Author Archives: DP

Miguel sent in his entry to the open 7400 competition. It’s a CMOS frequency counter based around the CMOS 4000 series logic chips. It’s capable of counting for 1 Hz up to 1 MHz. The project consists of a frequency counter that uses only old-school CMOS chips: 4511 display drivers, 4029 decade counters a 4521 […]

Check out Alex’s useless machine with a chain switch. It’s operated with 4 servos and uses 11 7400 logic chops. It’s his entry to the Open 7400 Logic Competition: This is a last minute (and very useless) entry. I wanted to make something that shut itself off, but I wanted it to be different than […]

Oakkar7 shows you how to make an awesome DIY musical keyboard using only 7400 logic. The idea is to design and construct an electronic musical keyboard with some functions, effects etc,. This is my old school project and I remake and modified it. It is fun. Build something that uses or abuses a logic chip and get amazing boards, tools, […]

This open 7400 competition entry is a clock which displays it’s time as text on 32 5×7 dot matrix displays. The display itself is driven via a board that was scavenged from an East-German numerical control unit. I build this clock with an old display-board from an east-german numeric control. It has a one-line display […]

Here’s a bug shaped robot entered into the open 7400 competition. Power by a solar panel, this 7400 logic based robot moves toward the life giving light source. Powered by a solar panel, this miniature robot shuffles towards the light.  This project was a venture into BEAM robotics, a now seemingly defunct genre characterized by […]

Need a quiz show buzzer system? Check this out! A Quiz Show Buzzer was just built only with 74XX series device. A single 74LS373 Octal D-Type Flip Flop was used instead of several AND gates. Eight DATA INPUTs serve as quizzer’s user interface and the eight DATA OUTPUTs were connected to 8-input AND gate which […]

Do you like to play games? Try this Jayahari’s fun Tic Tac Toe game: First of all thanks to DangerousPrototypes! its because of you guys I worked on logic gates after college – else its usually the usual microelectronic stuff! :) This build is a simple ‘Tic Tac Toe’ game. I ended up using 30 Logic […]

Here’s another Open 7400 competition entry a 4-bit homebrew CPU designed by Jaromir: Since I was born in mid eighties, I’ve never experienced real 74xx build. Few gates here and there was common, but lager designs were practicaly uneeded – as microcontrollers, CPLDs or FPGAs replaced need for such as work. But my posession in […]

Check out Giuseppe’s Open 7400 competition entry. It’s a 1 bit microprocessor based on the MC14500 CMOS chip. This circuit is based on the CMOS chip MC14500. This chip is an ICU (industrial control unit) built from Motorola few years ago, it is a 1 bit processor that can do some logical operations. This chip is […]