[Coyt] wanted a more convenient way to keep up to date with the ever-changing Bitcoin exchange rates, as well as weather and other useful information. He realized that the vacuum fluorescent display (VFD) he had purchased a couple of years ago would be perfect to display small amounts of information.
[Coyt] discovered that the VFD had a serial interface. The problem was that the VFD was looking for a 12V serial signal but the Raspberry Pi he wanted to use runs at a 3.3V. Upon closer inspection [Coyt] discovered that the VFD actually ran at lower levels as well, but it had a level converter chip installed in front of the main connector. He simply bypassed the level converter and was then able to get the RasPi speaking directly to the VFD.
The brain running this display is a Raspberry Pi. The Pi runs a Python script that pulls down all of the relevant information from the internet and displays it on the VFD. [Coyt] didn’t stop there, though. He knew that having the screen on all of the time would be somewhat of a waste, so he hooked up a PIR sensor to automatically turn on the display only when needed. The PIR sensor can detect motion in the room and will disable the display after a set period of inactivity. Most of this is powered by an LM7805 voltage regulator. While [Coyt] admits a linear regulator is not his ideal solution, it does get the job done. The metal stand acts as a nice heat sink for the regulator.
[Coyt] also wanted his project to have a certain aesthetic. He started by bending a metal plate into a stand for the electronics. He then mounted the VFD on the front of the stand and the RasPi on the back. He also mounted green LEDs between the two plates to light up the edges for a little extra pizzazz. [Coyt] believes he can use the RasPi to PWM the LEDs but this has not yet been implemented. This would allow him to pulse the light for added effect.
Since the whole thing is run by a Python script, it would be trivial to modify it to display other kinds of information. What would you do if you had a motion sensitive automatic ticker?
That is deceptively big
A motion sensitive automatic ticker? Isn’t that your heart? ;-)
Mines a little diffrent http://m.imgur.com/a/yxR8d Actually its even more different then back then now (the API and site has also changed) if anyone wants up to date code let me know
WooHoo I finally made it on HaD with one of my own projects! You guys just made my morning!
I’m planning to rebuild this display with a bent acrylic base and many more features. RGB LED backlighting, a webcam for intrusion detection, etc… I might even make a kit with the basic parts so others can build and hack their own display.
If only there was some universal portable device that could connect to various networks and cell services and display pretty much any type of information that exists on the planet in a nice graphical format on demand – now that would be “a more convenient way”. Oh yeah, there is.
On the other hand, nice Pi work.
Good point. Having fun is over-rated.
Great Build! How did you hook up the Raspi to the 5v VFD serial? Resistors?
Nope. Since I’m only transmitting serial data from the Pi to the VFD, you don’t need level conversion. The uC on the VFD will register data on it’s rx pin even at 3.3v. The pi will be fine because it never sees any voltage greater than the 3.3v its sending out.
I’m glad you finally got this up and running! I’ll have to come take a look when I’m back on campus.