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







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.

You are able to input a floorplan for your house/flat/apartment etc., and it comes with the one I used in the Helmhurts post if you’d like to recreate that. The input is in the form of a .png file, which you may create as you wish. The limitations are that

Each pixel should represent 1 centimetre

Black areas represent open space

Coloured areas represent materials

Colour images will be converted into the nearest colours corresponding to a material

Try to keep images below approximately 500×500 pixels for the sake of RAM and CPU usage. If you have a beefy phone go crazy.

You can save the simulation output at any point, even when the simulation is running. The images are of the component of the electric field out of the plane, and are saved to internal/external storage as appropriate and exported to the camera roll. You can also save a GIF animation of your simulation.

All components of the E and H fields are simulated, though in 2D. Empty space is assigned a refractive index of 1, walls are assigned that appropriate for the material.

The frequency is fixed at 2.4 GHz, but the antenna polarisation and type (single or double) can be adjusted.

This is my first time with Android, or indeed Java, so it’s a little rough around the edges, but it runs happily enough without crashing on my phone.

I hope some of you find this interesting, as always this a bit of fun which shouldn’t be taken too seriously.