A black circuit board with many colored banana connector plugs in placed on a table. Behind it, two analogue voltage dials stand on either side of an oscilloscope stand. The oscilloscope is a cheap model, with a small LCD display and an exposed red circuit board.

Building An Analogue Computer To Simulate Neurons

March 8, 2026 by Aaron Beckendorf 2 Comments

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.

DIY Solution Does PoE On The Cheap

December 24, 2011 by Mike Nathan 23 Comments

diy-poe

Depending on the scope of your requirements, Power over Ethernet (PoE) components can get pretty pricey. [Fire] wrote in to share a 4-port PoE solution he put together for under 20 euros (Ignore any SSL errors – we’ve checked it out, it’s safe).

The most expensive part of the build was the 8-port patch panel he purchased for 11 euros. He popped it open, wiring the first four ports for power after drilling spots for an indicator LED and the PSU. He wound the power lines through ferrite beads to hoping to dampen any interference that might occur before reassembling the panel.

In the picture above, you might notice that the panel is being powered via the first Ethernet port rather than through the barrel jack, which [Fire] said was done for testing purposes. When deployed in his network, he plans on using a regulated power supply from a junked laptop to provide electricity.

If you need to provide PoE to devices on your network, this is a great way to go about it. Using a patch panel like [Fire] has gives you the flexibility to easily wire up as many powered ports as you need without much hassle.