Raspberry Pi Powered Long Exposures

So last time we looked at time lapse of the wheel and now we will take a look at long exposure.

A long exposure is when you are allowing the sensor to be exposed to light for an extended period of time. Anything moving like cars driving down the street with the lights on will become blurry… At least that’s what we want. Normally when you take a photo it can be a fraction of a second in a well lit room. But if you turn the lights off to get the same photo you would need to increase the time the sensor is recording and thus anything moving will blur, or if you use the same settings as the lit room picture, your picture will simply be black.

In DSLR photography we have 3 settings we can control to adjust the amount of light reaching the sensor.

  • ISO: Is an old standard from the days of film photography which is how the film will chemically react to the light. These days its all digital but the principle is the same. In digital terms its how the sensor will react to the light. The lower the ISO (ie ISO 100) the more light is needed to make a clear exposure and also the cleaner the picture. The higher the ISO (ISO 6400) much less light is needed but then also the grainier the picture has become.
  • Shutter Speed: Is how long the shutter curtain is open exposing the sensor to light. The quicker the shutter speed the more still the picture will be. But the slower the shutter speed is you start to get blurry images and you will likely need a tripod.
  • Aperture: Is controlling how much light is coming into the camera, in a normal camera lens this is normally thorough an iris. The larger the opening of the aperture the more light is received

That turned into a little photography 101! To finish, these three setting used together can create different effects in photograph. If you have a quick shutter speed you can adjust the ISO and the Aperture to make your picture expose correctly look great (depending on your lighting arrangement).. There is a wonderful book written by Bryan Peterson called Understanding Exposure I recommend if you want to learn more about exposure and photography.

Now how does this work with the Rasepberry Pi! Well 1st we need to consider what we have on the camera and understand its limitations. We don’t have an aperture to control its fixed at f2.3. The best ISO we can get from the camera board is ISO 100. Also the Shutter Speed wont go any slower than 6 seconds as its limited by the firmware.

So we want to make a long exposure. We want to take it at night to get those trailing lights! Then we will need the following things.

  • Configured Raspberry Pi with Raspbain (updated)
  • Camera board
  • Tripod (or something you can stick the camera too so its not moving)
  • Connection to the pi..
  • If you are working through a window you need something black to surround the camera to stop reflections)

In my example (below) I had set up the camera on a tiny tripod I had and put it against the window. I then used the following command to take the picture.

raspistill -hf -vf  -ss 2000000 -ISO 100 -sh 50 -br 50 -sa -75 -o wheel.jpg

A quick brake down of all the options are :

  • -hf -vf : I had my camera upside down so these settings are for horizontal and vertical flip.
  • -ss 2000000 : shutter speed at 2000000 nano seconds or 2 seconds.
  • -ISO 100 : because we have exposing the sensor for 2 seconds we need to have the lowest ISO number so that the quality is crystal clear and that the light does not blow out. If we used a higher ISO number with this shutter setting the picture would be brighter.
  • -sh 50 : Sharpness (optional) controlling the sharpness of the finished image.
  • -br 50 : Brightness (also optional) controlling the brightness of the finished image.
  • -sa -75: Saturation (again optional) controlling if the image is color bright or washed out.
  • -o wheel.jpg: output with the file name.

Here is the image I manged to get

B3zhQCZCIAEsRg6

In this image example using ISO 100 and Shutter speed as 2 seconds we can use this as a reference to what would happen if we started to fuss with the options.

  • If we just simply change the Shutter speed to 4 seconds the lights in the image would become brighter but the light trails would get longer as we are recording more of the movement.
  • If we put it to 6 seconds then the lights would loose all color and would turn white!
  • If we changed the image to 1 second the trials would be shorter the image would get darker.
  • Returning the Shutter speed to 2 seconds if we made the ISO 200 the image would become a little more grainy and brighter but the light trails would remain the same as the image above.
  • If we set the ISO to ISO 800 the image quality would be really grainy and the image would be almost white. But the light trails again would be the same as the 2 second Shutter speed is always the same.

