Contact Us

8 thoughts on “Contact Us

  1. paul

    Hi guys. I came to your website from the support section of the wp tiles wordpress plugin. It looks like you had a similar issue with the tile sizing and layout in i.e. to what I am experiencing now. How did you get it to work? Thanks.

  2. Algen


    I can’t find any contact info in the site so forgive me for using the comment section. I’m Algen, I work with engineering website and would love to do an exchange of website links and feature you as a site of the day on EEWeb. Is this of interest to you?

    Hope to hear from you soon.


    Algen Dela Cruz

  3. Steve Avery

    Hi Guys
    I came to your website whilst gathering information regarding arduino microcontrllers and code of self balancing platforms, although in my case I am endeavouring to build a ‘stable’ radio control model hydrofoil, with submerged foils. I note that you already have have some afinity with hydrofoils. The main issue is height sensor. For a scale model this may only be 0 to 250mm, that conflicts with local wave height, even on sheltered pools. Do you have any comments or suggestions, for the height transducer and the code and control elements for the stabilising of the platform on submerged foils , in pitch, roll and yaw.
    Many thanks


    1. admin Post author

      Hi Steve,
      If you’ve not seen it already, you might find this paper interesting:
      In addition to the sensors mentioned there, we would also suggest looking at a capacitive sensor, measuring the capacitance between the hull and the water. As you say, the main issue will be filtering out the wave variation. I would expect that a control algorithm relying mainly on an internal IMU (accelerometers and gyroscopes) for balance/stability would be most successful and only using the low frequency component of the signal from the height sensor to ensure the average ride height is correct.
      It sounds like a very interesting project, please let us know how you get on or if we can be of any more help.


  4. Ben

    Hey Guys I would like to know what happens to your projects once you are finished. Specifically the ride on powertool drag racer?



  5. Ptoliporthos

    I was wondering if you could share the sources you used to build the aragoscope for your instructable. I’ve been trying to find some of the equations you used to determine the parameters of the aragoscope (disc size, distances, resolution, exposures, etc) but most sources are pretty thin on this.

    1. admin Post author

      Hi, sorry for the delay, spam filter seems over-exuberant.
      Aragoscope details themselves are thin on the ground. I was inspired by the Cody’sLab youtube video. But he doesn’t give much in the way of numbers beyond the separation distances and the fact it is a can lid. Then I searched the web and found the Webster Cash et al. paper on the Nasa site That didn’t help much either! I then contacted Cody on Patreon and he said he used trial and error, as he couldn’t find any equations. So then I got going myself and tried to piece it together from the paper, Cody’s video and a whole Wikipedia full of optics…

      First things first, I replicated an Arago spot as per the instructable, mostly to get a feel for how it behaves with different separations and different sized balls/discs. That allowed me to confirm a suspicion I had. The Wikipedia page for Arago spots shows that the spot is the same intensity as the brightness at the rim of the disc, and the spot is an Airy disk whose size is determined by the lens disc size (in the same way as the diffraction limit of the circular aperture of a telescope). So the peak intensity is independent of disc diameter but the larger the lens disc the smaller the Airy disk, so larger lens discs ‘focus’ less total light onto the image plane. Therefore going very large with the disc will give very little light at all, but going small gives low resolution. The image is an extended set of Arago spots from each ‘point source’ in the image plane, which are always formed, regardless of separation, so the distances don’t need to be focused, it will always image at the diffraction limit. Magnification can be calculated by similar triangles, just like a single lens set up. The ratio of the distance from the disc to the image plane over the distance from the subject to the disc gives the magnification. Exposure can be set up by trial and error, but you need the light source to illuminate the disc sufficiently that a spot of that brightness will be detectable on the sensor, both in terms of absolute brightness and in terms of brightness above the stray light illumination of your environment.


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>