More on the Mystery CCD

Yesterday I posted about a mystery CCD that I found in a flatbed scanner. It has no part number on it; all I knew was that it has 22-pins. I was hoping that it was like an LCD module---multiple vendors but a single footprint. Sadly, this is not the case.

Proof by counterexample: Toshiba produces at least two 22-DIP CCDs with incompatible footprints: the TCD1707D and the TCD2905D. From my analysis below, I now know that this CCD is neither of those.

I pulled out the continuity tested and started tracing connections. Here's what I've found:

1. GND
2. GND
3. buffered input 1
   
4. GND
5. buffered output 1
   
6. +12V
7. GND
8. buffered input 2
9. buffered input 2 (8 and 9 are the same)
   
10. GND
11. GND
12. GND
13. odd, see below
14. buffered input 3
15. +12V
16. GND
17. buffered output 2
18. buffered output 3
19. GND
20. buffered input 4
21. GND
22. GND

By "buffered input," I mean that the pin is driven by a 74HC04 inverted, through a resistor. By "buffered output," I mean that the pin is fed into a simple transistor inverter. By "odd", I mean that two '04 inverters are put in series and drive themselves through a capacitor. The output also drives this pin through a resistor.

Since this device has three outputs, I infer this is a color CCD. I suppose I could have read the packaging on the scanner, but I threw it out before I thought to check.

The Turing Alarm Clock

This is an old invention of mine. I had trouble waking up for work, and traditional alarm clocks didn't seem to help. I learned to hit the snooze or off buttons in my sleep. The problem was that alarms are too easy to turn off, and so I set forth to create an alarm clock that challenges me to prove that I am awake.

How should it challenge me? Well, I'm from a math background, so the natural choice is with arithmatic. A problem like 23*17 + 6 will keep me thinking for at least 20 seconds; if the alarm clock makes me solve five in a row, then it can be sure I'm awake. There's no way I can learn to do this in my sleep.

The design is powered by a PIC16 microcontroller, which manages the user interface and keeps time. It displays the current time and the arithmetic challenge via a cheap lcd from all electronics.


The design is free and open source; do whatever you want with it.

• The source code.
• The schematic and board layout (in ExpressPCB format), and an image of the layout.

If you wanted to make advancements to the design, may I suggest:

• A battery backup. As it stands, you must have enough will power to leave it plugged in.
• A radio? I suggest the Si4701 single-chip radio.
  

I will be demoing this thing at the next meeting of Make:NYC. Come check it out!