Here’s a (hopefully) complete list of entries in the Open 7400 Competition. Please share your favorites in the comments below, your favorites will receive a special reader’s choice prize. Voting ends in 24 hours.
A few commenters will receive free PCB codes as a thank you for voting.
Check out the list below.
- Nixie tube clock
- Moving dot running light
- Propeddle software defined 6502 computer
- 2 bits divider/multiplier
- Telephone Intercom from TTL
- Pen holder
- Water level indicator
- 74LS00 based full wave rectifier
- Lazarus-64
- PCPU, homebrew minicomputer
- Capacitive Sensing, the Hard Way
- Sychnometro Hz
- Pure TTL clock
- New earth time (NET) digital clock
- Discrete servo driver
- Discrete logic POV clock
- Money counter
- Masochist’s video card
- Animated LED Christmas sign
- Analog comparator
- SPI LCD backpack
- Hex KeyPad
- TTL Tilt Sensor
- Lights out game
- TV pattern generator
- Four digit RPN calculator
- CMOS digital clock
- 7400-based USB prank
- The Computer
- Illogical Dickson Doubler
- 7400 Logic E-reader
- Charge pump voltage inverter
- 74Clock
- Safer alarm
- Police lights and siren for a toy car
- Discrete logic preamp
- AM radio
- TimeBonder 275
- TTL based range finder
- Digital die (74XX Family)
- Discrete logic amplifier
- FM modulation and demodulation system
- Beeping down counter
- AM radio transmitter
- LED clock
- Peltier temperature controller
- Capacitance meter
- CD4007-based voice changer
- Accelerometer controlled racing game
- Drum machine
- Etch-a-Sketch toy
- Game of Life with CMOS logic
- Heat generator
- Wheely bin night reminder
- Horologium Romanum
- 8-Channel, 6 -MSPS USB logic analyzer
- Discrete Logic Drum machine
- C-IR capture device
- Flickering Jack-o’-lantern
- Homemade 7400
- Ternary base-3 electronics using 74HC4052
- 80M direct conversion receiver
- Logic PLL based switch-mode power supply
- Silly bunch of unbounced switches
- Bad driver feedback 40×16 LED display
- Nixie tube PLL synthesizer for retro style radio
- RTC with gate IC
IMO,a few of the better entries in descending order of awesomeness are,
Capacitive Sensing, the Hard Way
Discrete logic POV clock
8-Channel, 6 -MSPS USB logic analyzer
Do I get a free PCB,or is it random?
This is the first time I’m the first commenter,so I really hope that counts :P
Capacitive Sensing, The Hard Way – very impressive project with versatile design decisions.
I liked most the “Analog comparator” project as it was one of the most unusual ones. Many others are interesting but nowadays there are too many people who can synthesize logic from 7400 components. I think the competition must show some uncommon ideas rather than complex projects.
The Capacitive Sensing, the Hard Way, really is “the hard way” so I have to appreciate the amount of work that went into building that but I also like the 7400 Logic E-reader.
Capacitance meter is a very nice application for 7400s
Thanks Hélio :) It was actually a bit stressing to build the thing, I was surprised it worked so well in a breadboard [actually I was surprised, due to all the variables involved, that it worked]. Glad you enjoyed it!.
Pity I had not much time to work on it. Last IC arrived 3 days before the contest deadline, and it was a pretty much irreplaceable component – I had to delay all testing, and just sit and wait.
Alvie
my vote goes to “Capacitive Sensing, the Hard Way”
When I was younger I had always wanted to build a TTL clock. So the “CMOS digital clock” is my emotional favourite.
The other interesting project for me is “Capacitive Sensing, the Hard Way”
I’m going to go for the full wave rectifier, just because that was the least expected for me. It doesn’t actually use the intended function of the chip, which I thought was pretty clever.
My favorite is this one: Capacitive Sensing, the Hard Way
The high-frequency mixed signal is awesome, but generating RS232 output with nothing but 7400-shift registers just blows my mind.
A close second is Lights out game which sports an impressive amount of computation in its 42(!!) logic chips.
The best part: those were made by the same person.. Bertho is amazing..
RS232 from scratch is not that complicated, when you are *sending*.
It does get much more complicated when you want to receive. Often we use a 16x sampling rate, with digital filters.
:)
Also gotta go with “Capacitive Sensing, the Hard Way”
My vote to the pen holder! I guess if there is some kind of prize for such an original entry ;)
The best IMHO is Capacitive sensing the hard way, followed by the E-reader, followed by the 8ch Logic analyzer.
My favorite is the Police Lights and Siren for Toy Car. I am impressed by how fully featured the device is using just two logic chips, and it’s a very creative and practical example of how 7400 devices can be used to solve common, mundane problems.
