A further detail on Schmitt triggers: Reading in the Wikipedia article that “a Schmitt trigger can be converted into a latch and a latch can be converted into a Schmitt trigger” made me realize that the ARC Threshold Logic Neuron could be used as a Schmitt trigger. The ‘single-bit’ configuration allows for the threshold and memory properties to be incorporated in one element, as in some of the analogue circuits, rather than separating them into distinct elements as with a flip-flop or sample and hold.

I put together a little example in Audulus.

…what a Schmitt trigger does is it takes a kind of wavy analog signal and turns it into a sharp digital signal
—@TomWhitwell On The History Of Synthesizers

Since piecing together a Schmitt Trigger in Audulus yesterday it’s been interesting to read a little about the various ways in which the basic idea can be implemented. Upper and lower threshold triggers combined with a sample and hold seemed to be the simplest way to go with Audulus, but the Wikipedia article also covers the many ways in which it might be implemented with analogue components.

As with the ARC Threshold Logic Neuron it’s interesting to look at the history of its development and origins in the study of biological processes. Tom Whitwell, in his talk On The History Of Synthesizers, assigns this humble device a central role in the development of not just electronic music, but electronics in general.

I came across Analogue Research’s Artificial Neural Network Eurorack module last year, and have been wanting to re-create some of the submodules in Audulus ever since. The Audulus Library already includes modules for the standard logic gates, but there was something in the addition of thresholds to the Boolean on or off that intrigued me: ARC provides a nice explanation, in both their video and manual, of the biological model on which the Threshold Logic Neuron is based.

As DivKid covers in the final section of his video on the Joranalogue Compare 2 dual window comparator, there’s a lot of fun to be had in the combination of knobs and logic. Mylar Melodies too has some thoughts on Why Logic Modules are Ace!

Robert Syrett orginally posted the DivKid video on the Audulus forum in connection with the uWindow module he based on the Compare 2, and, since it’s a little different to the comparator, I thought it also would be worthwhile to go through the steps of putting together a Schmitt Trigger.

I’ve posted my versions of the ANN submodules on the Audulus forum along with some demos.