WiFi Solver FDTD

WiFi Solver FDTD


With this app you can take a floorplan of your house, set the location of a WiFi router, and simulate how the electromagnetic waves propagate - see an example here:

http://www.gfycat.com/ImportantSafeBlackmamba

This is based on a recent blog post 'Helmhurts' at www.jasmcole.com, which was featured on io9, Ars Technica, the Daily Mail, Scientific American and many other blogs.

This app uses the 2D Finite Difference Time Domain method to solve Maxwell's equation on a Cartesian grid. An example floorplan is included in the app.

How to use:

Your floorplan needs to be a .png file, with empty space marked black and materials marked with colours. Images will be converted into the correct materials on loading - this may take a few seconds.

Pixels are mapped to 1 centimetre, so scale the floorplan appropriately.

The simulation is limited in speed due to the mobile processor, so try to keep images below approximately 500x500 pixels

Touch the image to set a router location, marked by a red circle. Select the antenna parameters at the bottom.

Set the number of iterations to run for, how often to plot the result, and the upper limit on the colourmap scale.

Choose a field to plot - the default is the out-of-plane electric field.

Click run and the simulation will begin. Click stop to pause at any time - this saves the simulation progress which can be continued by clicking run again. To reset, open an image again.

To save the simulation output as an image, click Save at any time. Images are saved to internal/external storage and added to the end of the camera roll.

To start recording a simulation click the record 'R' button. When the simulation is stopped a GIF animation is generated.

Under the bonnet:

An antenna oscillates at 2.4 GHz. The edges of the image use absorbing boundary conditions as in Mur 1981, IEEE Transactions on Electromagnetic Compatibility.

Where walls are defined, the relevant refractive indices and loss tangents for 2.4GHz radiation are used.

Wavelength and resolution are currently constant, this may change in a future release.


Disclaimer:

This app is not intended as a replacement for existing EM simulation software packages.
As a 2D approximation including only simple walls it does not accurately model a given floorplan.

It is, however, a bit of fun and entertaining to play with.

Recent changes:
Added share options.
Added ability to specify different materials.
Updated refractive indicies and loss tangents.
Fixed string parsing bugs in simulation paramter input
Fixed interface for users using large system fonts
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$0.84
78
3.9
User ratings
258
Installs
10,000+
Concerns
0
File size
876 kb
Screenshots
Video of WiFi Solver FDTD Screenshot of WiFi Solver FDTD Screenshot of WiFi Solver FDTD Screenshot of WiFi Solver FDTD Screenshot of WiFi Solver FDTD Screenshot of WiFi Solver FDTD
About WiFi Solver FDTD
With this app you can take a floorplan of your house, set the location of a WiFi router, and simulate how the electromagnetic waves propagate - see an example here:

http://www.gfycat.com/ImportantSafeBlackmamba

This is based on a recent blog post 'Helmhurts' at www.jasmcole.com, which was featured on io9, Ars Technica, the Daily Mail, Scientific American and many other blogs.

This app uses the 2D Finite Difference Time Domain method to solve Maxwell's equation on a Cartesian grid. An example floorplan is included in the app.

How to use:

Your floorplan needs to be a .png file, with empty space marked black and materials marked with colours. Images will be converted into the correct materials on loading - this may take a few seconds.

Pixels are mapped to 1 centimetre, so scale the floorplan appropriately.

The simulation is limited in speed due to the mobile processor, so try to keep images below approximately 500x500 pixels

Touch the image to set a router location, marked by a red circle. Select the antenna parameters at the bottom.

Set the number of iterations to run for, how often to plot the result, and the upper limit on the colourmap scale.

Choose a field to plot - the default is the out-of-plane electric field.

Click run and the simulation will begin. Click stop to pause at any time - this saves the simulation progress which can be continued by clicking run again. To reset, open an image again.

To save the simulation output as an image, click Save at any time. Images are saved to internal/external storage and added to the end of the camera roll.

To start recording a simulation click the record 'R' button. When the simulation is stopped a GIF animation is generated.

Under the bonnet:

An antenna oscillates at 2.4 GHz. The edges of the image use absorbing boundary conditions as in Mur 1981, IEEE Transactions on Electromagnetic Compatibility.

Where walls are defined, the relevant refractive indices and loss tangents for 2.4GHz radiation are used.

Wavelength and resolution are currently constant, this may change in a future release.


Disclaimer:

This app is not intended as a replacement for existing EM simulation software packages.
As a 2D approximation including only simple walls it does not accurately model a given floorplan.

It is, however, a bit of fun and entertaining to play with.

Recent changes:
Added share options.
Added ability to specify different materials.
Updated refractive indicies and loss tangents.
Fixed string parsing bugs in simulation paramter input
Fixed interface for users using large system fonts

User reviews of WiFi Solver FDTD
Write the first review for this app!
Android Market Comments
A Google User
Oct 27, 2014
Great App overall The app is great and I understand the limitations on size as simulations tend to take a LOT of ram. I find it very useful and helped me solidify the argument that our internet provider (building wide) had not properly placed routers around and I barely had signal in my flat (dorms). The reason I am not giving it 5 stars is because at home we have a 5hz system and I would like to work on the placement of that too. I also understand that some people would like to have a 3 antenna option. More as questions to the developer: Am I missing anything? I cant find a legend to know the signal levels (aka, at what colour is the dropoff enough to give you bad signal). Is it possible that in the future we can get options to input antenna angle? Bottom line is: great app and I would give it 5 stars if not for the 2 minor things I mentioned. As of right now I would give it 4.5 stars but google wont let me, hehe.
A Google User
Oct 23, 2014
Great, but has issues Works as advertised. If you bought a house - look in your appraisal for floor plans. Could use 5ghz wireless network functionality. My biggest gripe is pixel mapping. Why on earth map 1 pixel to 1 cm? if the max recommended size is 500 x 500, that means the maximum simulation this can handle is one single large room. About 16 foot x 16 foot. Really..?
A Google User
Oct 16, 2014
Great app! Would love to have the option of having 3 antennae on the router as well (mine does), but still, awesome app! 10x
A Google User
Oct 7, 2014
Good app. However, I think it would be possible to speed up the simulation. On my phone the app uses only ~20% of the CPU (most likely it is limited to one core). Also, for the demo video it might be useful to show touches (developer option), so that its visible which buttons are pressed.
A Google User
Oct 5, 2014
Great simulation tool A great addition would be a blueprint builder.