## Leon Botha

Software , South Africa## Thermaltronics Shortest Path Circuit

01 Jan 2020 15:20 | Posted by Leon Botha on 01 Jan 2020 |

# Thermaltronics Shortest Path Circuit

This project is inspired by the Shortest-Path-By-LED method used to find the shortest path between two points using a physical electronic circuit representing the path made out of LEDs which would light up if they form part of the shortest path, thus easily showing the shortest path as an answer between two points where electricity is applied.

The goal of thermaltronics is to make use of the thermal properties of electrons instead of LEDs. In our circuit we are more concerned with transferring heat between specific points in the circuit.

## Why Thermaltronics?

At first it may sound counter-intuitive as to why not simply use the electrons directly instead. The reason is that there are specific logical processes which can easily be reproduced by looking at the total energy/wattage in the form of heat instead of only a specific property such as Voltage, Resistance or Amps. Also, it can be pointed out that the total power in a system cannot be manipulated without adding more power or using power, whereas quantities such as resistance, voltage and current can be manipulated with passive components (such as using a step up transformer to adjust the voltage higher) or even inherently by the circuit layout.

## Does it really deserve this much consideration?

Certainly, in my opinion I would say yes! One key thing that computers cannot do in a timely manner is finding the shortest path between a polynomial line such as a set of roads on a map from Point A to Point B. The standard algorithm takes multiple iterations to find the best solution because there are so many possibilities. With a thermal circuit we could instead find the answer instantaneous barring we have a scale model of the path.

# Practical Implementation

To build a thermaltronic circuit you need essentially only need access to conductive ink and a printer.

High quality thermal paper. The paper will need to absorb the heat from the circuit. If the quality of the paper is too low then thermal transfer between points with the same resistance will have different wattage ratings, effecting the results.

The circuit will be powered with a normal power supply.

Measurements can be done in novel ways depending on the context of the circuit’s solution. Standard electronics tools such as ammeter, voltmeter, etc. can be used as well as thermal-specific measuring devices such as a thermal-imager.

## Example 1

### Finding shortest path in a city.

To find the shortest path with the thermal method, we take the following steps:

- Map adjustments.

We need a map of the roads involved. The map needs to be adjusted to cater for dynamic data not actually on the map such as traffic lights and stop streets. One way this can be done is by increasing or decreasing the width of the line representing the street or point of interest. For this example, this step can be the most difficult but luckily only needs to be done once and saved. For our proof of concept, we will assume a simple city road layout. - Print the map to scale with conductive ink.
- Attach the power supply between the source position and destination.
- One way to determine the shortest path direction quickly is to simply increase the power output by the power supply. Essentially, there will be a threshold where the path of least resistance will transfer more power than the thermal paper can handle and simply burn out. Since power is dissipated more toward the end of a circuit, the first component in the circuit relative to electrical negative will be burnt out. This point of burnout is the road we need to follow as the shortest path to our destination. We can once again apply electricity right after the burnout to obtain the next shortest direction and essentially only need to check at follow-up intersections of roads. Eventually we will be led to out destination via the shortest path with no wasted iterations: every check will result in a valid path.

The second method is to instead of burning out the shortest path, we look at the circuit through a thermal image to see which path is the brightest, and simply follow that route.

## Example 2

### Simulating fluid dynamics

Modelling and simulating fluid dynamics on a computer requires a lot of computational power due to the huge number of calculations that need to be performed.

To get past this, a thermal circuit can be built to represent the circuit of the fluid. Since electricity will follow all possible paths, viewing the circuit under a thermal imager will visually represent the pressure at each specific point. Alternatively, the path of least pressure can be determined and, by inverting the proportions of the circuit lines, the path with the highest pressure can be determined.

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## Why I created Robotica.co.za

06 Aug 2019 00:25 | Posted by Leon Botha on 06 Aug 2019 | Last Comment by francois Anker (13 Minutes Ago) |

## Why does Robotica exist?

Robotica was created to help connect South African inventors & IOT developers with prospective clients.

Since I have very little time to take on custom projects, and, my main goal is to grow Leobot Electronics, I would rather facilitate the process of connecting customers with each other than by means of Robotica.

Feel free to post anything you might find interesting or simply wondering about and, if you have projects willing to share publically, there is a dedicated area to do so in order to help clients find you.

This site will be updated periodically and hopefully become as comprehensive as possible to help other IOT developers in South Africa and, inventors & scientists in general.