Logic Lab 1G

Roughly a year ago, we featured David Jonson-Davies’ Logic Lab Trainer, which let you to connect PCB logic gates like AND, OR, and NOR together with jumpers, and toggle inputs using four slide switches. Outputs are then shown via a series of five LEDs. The PCB logic gates, however, were actually simulated by an AVR microcontroller.

While an AVR microcontroller is more than up to the job, it needs to be programmed, adding a bit of difficulty to the project. Also, purists might take issue with the fact that it doesn't use actual discrete logic elements. Johnson-Davies designed the new Logic Lab 1G using (actual) 1G logic gates. This means that the device can be duplicated without AVR programming, though the BOM and soldering required are a bit more complicated.

Still, when you’re done with the soldering, it’s ready to use. Plus, there’s no nagging feeling that your simulated AVR logic is somehow improper versus using actual logic elements.

Since implementing the first Logic Lab trainer, Johnson-Davies has come up with five more logic problems for exploration, bringing the total up to 14. These puzzles include building a majority vote machine – where the LED goes green when the majority of inputs vote 1 (yes) or red if most inputs are 0–a binary adder; a binary palindrome checker, and more.

Another interesting feature of this device (as well as the original) is that the inputs and outputs are connected to header pins, enabling them to be connected externally as needed. The new version also allows for the use of toggle switches. This should make quickly flipping input bits much easier than the slide switches that were used in the first implementation.