74xx Update

This post is just an update of what I've been doing with the 4000 series rocket launcher. I also thought that in the spirit of OSHW, I should try to upload as many files as I could. So first off, here is the PCB layout, ready for toner transfer. Here is the corresponding Fritzing file (Note: I really prefer Fritzing to Eagle, but I only use the PCB section, not the breadboard or schematic). As for the second part of the launcher, the actual seven-segment countdown, here is the PCB PDF and the Fritzing file in case you want to change anything. I recently found out about a new kind of etching process (which involves a sponge and much less time) so etching pictures should be up soon. If you've been looking at Dangerous Prototypes recently, there are some incredible circuits made of these chips, but I'm hoping this will get a "Not Over the Top" award or something. Check in soon for etching instructions!

EDIT:
Unfortunately, just a few hours before the deadline for the competition, my last part of the circuit failed. I attempted to solder the last 4017 directly to the PCB without a socket, but it burned out or something because the the circuit failed to work. Too bad. Hopefully they have another competition!

Also, I have been very pressed for time recently. I should have a lot more time now, so hopefully some post will come out.

74xx Competition! Part 1

As some of you may know, Dangerous Prototypes is putting on this big competition out for circuits that use discrete logic chips like 7400's or 4000's. In case you haven't seen the prize list, I suggest you cruise on over the dangerousprototypes.com and check it out.

         A while ago (in sixth grade) I built a rocket launch controller exclusively out of 4000 series chips and  555 timer. It was all on a breadboard and pretty messy. Now, in ninth grade, I've decided to get it back together, but this time on a PCB. But wait, there's more! I'm etching it myself, so it has to one-sided. Yes, there will be some jumpers, and the 555 will be replaced by an ATTiny for controllability and simplicity, but the displays and such will all be discrete. The first part I'm etching is the ATTiny and 4017 circuit. It will drive a bargraph display. Later, the divide-by-ten output of the 4017 will drive a 4026 [EDIT: 4029] (BCD count-up/count-down), which will drive a 4511(BCD to seven-segment display driver), and another 4017, the tenth output of which will trigger a relay and thus the rocket. In case that doesn't make sense, here's a super-simple diagram:

Sorry for the poorly drawn lines...