We’ve seen a few 1-D pong games recently, and they’ve all be controlled using microcontrollers. Inspired by some of these hacks, [mischka] built the monoPong using a handful of logic chips.
The monoPong has four major components. A 555 timer in astable mode provides a clock source which is fed into a 4510 decade counter, which connects to a 4028 BCD to decimal decoder to drive the LEDs. Finally, a 4011 NAND gate IC is used to deal with the button presses. Two of the NAND gates form a RS flip-flop, and the other two NAND each player’s button with the last LED on the player’s side of the strip. If the player hits the button when their LED is on, the RS flip-flop toggles and changes the decade counter from count up to count down mode. This makes the ball bounce back.
[mischka] finished the project off by putting it in a wooden box and drilling holes for the LEDs, buttons, and a power switch. The final product looks pretty good, and is a great example of how you can use a couple logic chips instead of a microcontroller.
After the break, watch a quick game of monoPong.
Continue reading “monoPong: A CMOS 1-D Pong”
If you’re just starting out in your quest to build really cool electronic devices, you’ll find a ton of options ready for the beginner. The Arduino makes toggling pins dead simple, and the Raspi brings the wonders of blinking a LED from the command line down from the gods and into the hands of the common man. These are all software platforms, though, and if you want to learn digital logic with hardware the best option is still a drawer full of 7400-series logic chips.
[Colin O’Flynn] hopes to change this with a beginners board for digital logic hardware design. It’s called the BORA, or Binary explORer boArd, and brings digital logic to a convenient package that is far less frustrating than a breadboard full of logic chips.
The BORA is based around a CPLD – a cousin of the FPGA-powered devices we see from time to time – that allows any student of digital logic to program the device and fill macrocells with NANDs, NORs, and ANDs.
The Xilinx device used in the BORA has about 1600 gates that can be programmed; more than enough to complete all the projects in the online lectures [Colin] has put together. You can check out the documentation for the BORA over on the official site, and the demo video after the break.
Continue reading “Bora board teaches binary hardware”
If you’re going to learn digital logic, why not aim high? That’s what [Easton] and his friend did when they built a clock using only 4000-series logic chips. On a breadboard, no less.
For a 1 Hz clock, [Easton] and his friend used a 4060 counter paired with a flip flop. This counts off 59 seconds until, with the help of an AND gate, the seconds counter rolls over to zero. After repeating that again for the minutes and building a similar circuit for the hour, and [Easton] had a working 4000-series 24-hour clock.
The breadboard clock may not be the prettiest thing, or a textbook example of how to prototype circuits, but that was fixed with [Easton]’s friend’s PCB layout of a 12-hour clock. We couldn’t find any pics of this, but we’re sure it’s awesome and a great way to learn about logic and design.
[Bertho] really enjoyed pawing through the pile of projects submitted to the 7400 logic contest. But one thing kept hitting him with the vast majority of the entries: decoupling capacitors were missing from the circuits. If you’ve worked with microcontrollers or digital logic chips you probably know that you’re supposed to add a small capacitor in between the voltage and ground pins for decoupling purposes. But do you know why? [Bertho] put together a great post that looks that the benefits of using decoupling capacitors in your circuits.
He set up a circuit using a 74HC04 inverter and put it to the test. The image above shows current measurments with the inverter under load. Images on the right show a decoupled circuit and the ones on the left shows a circuit without that capacitor. You can see that the decoupled circuit has much smoother signals when driven high. But it’s not just the smoothness that counts here. [Bertho] goes on to discuss the problem of slow rise-time caused by a dip in current flowing into a chip’s VCC pin. It can take a long time to get above the threshold where a chip would recognize a digital 1. Throwing a capacitor in there adds a little reservoir of current, just waiting to fill in when the power rail dips. This feeds the chip in times of need, keeping those logic transitions nice and snappy.
[Spi Waterwing] wrote in to make sure that we were aware of Logisim, a Java-based open source digital logic simulator. We’ve used Atanua quite a bit in the past but hadn’t heard of this program. It seems to have a pretty big educational following and right off the bat it’s got a feature we’ve always wanted, the ability to build your own ‘black box’ logic devices. That is to say you can build your own circuit out of logic gates and then package it into a part to be plopped into your next design. What it doesn’t have is the series logic chips that we’re used to with Atanua, but you can build your own with the black box feature if you really need that kind of functionality.
So grab a copy and try building that binary calculator project from last month.
What you see above is a master clock. It is the center of a system that can run an unlimited number of slave clocks, keeping them on-time thanks to its ability to synchronize with an atomic clock. [Brett Oliver] put together the project back in 2005 using digital logic chips, and no programmable microcontrollers. This includes everything from the binary decoders that drive the 7-segment displays, to the radio transceiver board that gathers the atomic clock data, to the various dividers that output 1 second, 2 second, 30 second, 1 minute, 1 hour, and 24 hour signal pulses. It’s a well document and fascinating read if you’re interested in digital logic clocks.
Don’t feel like shelling out $5 for a fancy factory made calculator that won’t even do binary math? [Jeff] decided to prove his mastery of gates and his disdain for base 10 by building a binary calculator using XOR, AND, and OR chips. Calculations can be input in two ways: through digital logic headers or by three banks of DIP switches used to enter the operator and the two operands. Although limited to addition and subtraction, this is a great way to make sure you really understand digital logic. Take a look at the rough design schematics in his album. The design is modular so if you have one of each gate and a few LEDs sitting around you can give this a whirl.