Category Archives: 7400 contest

Jonathan entered a Flickering Jack-o’-lantern for the Open 7400 Logic Competition. He recorded a video of his project, which is available below. I used a 74HC14 to create four different square waves of different non-harmonic frequencies that were mixed together to flicker a red and blue LED. Via the contact form.

Embeddederic entered a 7400 series logic PLL-based switch-mode power supply into the Open 7400 Logic Competition. Via the forum.

Jason added another entry to the Open 7400 Logic Competition: 80M direct conversion receiver I had fun using the 74HCU04 to make a little TRF AM radio, but my original goal was to build a direct conversion receiver. I didn’t think I would have time before the deadline, but I managed to squeeze it in with […]

Andrey entered a Game of Life build from CMOS logic into the Open 7400 Logic Competition: This was supposed to be my entry for Open 7400 logic competition. It’s Conway Game of Life on 8×8 LED dot matrix, made with almost only 74HC and 4000/4500 series of CMOS logic chips. Via the contact form.

Shaos entered a (balanced) ternary electronic device based on the 74HC4052 into the Open 7400 Logic Competition. Ternary Balanced ternary is a base-3 number system, instead of bits (0, 1, 10, 11, etc), this counts in trits (-1, 0, 1): The “Test bed” consists of 20 sockets for testing “our standard ternary components“. For ternary […]

Matt built a fully featured Drum machine for the Open 7400 Logic Competition. Check out the video of its operation and his sound generating skills below. This is a four-channel, sixteen-step percussion synthesizer/sequencer created entirely from discrete logic chips (mostly 74HC-series parts). That’s right, no microcontroller or software of any sort. It was created for […]

Joe entered his Horologium Romanum into the Open 7400 Logic Competition. It is a clock that displays it’s time in Roman numerals built from logic ICs. There is a video of it below. Despite the Roman Empire’s  sanitation, medicine, education, wine, public order, irrigation, roads, fresh-water system, and public health: they never had a decent […]

Luc entered his Wheely bin night reminder into the Open 7400 Logic Competition: Because the competition was so open ended in its brief, I placed two constraints on myself: First, I had to make do with the logic chips (and other components) I had on hand. No going to Jaycar or placing an order through […]

After being discouraged by a failed order for their initial entry, Ben and his girlfriend decided to enter a somewhat different design into the Open 7400 Logic Competition. It consists of taking their anger out on 7400 chip. By pumping 1 Amp of current at 12V into the IC, they turned it into a heater, […]

Daniel entered an Electronic realization of Etch-A-Sketch toy into the Open 7400 Logic Competition: This project is an electronic realization of the famous Ohio Arts “Etch-A-Sketch” toy, with a twist.  Like the original, two rotary knobs are used to move a cursor horizontally and vertically, respectively, but unlike the original, a third knob selects one […]

Christopher created a Drum Machine for the Open 7400 Logic Competition. He also documented it in a video below. The idea for building a drum machine came from a discussion I had with my roommates in which we were talking about the popularity of drum machines as simple web applications. I decided to try to […]

Juan entered an Accelerometer controlled racing game into the Open 7400 Logic Competition. Check out the video of the gameplay below. My project is a simple video game in which you control a car and have to move it sideways in order to avoid obstacles. Via the contact form.