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• 7-Segment Display

  Michael Gardi • 5 days ago • 0 comments

  I purchased some MAX7219 based 7-Segment displays and reworked the case "small display" model to hold the display. The digits are larger than on the original and the color is wrong but I think I can live with that. 

  I had an ESP32 on hand and have decided to use it for this project. It's total overkill for the straight calculator version, but will hopefully have the horsepower to allow me to do some cool stuff for the "next generation" build. The display's 3-pin SPI interface leaves a lot of I/O pins available for other stuff.

• Original Trekulator Working Better?

  Michael Gardi • 09/10/2024 at 19:49 • 0 comments

  So I was demonstrating the Trekulator to someone and at first it wasn't working correctly. The unit would power up but the buttons were not working. After a couple of power cycles the keys started working again and the = sign would now play the sound (badly as before) but would update the display with the result of the last operation. Yay. Seems to be holding after multiple reboots so fingers crossed.

  I had another quick look at the speaker. When I first opened up the Trekulator I noticed that there were two short wires soldered to the PCB that had obviously been cut, and I just assumed that they were for the speaker. To verify this I watched the Computer History Archives Project video again and captured the following two screen shots:

  The one on the left is from the unit with the working speaker, and on the right from the one where the speaker had been removed.  Notice the blue and white wires in both images almost certainly verifying where the speaker was attached.  Unfortunately for me this is exactly where I attached my speaker so I now know that wiring is not the reason my unit does not emit the "calculating" tones correctly. This will require further investigation, but then again maybe it will "just start working" down the road. It could happed ;-)

• Original Trekulator Mostly Working

  Michael Gardi • 09/06/2024 at 23:58 • 0 comments

  In order to more easily model the Trekulator case I carefully removed all of the internal components. In the process I noticed a couple of loose wires, so when I reassembled the unit I reattached the wires. At the same time I installed a small speaker since my Trekulator did not come with one.  It looked like the speaker had been intentionally removed since the speaker wires were cleanly cut, and after watching the STAR TREK Inside the RARE TREKULATOR CALCULATOR video I suspect the speaker was removed because the sound effects were pretty annoying IMHO.

  At any rate my Trekulator now powers up. All of the keys and the display seem to be working. The two issues I have found are:

  1. The sound is not correct. Perhaps the speaker I installed is not a good match?
  2. The = button triggers the sound as expected but the display does not update with result of the last operation, it still shows the last number entered.

  Here is a short video of my Trekulator in action.

  If anyone has any thoughts on what might be causing these failures please get in touch.

• Modelling

  Michael Gardi • 09/06/2024 at 14:32 • 0 comments

  So I spent the last couple of days with calipers, rulers, and protractors measuring and modelling the Trekulator case. I really enjoy this kind of work. I find it to be challenging and relaxing at the same time. I helps when the end result turns out pretty good.

  I'm on the lookout for a better color match but the case is pretty much done.

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