7400 competition entry: 80M direct conversion receiver

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 […]

7400 competition entry: Game of Life with CMOS logic

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.

7400 competition entry: Homemade 7400

Arup entered his Homemade 7400 into the Open 7400 Logic Competition. A video of it proving his concept is available below. At an earlier post I’ve said that I didn’t have 7400ICs in my drawer. Surprisingly, the local store was saying 74HC00 out of stock. Hence I decided to make my own 7400 IC. 7400 […]

7400 competition entry: Ternary base-3 electronics using 74HC4052

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 […]

7400 competition entry: C-IR capture device

Kevin entered a Detailed consumer IR capture with 74HCxx series chips for the Open 7400 Logic Competition: This is a CIR (Consumer IR / Remote Control) capture device built with 74HCxx series logic chips. It allows a computer to do a detailed capture with carrier frequency, on/off durations, and on duration pulse counts. Via the […]

7400 competition entry: 8-Channel, 6 -MSPS USB logic analyzer

Helmy entered an 8-Channel 6MS/s USB logic analyzer into the Open 7400 Logic Competition. His device converts the 8 channel parallel inputs into a UART based serial signal. It outputs this serial signal to the input pin of a PL2303 USB-to-Serial chip which sends the data to the computer. Via the forum.

7400 competition entry: Discrete Logic Drum machine

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 […]

7400 competition entry: Horologium Romanum

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 […]

7400 competition entry: Wheely bin night reminder

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 […]

7400 competition entry: Etch-a-Sketch toy

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 […]

7400 competition entry: Accelerometer controlled racing game

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.

7400 competition entry: CD4007-based voice changer

Reymond entered a CD4007-Based Voice Changer into the Open 7400 Logic Competition: The project uses 2 – CD4007 configured as a Gilbert Cell Double Balanced Modulator and an additional 2 – CD4007 for use as a difference amplifier. This kind of effect is known as a Ring Modulator in the audio community… Via the contact […]

7400 competition entry: Capacitance meter

Alvaro built a Capacitance meter out of logic chips for the Open 7400 Logic Competition. His project measures capacitance of a capacitor and displays it on a 7-segment display. It works by using the said capacitor in a RC oscillator, which changes its output frequency proportionally to the capacitance in it’s RC circuit. The frequency […]

Free PCB coupon via Facebook to 2 random commenters

Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times a every week: Free PCB Sunday. The classic. Every week, […]

7400 competition entry: Peltier temperature controller

Michael entered a TEC temperature controller into the Open 7400 Logic Competition. Logic chips control the temperature of a thermoelectric Peltier element (TEC) heating/cooling plate. Current temperature is measured via a sensor placed directly on the Peltier. The target temperature is set by an 8bit dip-switch. The circuit will cool or heat the Peltier until […]

7400 competition entry: LED clock

Michael built an LED clock for the Open 7400 Logic Competition. He added 60 LEDs to an analog clock which are controlled by discrete logic chips. This project uses a standard analog quartz clock and adds 60 LEDs clockwise around it to display the seconds. There are 2 selectable modes via 2 jumpers: Mode 1: […]

7400 competition entry: AM radio transmitter

Andrew entered an AM radio transmitter into the Open 7400 Logic Competition: My 7400 contest entry is an AM Radio Transmitter, which nicely complements another entry. The TX frequency is digitally tunable from 520kHz – 1.6MHz, although this part of the circuit is open loop, so tuning to a specific frequency may require a slight […]

7400 competition entry: Beeping down counter

Chris decided to enter another project into the Open 7400 Logic Competition. The beeping down counter, as it’s name suggests, is a pre-settable timer which beeps and uses a display to show the seconds left on the timer. The goal of this project is to duplicate the down counting circuit used by the character Ivan […]