Capacitive Sensing, the Hard Way is by the best imo. A second would be the lights out or also the e-reader is pretty cool.
Capacitance meter works great.
I vote for lazarus! incredible work!
My vote goes to Bertho’s Capacitive Sensing, the Hard Way due to the high quality documentation and very well thought-out design.
i like the “capasaitive sensing” and the “Masochist’s video card” proyects.
Capacitive Sensing, the Hard Way is very well documented and a cool project.
I vote for “Capacitive Sensing, the Hard Way” and “Masochist’s video card”
My money is on Masochist’s video card, but honestly I appreciate everyone’s entry!
Capacitive sensing was awesome and I really liked the combination of 555 and 7400 found in the money counter.
I vote for “Ternary base-3 electronics…”, because I strongly feel that ternary logic is a future of electronics.
May I know why my entry [ENTRY] 40×16 Led Display is not in the list of 7400 compition. Is it invalid entry or you just skiped it.
I’m sorry, this posts was based on the 7400 category of the blog and some posts were miscategorized. Every email and post was recorded to a separate judging spreadsheet, your was included in the judging. I updated the post with your entry too.
“Capacitive Sensing, the Hard Way” gets my vote.
“Discrete Logic Drum machine” is getting my vote.
Gotta say “Lights out game”.
I vote for “Police lights and siren for a toy car”
It may not be the most technical submissions, but I loved the end result product.
I love the E-Reader Project. O-Scope XY projects always amaze me…. I should build one up one of these days.
Can’t get more retro than the ‘Etch-a-Sketch Toy’!
“Capacitive Sensing, the Hard Way” is brilliant. A close second is the lights out game due to the sheer complexity.
“Capacitive Sensing, the Hard Way” is pretty awesome!
I have to say that I really like the Discrete Logic Drum Machine.
I’d vote for my own project, but I’m pretty sure my mom will vote for mine. So, there are a *lot* of really great projects. In my opinion, one of the best is the “Lights Out” game–it is documented well, a finished project, … and its a game!
“Discrete Logic Drum machine” gets my vote
My first vote goes to “Capacitive Sensing, the Hard Way”
Also good ones are the “Logic PLL based switch-mode power supply” , “Masochist’s video card” and the smallest clone of a 7400 “Homemade 7400”
I am competing for this :P
Anyway, there are two projects here (yes, only two) that made me shake my legs, due to complexity, ingenious, documentation, and being almost “pure” 74x/40x series.
One is the “Capacitive Sensing, the Hard Way”.
The other one is “Etch-a-Sketch”.
The first one shares many details with my own design. Although it’s simpler (that’s a good thing), but also does not have to deal with the frequency sweep my design does (clock varies from something about 4MHz to a mere 1Hz).
My congratulations to all contestants. Some very good designs were submitted, and I expect a good one will be chosen [of course I expect mine to win! :)].
It was a pleasure to design and implement the Capacitance Meter for this contest. It was the first thing that came to my mind when the announcement came out, and, since no one helped me choose another one, I decided to do it and submit it. Most parts had to be bought abroad (IC prices in Portugal are absurd).
What made me smile was to see that actually, despite all the analogdigital problems, the design actually worked. I was euphoric :)
Best,
Alvie
??? i DON’T see me entry …. WHY ?
http://dangerousprototypes.com/forum/viewtopic.php?f=62&t=2967
???
thanks Ian to fixing the entry blog …
now i can see my bunch of unbounced switches :-)
I submitted an entry, but I really like the Etch-a-sketch!
I have a couple entries in the contest but I vote for the _Lights Out Game_ because I think it deserves it more. There are too many great entries to chose from!
Christopher Woodall’s Drum Machine gets my vote, for sure!
There are several very excellent 7400 circuit designs in the list, but my favorite by far is the
“Drum machine.”
Oops, I didn’t realize that there were two Drum machines on the list.
I actually intended to vote for Matt’s
“Discrete Logic Drum machine.”
The reason I am so impressed by Matt’s work is that there are many VCO chips out there, but he managed to design 74HC-based oscillators. Kudos!
(no offense to Christopher Woodall)
I personally like the Discrete “Logic Drum Machine”
Dear private web diary,
I hope the winners are announced before the 1st. That way, when I lose, I can egg the judges’ houses on Halloween without raising suspicion. The perfect crime!
My vote is for the Homemade 7400. Excellent way to get around not having the parts you need!
Lights out is just so fun to play around with, also the game has a really nice finish! :)
“Masochist’s video card” is very impressive.
I really liked the Lights Out game.
They`re all really good! but most of them are the sorts of thing that I expected to be presented, I Seriously never figured on someone Having to make their own 7400.
So my vote goes to the Homemade 7400 cct, I just love that sort of philosophy.