Repairing a VFD driver on a car stereo

We love seeing repairs and always marvel at the ability to track down the problem. [Todd] seems to have a knack for this. He was met with a lot of adversity when trying to get the Vacuum Fluorescent Display working on his car stereo. A lot of persistence, and a little bit of taking the easier way out let him accomplish his goal.

The head unit is out of his 1994 Jeep. He knew the radio functionality still worked, but the display was completely dark. After getting it out of the dashboard he connected it to a bench supply and started probing around. He established that the data lines were still working by setting the radio to auto scan mode and testing with a multimeter. When he went to measure the cathode pins he didn’t get any reading. It seems the driver which supplies that signal is burnt out.

One easy fix would be to replace the parts from a scavenged unit. [Todd] hit the junkyard and picked up one from a Jeep that was just one model year apart from his. Alas, they weren’t exactly the same, and although he swapped out a chip (using a neat heated solder sucker) it didn’t work. In the end he simply dropped in a power resistor to use the 12V rail as a 1V at 0.1A source for the filament.

You can see his repair extravaganza in the video after the break. If you’re looking for tips on scavenging these types of displays check out this post.

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An ice tube clock for the TI Launchpad

Because Nixies, Decatrons, and VFD tubes really are that cool, [cubeberg] over on the 43oh forums designed an IV-18 clock for the TI Launchpad.

Like adafruit’s Ice Tube clock, [cubeberg]‘s project uses a surplus Russian IV-18 VFD tube conveniently sourced on eBay. On the board, there are three buttons for changing the time and setting the alarm along with a MAX6921 VFD tube driver and a small switching regulator to boost the 5 Volts on the Launchpad to the 50 V the tube requires.

There was a little bit of space left on [cubeberg]‘s PCB design, and he filled that space with a header for a buzzer and a temperature sensor. Right now, the code doesn’t support an alarm function and he’s still waiting on a few components to finish off the thermometer portion of the board, but it’s still the makings of a very nice clock.

If you’d like to grab your own Launchpad ice tube clock, [bluehash] is organizing a group buy for 430h forum members. If they can get 15 pieces built, the clock will cost less than $5/unit. Very cool, and very cheap when you consider TI is practically giving Launchpads away.

[Todd] literally debugs this printing calculator

This printing calculator is a thrift store find. [Todd Harrison] picked it up for a measly $3, and it still works! But the device is about twenty years old and he thinks it’s time to clean up the aging hardware.

After cracking open the case he digs out some of the stuff that has made its way inside. This includes a few dried up moths (debugging complete). While everything is open he gives a tour of the components. The calculator has a VFD which is definitely worth the price tag of the unit even if you just want to reuse the display in another project. But that’s not all. The printing head would be a fun thing to play with as well. We could see using this in projects similar to some of the thermal printer hacks we’ve seen.

When put back together, and given a new ink ribbon, the unit is ready for another 10-years of holding down one corner of your desk. Don’t miss [Todd's] tear-down and clean-up video after the break.

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Six-digit VFD alarm clock

[Haris Andrianakis] just finished building this very clean-looking vacuum fluorescent display clock. It shows six digits using IV-11 tubes, and also has a half-dozen RGB LEDs to spice things up (check out the video after the break for an example). An ATmega168 drives the device, controlling the display and serving as a battery-backed real-time clock.

As with any tube-based clock there’s a fair amount of work that goes into driving the display. Each tube has a filament which requires 1.2V, and the segments themselves need 60 volts to light up. The microcontroller is not hard to protect; this is done with a series of transistor-based circuits used for switching. But the need for three voltages (to power microcontroller, filament, and segments) means a more complex PSU design. [Haris] chose to use a MAX6921 to simplify the process.

If you’re considering building something like this, we’d recommend looking for some 12-segment tubes. As we’ve seen before, they can display letters as well as numbers in case you wish to repurpose the device in the future.

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Putting Twitter in a VFD clock

Not content with only knowing the time, [trandi] decided his Vacuum Fluorescent Display clock would be much better if it displayed the weather and a Twitter feed.

[trandi] received a Lady Ada Ice Tube clock last month. The kit went together almost too easily. Now he had to, “make it connect to other ‘stuff’ and display some custom messages.” After playing with the firmware to display a Hello World, [trandi] mucked around with the GPS mod and figured out how to add scrolling text over a serial connection.

A serial connection to an Internet-connected computer is all well and good, but [trandi] really wanted a stand-alone solution. A tiny WiFi to RS-232 board was sourced and the work of getting a clock on the internet began in earnest. After a weekend was wasted trying to debug the HTTP mode of the WiFi board, [trandi] gave up and used TCP mode with manually constructed HTTP headers.

The clock gets the current weather and a Twitter feed. To one-up to the Ice Cube GPS mod, the clock now sets its own time from the Internet. Check out the video of [trandi] showing off his Internet clock and fine collection of single malts after the break.

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VFD Hacking

vfd_hacking

[Mostafa] was a bit bored and had a broken DVD player sitting around, so he decided to take it apart to see what made the machine’s LCD panel tick. Once he popped it open, he discovered it wasn’t an LCD panel at all, it was a VFD.

The seven segment display looked to be controlled by an ET16312n VFD driver, so he dug around online and found a datasheet for the chip. After looking at the documentation he was pretty confident he could get things working without too much trouble. He started tracing the board for the STB, CLK, Din, and Dout leads he needed to set up serial communications with the panel and was on his way in no time.

He hooked the panel up to the parallel port on his computer, and got busy hammering out some C code to write text to the display. Right now, the code lets you scroll text across the display, which is about as far as [Mostafa] cares to take it. It was done mostly as a proof of concept exercise, but since this VFD is compliant with the same NEC programming standard that most VFDs use, his code can likely be reused to drive any similar display with very little tweaking.

How a HP VFD Module was Reverse Engineered

We all love getting a good deal on sweet parts, but not all of them are documented. Some of us have trained our eyes and brains to spot “timesinks”, having been burned before. The rest sit down with whatever pile of stuff they have on hand, and figure out how to talk to that HP Media Center VFD.

[Jayeson] found some good deals on some Vacuum Fluorescent Displays from a HP Media Center computer as “new”, from some (unmentioned) shady dealers. Once receiving his B stock displays he needed to figure out a way to make them work.

Fun and excitement includes: figuring out the pins, first attempts of communication, getting the data sheet for a house brand chip… that still has the Atmel stamp on it, sniffing traffic with a logic analyzer, and deciphering that data. All that while being a pretty interesting read, good showing of willpower, and resulting in a couple Arduino Libraries as a bonus.