Best thing to do is sit down next to your pi and play around with the options until you get what you feel is right.

I hope this helps in working out how to make a long exposure and if you have the time/money please do check out Bryan Petersons Understanding Exposure its a really great read for those starting out in photography

Please do feel free to comment with your examples of Raspberry Pi Powered Long Exposures!

 

 

Wheely – Time lapse write up

I am a massive fan of photography and especially time lapse photography so when I spotted a Christmas market setting up a Ferris wheel across the road from my 7th floor office, I jumped for the most logical (and quiet) tool for a time lapse. The Raspberry Pi!

Here is a super quick write up of what you would need and also what I did (and did wrong) on this little adventure.

What you need:

  • Raspberry Pi + power, sd-card, case etc… Installed with raspbain
  • Pi Camera board
  • Some sort of tripod (but this can even be hot glue and something that stands up)
  • Mass storage device – USB stick or Hard drive (powered)

Step One: Find a location to shoot

I was indoors so I have to find a window where I could set the camera up. I had to consider the reflection so it was a good idea to make everything black. I have the Camera mount from pimoroni which is black and with black screws.  otherwise I just covered everything else in a black cloth.

This image is an example of reflection in action (sucks!)

runningwheel-reflection

If the time lapse is at night then try and reduce the light behind the camera so you don’t end up with a massive network cable in the sky!

Step Two: Setup the camera and make a test shot

I used my laptop to SSH into the Raspberry Pi where it was so I could walk away and leave it running without any screens or keyboards waiting to trip anyone up.

To test the camera was working I made my 1st shot using the following command:

raspistill -o /home/pi/test.jpg

which gave me this image (without the reflection)

xmas2_flipped

(the blur is water on the window nothing I can do but can look interesting with light intersecting it)

I had to rotate the camera and flip the image so that everything looked as it should  on the output screen. You could just turn the camera but where is the fun in that.

raspistill -hf -vf -o /home/pi/test.jpg

hf = horizontal flip, vf = vertical flip

xmas2_0003

Now we are cooking!

Step Three: Attach mass storage device and MOUNT IT!

First make a new folder

mkdir /media/timelapse

Then you can plug in your hard drive and type the following command (assuming sda1 is the drives Identifier)

mount /dev/sda1 /media/timelapse

This now means the anything on the hard drive can be seen in the folder /media/timelapse and in turn you can save to /media/timelapse and it would be on the hard drive.

Yeah well this is important and where I slipped up. When running a pi with the desktop environment any USB stick or hard drive you connect would be mounted automatically. So half way though the timelapes I had to unexpectedly restart the pi… and forgot to re-mount the hard drive!

Why did I use hard  drives instead of cloud or online storage… My office wont allow this device to be connected to our network.

Step Four: Start the timelapse

There are a few ways to do this..

I went with the -tl option.

My command looked like this –

raspistill -hf -vf -o /media/timelapse/wheel_%07d.jpg -tl 30000 -t 604800000

so -tl is 30000 milliseconds (30 seconds) meaning it will take a picture every 30s for -t 604800000 (7 days), the file name has %07d which means the file name will have 7 digits for example: wheel_0000001.jpg this will increase until wheel_9999999.jpg

So at this point check its all working and your happy!

Step Five: Ignore and get on with life

Note: I did not use any magic lenses or changed any settings to adjust for lighting. All that I am experimenting with now.

Step Six: Compile your photos

Ok so this is where I cheat and don’t use the raspberry pi. The data you would be pushing to make the finished video is massive, especially when your compiling 7 days worth of photos at 30s interval’s.

I found a neat tool for MacOS called Time lapse assembler. Its a simple application where you point it to a directory tell it the frame rate and quality, have a couple cups of tea and its done.

I used this app because while the pi is capable of compiling the time lapse when you start running into the 1000s of files, then its just better and safer to use a desktop system like a Macbook.

Step Seven: Upload and share

Well that’s a given right!

