Nottingham Hackspace “days accident free” counter

Fowkc tweeted a picture of his somewhat late open 7400 competition entry. It’s a giant 3 digit 7 segment display used to count the number of day’s there hasn’t been an accident in his local hackerspace. You can read about it’s development on his blog. Back in September 2011, Dangerous Prototypes started a competition for […]

Open 7400 first prize winner receives his Analog Discovery bench tool

Matseng shows off the prize he got for taking first place in this years open 7400 contest with his “Constant load with nixie readouts” entry. He chose to get one of the Analog Discovery bench tools Diligent was kind enough to sponsor the contest with. Analog Discovery is a 100 MSPS twin channel oscilloscope, 2 […]

Open 7400 Logic Competition winners 2012

Thank you participating in the Open 7400 Competition. All the entries were amazing! Check out the full list here. This year we tapped community members to judge, and gave great weight to the readers’ choice. The projects with the most votes were awarded prizes. Winners will receive prize information by email in the next 48 […]

7400 competition: Entries and reader’s choice

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 commentators will receive free PCB codes as a thank you for voting. Check out the list below. TV Auto-off […]

7400 competition entry: Lighting effects generator

  Dmitriy entered his lighting effects generator into the Open 7400 Competition. The basis of the device is a multi-bit digital sequence generator that is implemented on a serial shift register [1]. The repetition period of the sequence is determined by the number of bit of a register and much higher than the repetition period […]

7400 competition entry: Build your own FPGA

Nick’s Open 7400 competition entry is an FPGA that is implemented in 7400 series discrete logic ICs: Building a microcontroller or CPU out of discrete logic is a popular hobbyist pursuit, and it serves a useful purpose. Building a CPU from scratch teaches you a lot about CPU architecture and tradeoffs; it’s an interesting and […]

7400 competition entry: I2S DAC with a Class D amplifier output

This I2S DAC with a Class D amplifier output has been entered into the open 7400 competition. It uses a mix of 74HCxx and 4000 CMOS series logic ICs to achieve the desired result. My last minute entry to the 7400 series logic competition. I’m using a SN74HC132 hex NAND gate, a CD4094BE 8 bit […]

7400 competition entry: Signal strobe

Check out Matthew’s 7400 contest entry, a 74xx based signal strobe for emergencies, as well as search and rescue situations. This a signaling strobe, an enhanced one with a siren. My device is built off of 7400 NAND Quad Gate, 2x 7476 J/K Flip Flop, 7432 OR Quad Gate and 4x 555 Timers. Now of course, […]

7400 competition entry: Constant load with nixie readouts

Want to test your power supplies? How about using a constant load with a Nixie display, built entirely out of 4000 series CMOS logic chips. This is a Constant Load generator that is controlled by a keypad. When I started this project I was not sure what it would end up being so I built […]

7400 competition entry: Periodic egg turner for incubator

Do you need an incubator for hatching eggs?  T0mpr1c3 shows you how to easily make a homemade egg incubator: This is a project from a couple years ago, which I published on the members’ pages at the Backyard Chickens forum: An automatic egg incubator with PID temperature control and periodic egg-roller, built into a microwave […]

7400 competition entry: The polonaise machine

Check out Jussi’s 7400 contest entry, the polonaise machine. It’s a sound generator with the Telemann’s Polonaise tune incorporated into the design. After about half an hour of brainstorming I came up with the idea of a modern musical box. In a few moments I had the core of the machine ready on a paper […]

7400 competition entry: Class D amplifier using digital logic

Class D amplifier using digital logic is the open 7400 competition entry by hasn0life: The entry is a class D amplifier made entirely out of discrete digital logic components. I took great pains not to use op amps or transistors or any active devices besides logic gates. Though the amplifier outputs square waves, the process […]

7400 competition entry: A nixie-based Press Your Luck game

It’s time to Press Your Luck! Check out Christopher’s nixie-based Press Your Luck game for the Open 7400 Logic Competition : Press Your Luck (tv game show) in Nixie form, getting a W (view the tube upsidedown) is like getting a Whammy. See how many points (other cathodes) you can get before hitting 3 whammies. […]

7400 competition entry: Frequency counter

Here’s a 6 digit frequency counter by Yi, entered into the Open 7400 Competition. During the Winter break my dentist convinced me that I needed to have my 2nd wisdom teeth removed. Having done this previously without much pain, I thought it would be a good idea. It turned out to be much more involved […]

7400 competition entry: 40xx logic chips project

Nakul Rao I, Nischal Rao, Nikilesh, and Sandesh VS entered a bicycle exercise meter and burger alarm into the Open 7400 Competition. Their project keeps track of your bicycle’s speed, cadence, and distance while you’re exercising. It also acts as a burglar alarm when you’re away. This is something we had done about an year […]

7400 competition entry: CMOS car alarm

Don’t wanna lose your car? Build a CMOS 4000 series car alarm and enter it in the open 7400 competition. Built way back in the 1980s this CMOS Car Alarm provided an entry & exit alarm for my wonderful little Mini. It was built from CMOS series logic to reduce the current consumption and the circuit […]

7400 competition entry: Using two CD4007 IC as an op amp to generate sine waves

Here’s an interesting way of designing analog devices using digital chips. This sine wave generator s based around mosfets contained in the CD4007 IC (a dual complementary pair of mosfets and an inverter). The CD4007 dual complementary pair and inverter is primarily intended for digital logic circuits. It contains an inverter, and two pair of PMOS and […]