Building an Analogue Computer to Simulate Neurons

The rapidly-improving speed and versatility of digital computers has mostly driven analogue computers out of use in modern systems, as has the relative difficulty of programming an analogue computer. There is a kind of art, though, in weaving together a series of op-amps to perform mathematical calculations; between this, a historical interest in the machines, and their rarity value, it’s no wonder that new analogue computers are being designed even now, such as [Markus Bindhammer]’s system.
The computer is built around a combined circuit board and patch panel, based on the designs included in three papers in a online library of analogue computer references. The housing around the patch panel took design cues from the Polish AKAT-1 analogue computer, including the two dial voltage indicators and an oscilloscope display, in this case an inexpensive DSO-138. The patch panel uses banana connectors and the jumper wires use stackable connectors, so several wires can be connected to the same socket.
The computer itself has a summing amplifier circuit, a multiplier circuit, an integrator, and square, triangle, and sine wave generators. This simple set of tools is enough to simulate both simple and complex math; for example, [Markus] squared five volts with the multiplier, resulting in 2.5 volts (the multiplier divides the result by ten). A more advanced example is a leaky-integrator model of a neuron, which simulates a differential equation.
We’ve covered a few analogue computers before, as well as a neuron-simulating circuit similar to [Markus]’s demonstration.





was less complex, less resource-hungry and still got all the things done. Maybe it is worth another look, before the AI Crisis forces us all back on Windows XP systems like the one featured in this video.



