuum fluorescent display (VFD) from a POS terminal into a weather forecasting station. By identifying RS232 communication pins on the original microcontroller, the builder interfaces the VFD with an Arduino. Instead of using external APIs, the system utilizes a sensor suite to measure barometric pressure and generate a 12-hour forecast inspired by analog Zambretti devices, demonstrating how to drive undocumented displays for custom applications.
Parts used in the Weather Forecasting Station:
- Vacuum Fluorescent Display (VFD) from a POS terminal
- Arduino microcontroller
- Sensor suite for measuring barometric pressure
For those of us old enough to remember the VCR (and the difficulty of programming one), the ubiquitous vacuum fluorescent display, or VFD, is burned into our memories, mostly because of their brightness and contrast when compared to the superficially-similar LCD. These displays are incredibly common even apart from VCRs, though, and it’s easy to find them for next to no cost, but figuring out how to drive one if you just pulled it out of a 30-year-old VCR is going to take some effort. In this build, [mircemk] shows us how he drives unknown VFD displays using an Arduino in order to build his own weather forecasting station.
For this demonstration [mircemk] decided to turn a VFD into a weather forecasting station. First of all, though, he had to get the VFD up and running. For this unit, which came from a point-of-sale (POS) terminal, simply connecting power to the device turned on a demo mode for the display which let him know some information about it. From there, and with the knowledge that most POS terminals use RS232 to communicate, he was able to zero in on the Rx and Tx pins on the on-board microcontroller and interface them with an Arduino. From there it’s a short step to being able to output whatever he wanted to this display.
For this project, [mircemk] wanted the display to output information about weather, but rather than simply pull data from some weather API he is actually using a sensor suite connected to the Arduino to measure things like barometric pressure in order to make a 12-hour forecast. The design is inspired by old Zambretti weather forecasters which used analog wheels to input local weather data. It’s an interesting build not only for the VFD implementation but also for attempting to forecast the weather directly with just a tiny sensor set instead of downloading a forecast to display. To do any better with your own forecasts, you’d likely need your own weather station.
Source: USING ARDUINOS TO DRIVE UNDOCUMENTED DISPLAYS
- How did the author get the VFD up and running?
Connecting power to the device turned on a demo mode that provided information about it. - What communication protocol do most POS terminals use?
Most POS terminals use RS232 to communicate. - Which pins were identified to interface with the Arduino?
The Rx and Tx pins on the on-board microcontroller were identified. - Does the project use a weather API for data?
No, the project uses a sensor suite connected to the Arduino instead of pulling data from an API. - What specific weather variable is measured to make the forecast?
The sensor suite measures barometric pressure. - What type of forecast does the system generate?
The system creates a 12-hour forecast. - What inspired the design of this weather forecaster?
The design was inspired by old Zambretti weather forecasters that used analog wheels. - Why might you need your own weather station for better forecasts?
To do any better with your own forecasts, you would likely need your own weather station.