In the end this is a quick overview of what I did. I would totally recommend you to read the tutorials on the raspberrypi.org/resources page I mentioned before as they do a really great job to show you by example how this can work.

Please feel free to leave a comment with how you get on or any questions. Share your results also!

Review + Unboxing of the U-Create Raspberry Pi Model B+ Plug ‘N’ Play Kit

Here in Berlin I am continually looking to push the Raspberry Pi to the German education system and to that end I wanted to take a real good look what educational kits are available and what is best to recommend.

Some of the points I am looking for are:

  • User Guide (so the user is not left alone with the Pi)
  • Complete Kit (nothing worse than missing a cable)
  • Robustness
  • Fun Factor
  • Education Value
  • Bonus items (sometimes its nice to get a sticker)

My good friends at http://cpc.farnell.com/ sent me a couple of their kits to take a look and I wanted to share with you my finding.

One kit was the Raspberry Pi™ Model B+ Plug ‘N’ Play Kit. Below is a full review of the kit and an unboxing video!

I was really pleased with the contents of this kit. You had everything you need to get started with the Raspberry Pi with the exception of the monitor of course. I was very pleased to see WiFi and Ethernet cable in the same kit. Often I found that kits like this don’t provide networking cables simply because they are not expected in the home. Yet this covers the possibility that there is no good wifi signal or simply the school does not allow WiFi for security. Also considering headless setup its nice to have the feeling that its taken care of within this kit.

The user guild booklet I found short but to the point. Your given the maximum amount of information you need to get started but without being bogged down with a 150 page book. I loved the fact that the booklet also does not just tell you to get from the box to Raspbain but rather tells the user about other Linux distributions so you could make an informed choice. Lastly I specially found it welcome to see the Pi-Store documented in this booklet. I don’t see that very often which is a shame because it is a great resource for budding programmers.

In terms of fun factor… I did find all the cables a little bland. By no means is this a deal beaker for me. Remember I am looking at this from a educational point of view. One where the teacher would look to supply their computing lab with pi’s, then this kit hits the nail on the head! What makes up for the black cables though is the optical mouse. When I plugged it in both myself and my wife where shocked to find it had a red and blue LED light inside and lit up half our room.

I think that a clear case is imperative. The kids need to see that hardware but keep it protected! So I am very pleased to see that in kit.

All in all I found it a complete working kit that’s perfect for a computing lab or as a birthday (or Christmas) gift for your kids, siblings, parents or even grandparents.

CPC also have other kits available from the U-Create brand. If your looking for just the pi and a case or start to a media center and you can find them all here at: http://cpc.farnell.com

Pushing the boat out

Its long overdue but I am finally pushing the boat out on this blog. I spent some time tweaking the template but found that nothing really sat right with me. Thus a black hole opened up sucking all my valuable blogging time away.

No more!

November 22nd will be my 5th Raspberry Jam Berlin! I am personally super excited about this because the Jam has moved to the Technische Universität Berlin (TUB). They have a super computing lab there so I am hoping to cut out all the old technical problems we had before. Also this time round I sold out tickets (I say sold out but they are actually free) so its feeling especially good!

Massive thanks to Melanie Stilz for helping me with the university and being so interested in the Raspberry Pi.

Whats happening next! My good friend Jason (aka boeeerb) sent me a couple of LED Flash boards for the Raspberry Pi-camera called: Lisiparoi

You would attach the Pi-camera to the board and when activated it would blast light in that direction. To me it feels like a mini ring flash. There is 2 versions one normal white LED and the other is for Infrared and would only work with the Noir Infrared Pi-camera.

It’s looking like a sweet little bit of tech and the photographer in my is buzzing to use it. Examples, videos and full review coming soon!

 

Something New!

Hey guys welcome to Byting Idea!

This little blog will be my home for my raspberry pi musings and review.

I hope that every Friday I will have a something up either a review, video or just a little post.

So here goes and wish me luck!

