Picture of Minidot 2 - The holoclock
title pic.JPG
Well maybe holoclock is a little bit inaccurate....it does use holographic dispersion film on the front to give a bit of depth.

Basicaly this instructable is an update to my previous Minidot located here:
and re-using a lot of code and circuitry from my Microdot located here:

EagleCAD files and Sourceboost code is included in the zip files attached.

Why? The previous Minidot was overly complex, from the Microdot I learned how to do an RTC on a PIC using only a 32.768 crystal and didn't need to use a special RTC chip. Also I wanted to get rid of the display chips from the previous Minidot. So now there is only a power regulator chip and a PIC16F88....just two chips.
The other reasons for an update were my Minidot was getting a bit un-reliable because of the seperate switch board and I wanted a soft fade between dot patterns as well as some sort of ambient light sensor to dim the display at night. The other Minidot was fixed brightness, and illuminated a room at night.

The device was constructed with the aid of the EagleCad software package and Sourceboost compiler. You'll need to have some experience with electronics and programming PIC controllers to start this project. Please note this isn't an instructable on either electronics or PIC programming, so please keep questions relevant to the Miniclock design. Refer to the instructables above or many other instructables on this site for advice on using EagleCad or programming PICs.

So here it is.....Minidot 2, The Holoclock......or Minidot The Next Generation.............

You Rock.
Berkin6 years ago
Sweet! Does this really tell time?
rgbphil (author)  Berkin6 years ago
It does indeed.
dmcole6 years ago
Phil: A couple of the illustration links are producing errors rather than pictures ... Thanks for the work. \dmc
bugQ7 years ago
Would Charlieplexing be possible (and if so, advisable) for displays that use LED devices with more anodes than cathodes, e.g. RGB? It seems that it might become more trouble than it's worth, since it would only save 1/4 of the pins.
rgbphil (author)  bugQ7 years ago
I think so, but as you've noted, you can't save as many pins. For example the original charlieplexing scheme came from a guy in Maxim who wanted to save pins when controlling multiple seven segment displays. I'd suggest popping over to maxim and looking at their application notes on charlieplexing....they're focussed towards seven segment displays, the RGB diodes would be the same, just effectively three segment displays.
McLaren7 years ago
Bravo Phil... A very clever and creative project. Nicely done. I'm impressed. Mike
lamedust7 years ago
This is exactly what I need for my sensory augmentation project. A charlieplexed PWM LED matrix, a mouthful of jargon for this electronics beginner, but I'm determined to figure this out! I love this thing! -bg
rgbphil (author)  lamedust7 years ago
thanks.....would be keen to see what you mean by your sensory augmentation project!
IR camera -> computer output to a charlieplexed PWM vibrating motor matrix
Will be an update to:

Changes would be that I'll be doing some computer edge detection, face detection and have those vibrate more powerfully. This will augment the sense. Also, for me, it'll enable me to see in the dark. Blind people could look at you in the face when they talk to you and still be able to talk. I think that even though the back has a low resolution, I found that a 1/2 separation between points is enough to differentiate.

I need to know if I'm going for vibrating motors (easier) or to actually electrostimulate the back. Which might give me a better resolution, but I don't know how to work with currents that strong, any tips?

ian8 years ago
Its great to see another version of the mini-dot clock! The 32.768hkz crystal for a cheap RTC implementation is really slick. I've been working with the MSP430 lately. Not only does it have an oscillator circuit for the crystal, it has adjustable load caps that can be set from .1pf to 12.5pf in firmware. This is my favorite type of instructable. I would add it to the uC, but it looks like you already have. Keep up the great work.