7400 competition entry – Page 3 – Dangerous Prototypes

7400 competition entry: Animated LED Christmas sign

Raj entered his Animated LED Christmas sign into the Open 7400 Logic Competition. Having already build a PIC controlled version, he wanted to try and control the sign using discrete logic only. The individual letters are build from red LEDs and run of a 32V power supply. Check out the video of this project below. Via […]

7400 competition entry: Masochist’s video card

Chris entered his Masochist’s video card into the Open 7400 Logic Competition. Using only discrete logic his circuit cycles through 8 presettable colors at a variable frequency. Using a simple resistor network he outputs it over the VGA output. It is well documented and all the design files are available. Check out the video below. Via […]

7400 competition entry: Money counter

Here’s an entry in the Open 7400 Logic competition: Money counter It’s a money counter based on pure 7400 logic and a bunch of 555. It can count 5 different types of coins. And it will show the current amount in the 7 segment displays. There are 3 files, two IEE papers (one for spanish […]

7400 competition entry: Discrete logic POV clock

Matt’s entry in the Open 7400 Logic competition: Discrete logic POV clock. This persistence-of-vision clock was built entirely out of discrete logic chips. The design consists of three boards, a LED array and a drive motor. The digit board keeps the time while the display board controls the LEDs. The digit board Every second, a pulse increments the […]

7400 competition entry: Discrete servo driver

Here’s an entry in the Open 7400 Logic competition: Discrete servo driver. This entry is designed to control RC hobby servos. 8bit parallel BCD code input from a dip switch sets a pulse width between 0-25.6ms (180 degrees of motion). However on most servos the first 50 and the last 10 positions are unavailable so you have […]

7400 competition entry: Pure TTL clock

Here’s an entry in the Open 7400 Logic competition: Pure TTL clock A 24 hour clock built entirely out of TTL gates. The time base is a 32.768kHz quartz crystal.

7400 competition entry: Sychnometro Hz

Here’s an entry in the Open 7400 Logic competition: Sychnometro Hz by DolceVii

7400 competition entry: Capacitive Sensing, the Hard Way

Here’s an entry in the Open 7400 Logic competition: Capacitive Sensing, the Hard Way – 16 Channel Capacitive Sensor, RS232 Out

7400 competition entry: Lazarus-64

Here’s an entry in the Open 7400 Logic competition: Lazarus-64 I like the idea of a 74x logic competition! Here is my entry, a retro computer that generates all video using ONLY 74hc logic parts… The latest version even has a 4 voice sound system, including a white noise channel made using a linear shift […]

7400 competition entry: 74LS00 based full wave rectifier

Noels entry for the Open 7400 Logic competition is a 74LS00 based full wave rectifier. I want to have an entry that it simple enough that other people can try out with their breadboards. Something that is easy to do, and yet feature a mis(use) of a typical 74LS00 IC.