James

Me, myself and Raspberry Jam

The community surrounding the Raspberry Pi is vast and awesome! Nothing really embodies how awesome it is more than the Raspberry Jam. These events found all over the world allowing geeks and geekettes to meetup and share and learn. They are opportunities to network and find new friends and help for projects. You can also sometimes buy accessories for your Pi.

I really wanted to attend one of these events but I live in Berlin Germany, and while Berlin has an impressive list of events from Javascript workshops to Hackathons, I found that we were lacking on a regular meetup group for the Raspberry Pi. Berlin had no finger in any Raspberry Jam’s.

After pushing some ideas around and contacting some other group organizers I got to the point that I knew I would have to take the bull by the horns at get on with setting up the a Jam on my own. Red flags started to wave soon after.

  • Where do I have the Raspberry Jam?
  • What do I talk about?
  • Will anyone come?
  • What about food and drink?
  • Will there be screens?
  • Will there be a network?

These are only a few of the questions that popped into my head when starting this.

Its important to note if you’re organizing an event like this to keep yourself focused on what you need to do and be clear what you want for the people attending the event! Lists are of the utmost importance. I carry a A4 ring bound book with me marking down everything I need to do!

While finding help from twitter followers, I found a coworking office that would let me use their space. I decided on what I would talk about. I contacted companies that are related to the Raspberry Pi and asked them to help by sponsoring the Jam. I was overwhelmed by the response from everyone helping. While I might not have had someone next to me taking tasks and making notes. I never really felt alone doing this!

Since this was the first Raspberry Jam event in Berlin I thought I would simply introduce the Raspberry Pi, the foundations mission and also a short getting started guide to the Raspberry Pi. This paid off as I could see several people in the group wide eyed and their newly purchased Pi in their laps!

During the setup I did hit a few road blocks! I found out a few weeks before that the venue did not have a wired network! I did not have any compatible wifi devices to take with me. In fact only a month before I threw out an old router that could have been an access point, for sure an ‘I knew I would need that’ moment! I simply setup the a copy of raspbain on my home network and cloned the network cards. I then figured out that the monitors while having USB ports would not power the pi’s! This was the moment that could have ruined the whole Jam but thankfully I remembered to take all the USB chargers I had in the house and also my only Powered USB hub. Finally I wanted to use the camera board to make a small stop motion animation booth and let people have a play. After they took their shots the animation would complied and emailed to tumblr… But because of the Internet issues that did not happen!

Lessons learned… Always check everything before you go! Have backups if something does not work. We might all hate Murphy but his law is sound: Anything that can go wrong, will go wrong.

Thankfully I don’t think anyone noticed the issues and still enjoyed their time at the Jam.

After the talks (and yeah I did have the feeling I went on a bit), We had some cake pops my wife made and I let everyone have a go at a row of Raspberry Pi’s (donated by a sponsor) setup at the back of the room. I had laid out a selection of add-on boards and motors, minecraft and Sonic Pi all out and installed ready to use.

What I found important at this point was to capture the interest of the people attending. If I simply laid some nameless board with no instructions would they bother to even look at them. So a week or so before the Jam I made ‘Activity Cards’ which are printed and laminated A5 sheets containing instructions on how to install the add-on board or program and one simple example on how to use it.

Activity Cards

I measure the success of these activity cards by having a friend of mine that does not have a Raspberry Pi, take a card for the program ‘Sonic Pi’ and 5 minutes later I could hear ‘Stay alive’ from the game Portal fill the room!

My sponsors where a fantastic help. In fact without them I don’t think the Jam could not have happened in the form it did!

If you would like to be a sponsor or want to send the Raspberry Jam Berlin some demo boards feel free to email: raspberryjamberlin@gmail.com

I had loads of fun organizing the event, met some really cool people, helped some people with issues there were having with their Pi, helped some get setup with their Pi for the first time and most of all I got to attend a Raspberry Jam… Finally!

You can find some photos for the Raspberry Jam Berlin on Flickr and also the next event will be on the 2nd of August! More information here: raspberryjamberlin.bytingidea.com

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