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Finished a custom driver board for this old flip dot display salvaged from a bus that I reverse engineered! 16
Finished a custom driver board for this old flip dot display salvaged from a bus that I reverse engineered!
Finished a custom driver board for this old flip dot display salvaged from a bus that I reverse engineered! from electronics
Good job. Love the sound of the flipping action.
So to drive flip a dot on a flipdot display, you have to pulse 12v across the coil under the dot for about 1ms. To flip it back, apply voltage with the opposite polarity… In a display like this, the coils are wired up in a [multiplexed matrix, with a clever arrangement of diodes](https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Fcdn.hackaday.io%2Fimages%2F8293951531552344169.png&f=1&nofb=1) to prevent dots from flipping when they’re not supposed to due to current ‘backflowing’ through coils besides the one at the desired row and column position.
In this particular display, circuitry for driving each of the 7 rows low or high is built into the display module. The drivers for each of the 25 columns were originally located on an external board. The custom controller board I designed contains the 25 column drivers, and controls the row drivers on the display PCB, so that each dot can be individually flipped yellow or black. Then it’s just a matter of writing some code for either an Arduino Nano or ESP8266 to get the dots to display whatever you want. ~~I’ll post a link to the EasyEDA schematic of this board soon.~~
[**Link to schematics, board file, and code**](https://oshwlab.com/cselz/gulton-flip-dot-board)
[This series of videos this guy posted about how he built a custom flip dot driver](https://www.youtube.com/watch?v=4K_9W_0g7Q8) was very helpful as I was figuring this out.
​
(Yes, some of the dots ‘stick’ and don’t flip reliably… this display is pretty old, 80s date codes on its ICs, and likely had a hard life of service on a bus. Still mostly works, maybe I’ll try to fix that.)
You impress me.
Very cool!
What a crazy cool mechanical device! Glad you could get it going! That’s awesome
Wow awesome!
That chorus of clackety clicks! 🎬👂🥰
Cool af
Never heard of anyone reverse engineering a bus before but nice project anyway!!
Here in Philly they removed the flip board from the train station and MANY people wish we had it back!
Wonderful!!
Was the display showing “`RVICE`” (as part of an “`OUT OF SERVICE`” sign or something) for most of its lifetime? The lighter dots have a washed-out color as a result. The top row was partially in the shadow of a frame, and other dots whose color does not correspond are likely results of being either misflipped or swapped over the unit’s lifetime. You may think a panel showing constant text is ridiculous but [this panel](https://www.metro.cz/me-hlidac.aspx?idc=6834) in Prague’s most hostile bus station has been like that for years. If it is possible, you might want to place them all into a single rectangle so that they don’t look out of place. Also, the original user might have been a psychopath who used a non-monospaced font, disregarding the 5-column boundaries (or was the panel not divided into letters originally?)
>█▀▀▄─ █───█ ─▀█▀─ ▄▀▀▀▄ ─█▀▀▀
█▄▄▀─ █───█ ──█── █──── ─█▄▄─
█▀▄── ▀▄─▄▀ ──█── █───▄ ─█───
▀──▀─ ──▀── ─▀▀▀─ ─▀▀▀─ ─▀▀▀▀
Awesome. I have a number of those salvage modules as well. Good work!
Where does one source out a salvaged bus flipdot display? I wouldn’t even know where to look!
The dediction to make this work… Briliant! I love it
ok i found out a new hobby that i am going to fail miserably at