Helmhurts Android App

Update (2024)

The Android app below will no longer receive updates, but you can access an improved online version at https://wifi-solver.com

Original post (2014)

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What a fancy icon! You should probably click it.

The recent attention this humble blog received was surprising to say the least. Despite continuing to be slightly bemused by it all, let it not be said I don’t listen to the comments I receive.There is therefore an Android app here:

Get it on Google Play

which is a version of the 2D FDTD simulation, and will run happily on a modern phone. My Nexus 4 manages about 1 step per second for an array size 350×600, and more up-to-date phones will surely be much quicker. There is a review here in Spanish.

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Helmhurts

A few posts back I was concerned with optimising the WiFi reception in my flat, and I chose a simple method for calculating the distribution of electromagnetic intensity. I casually mentioned that I really should be doing things more rigorously by solving the Helmholtz equation, but then didn’t. Well, spurred on by a shocking amount of spare time, I’ve given it a go here.

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Damp and Driven Swingers

We’ll continue the theme of this fledgling blog along the lines of fractals, pretty pictures, spirals and Matlab. All of this neatly encapsulated in the concept of the damped and driven oscillator, alluded to somewhat scandalously in the title. In particular, for simplest conceptualisation (and maximum innuendo potential) we’ll look at the humble pendulum.

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Ant-ics

I was told an example interview question involving ants following one another around in a square, and it continued to bug me for a while (pun wholeheartedly intended). The specific wording of the problem is this:

4 ants are place at the corners of a square of unit area, and each ant walks towards the ant ahead of it. What is the shape of the path the ants take, and how far do they walk until they meet?

Sounds fun and relatively simple (though not so much in an interview situation!), lets have a look.

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WiFi strife

WiFi Solver app

To simulate your own WiFi signal, check out:

https://wifi-solver.com

WiFi Strife

I’ve recently moved into a new flat, and to celebrate I bought a WiFi card for my PC rather than relying on a power line LAN adaptor – plug sockets are a valuable resource in a Victorian flat conversion and so shouldn’t be wasted on such trivial things.

Unfortunately, with my lovely new card freshly installed my connection was erratic at best, disconnecting more or less at random and generally being a first-class first-world problem. In a fit of internet-deprived mania I decided to investigate, the first act being to crash out a quick CAD drawing of the flat layout in Sketchup:

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