IPhone Polarizing Camera Solves Filter Orientation Problem Using Flash

One of last year’s Hackaday Prize finalists was the DOLPi, [Dave Prutchi]’s polarimetric camera which used an LCD sheet from a welder’s mask placed in front of a Raspberry Pi camera. Multiple images were taken by the DOLPi at different polarizations and used to compute images designed to show the polarization of the light in each pixel and convey it to the viewer through color.

The polarizer and phototransistor taped to the iPhone.
The polarizer and phototransistor taped to the iPhone.

[Dave] wrote to tip us off about [Paul Wallace]’s take on the same idea, a DOLPi-inspired polarimetric camera using an iPhone with an ingenious solution to the problem of calibrating the device to the correct polarization angle for each image that does not require any electrical connection between phone and camera hardware. [Paul]’s camera is calibrated using the iPhone’s flash. The light coming from the flash through the LCD is measured by a phototransistor and Arduino Mini which sets the LCD to the correct polarization. The whole setup is taped to the back of the iPhone, though we suspect a 3D-printed holder could be made without too many problems. He provides full details as well as code for the iPhone app that controls the camera and computes the images on his blog post.

We covered the DOLPi in detail last year as part of our 2015 Hackaday Prize finalist coverage. You can also find its page on Hackaday.io, and [Dave]’s own write-up on his blog.

 

Horrible Macro Rig Makes Good Photos

We love horrible hacks like this. It’s a lens and a ring of LEDs, taped to a cell phone. Powered through crocodile clips, also taped to the cell phone. There’s nothing professional here — we can think of a million ways to tweak this recipe. But the proof of the pudding is in the tasting.

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First 360-degree Video From An Amateur Rocket?

Space. The final 360-degree frontier. These are the voyages of the Portland State Aerospace Society (PSAS), whose ongoing mission is to seek out new civilizations and launch rockets at them. For their latest adventure, they stuck a 360-degree video camera into their rocket. The resulting video is spectacular, from the pre-launch drama of an attack by a giant bee to the parachute release. It also works in Google Cardboard or Oculus Rift through the YouTube viewer.

The 360-degree video was made from video captured by five GoPro cameras stuck inside a custom-built module mounted inside the rocket body, then stitched together by PTGUI for the final video. The PSAS has been building modular rockets for some time, and this camera was mounted on their LV2 model. In this flight, the rocket reached an altitude of 4.7km (about 3 miles high), reaching a peak velocity of about 350 meters per second. That’s a pretty impressive height and speed, and you definitely get a good feeling for the dramatic climb of the rocket as it zooms up. This is some impressive stuff from a group of serious rocketeers who are boldly going where nobody has gone before…

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Make your Own Infrared Camera on the Cheap!

This is a super fun hack that’s been around for ages — but now with cheap full 1080P HD camera availability, it’s probably a good time to make your own infrared camera!

It’s actually a very easy modification to perform. All cameras are capable of “seeing” infrared light, but for standard photography and video, you don’t want to see the infrared light. So most sensors just have an infrared filter in front of the sensor, to block out any excess infrared light. If you remove it … you have a converted infrared camera.

The following video shows exactly how to modify a camera to do this. It is a bit misleading though as it labels it as a thermal camera; and while it is seeing “infrared”, it’s not actually full thermal infrared, like a FLIR or Seek Thermal can see — it’s a mixture of visible and near infrared light. You will be able to see some hot things glowing through the camera, but not to the same degree as a real thermal imaging device. Continue reading “Make your Own Infrared Camera on the Cheap!”

16 Megapixel Outdoor Security Camera on the Cheap

Looking for a high quality security camera? Despite digital cameras continually getting better, and less expensive, security cameras haven’t seemed to follow the same path. So? Better make your own.

[donothingloop] was looking for an outdoor, network capable camera of high resolution. He Some people might have thought about using the Raspberry Pi camera module, but let’s be honest — it’s not great. Instead, he found a pair of used Nikon Coolpix L31 cameras, and he only paid $15 for the both of them.

Now the Nikon Coolpix L31 isn’t exactly the sports edition, so to make this an outdoor security camera, it’s going to need an enclosure. An outdoor halogen work lamp enclosure fit the bill perfectly. It’s rugged, already has the glass built into it, and at $12 the cost of this project wasn’t going anywhere!

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One Hacker’s Small Tabletop Photo Studio

We love good pictures. You know, being worth a thousand words and all. So, after our article on taking good reference photos, we were pleased to see a reader, [Steve], sharing his photography set-up.

Taking good technical photos is a whole separate art from other fields of photography like portraiture.  For example, [Steve] mentions that he uses “bullseye” composition, or, putting the thing right in the middle. The standard philosophy on this method is that it’s bad and you are bad. For technical photos, it’s perfect.

[Steve] also has some unique toys in his arsenal. Like a toy macro lens from a subscription chemistry kit. He also showed off his foldscope. Sadly, they appear to no longer be for sale, but we sometimes get by with a loupe held in front of the lens. He also uses things standard in our shop. Such as a gridded cutting mat as a backdrop and a cheap three dollar tripod with spring actuated jaws to hold his phone steady.

In the end, [Steve] mostly shows that a little thought goes a long way to producing a photo that doesn’t just show, but communicates an idea in a better way than just words can manage.

 

Using Missile Tech to See Like Predator

[Artem Litvinovich] wanted to see by heat vision like in the Predator movies. He not only succeeded but went on to see in color, medium-wave IR, short-wave IR, and ultraviolet using a very unique approach since his effort began back in 2009.

He started with a box based on the basic pinhole camera concept. In the box is a physical X-Y digitizer moving a photodiode to collect the thousands of points needed to create a picture. First all he got, due to the high signal amplification, was the 60 cycle hum that permeates our lives. A Faraday cage around the box helped but metal foil around the sensor and amplifier finally eliminated the noise. Now he had pictures in the near infrared (NIR). Continue reading “Using Missile Tech to See Like Predator”