Sample photobooth photostrips

Photobooths are popular at many types of social events, including weddings, birthday parties, and school dances. However, renting one can easily cost upwards of $1000, making them impractical for many events. So when a friend mentioned wanting one for her wedding, I jumped at the opportunity to build a low-cost DIY photobooth.

To make my photobooth cost-efficient, I decided to use a thermal receipt printer to print out black and white photo strips, which eliminates the need for an expensive photo printer and photo paper/ink. I also added Twitter integration so the photobooth can tweet out every photo strip it takes, and a QR code generator that prints a link to the corresponding Twitter post on each photo strip.

The BeagleBone Black single-board computer seemed like a perfect match to power this project, and I decided to script everything in Python to keep it simple. Gphoto2 provides the camera interface, CUPS handles the printing, and Python libraries take care of everything else.

Lets get into the details of how this thing works.

Electronics

BeagleBone Black

The BeagleBone Black will boot up into a usable state without any setup required. However, I found that some gPhoto2 functions did not work with the Debian install that came preloaded on my BBB. To solve this issue, I switched to Arch Linux ARM. Instructions on installing Arch on the BeagleBone can be found here.

The basic features I wanted the photobooth to have are user input to start a photo sequence, camera control to take pictures, Twitter communication to tweet photos, and support for printing the final product. Thankfully each of these features is relatively easy to implement with Python.

I used Python 3 to allow support for some newer Python libraries. Unfortunately, this eliminated the possibility of using Adafruit’s Python GPIO library, which is only compatible with Python 2. Instead, I used the manual approach of exporting the GPIO pins to files in the /sys/class/gpio/ directory and reading the pin status values from the files. In Python, it looks a little something like this:

import io

# export pin 7
f = open('/sys/class/gpio/export', 'w')
f.write('7')
f.close()

# define pin 7 direction as input
f = open('/sys/class/gpio/gpio7/direction', 'w')
f.write('in')
f.close()

# read pin 7 status
f = open('/sys/class/gpio/gpio7/value', 'r')
status = f.read()
if("1" in status):
    # do something
elif("0" in status):
    # do something else
f.close()

# unexport pin 7
f = open('/sys/class/gpio/unexport', 'w')
f.write('7')
f.close()

The GPIO pins can be used to capture button presses and trigger the photo sequence.

The primary function of a photobooth is to take pictures, so if nothing else we’re going to have a camera in the setup. The Gphoto2 library takes care of camera integration and simplifies it down to just a few commands. The library supports thousands of camera models, so chances are your camera will work. A list of supported cameras can be found here. Since I wanted to take 4 pictures in a row with even spacing and immediately download the pictures, I used the following command and arguments:

gphoto2 --capture-image-and-download --interval=3 --frames=4 --filename /tmp/portrait%n.jpg --force-overwrite

The arguments can be modified to fit various needs—for example, saving the photos on the camera’s internal memory after they have been downloaded.

I wanted to display live view from the camera on a monitor that would allow users to see themselves as they pose for pictures, but I wasn’t able to get this working. Gphoto2 seems to turn off live view on my camera after the first picture is taken, and it won’t come back on until the camera is power-cycled. I will be working to find a solution for this issue in the future, possibly by streaming the live view video to the BBB and displaying it from there, or by replacing the camera with a high-def web cam, but until then I will live without it.

To give the user feedback when each picture is taken (in the absence of live view), I decided to turn on the camera flash, even though using the built in flash is less than optimal. Without this feedback, it is difficult to tell when each picture is being taken and when the set is finished. To minimize the blinding effect a bright flash tends to have, I turned down the flash brightness to around a 16th of its usual strength.

Because a photobooth tends to be fairly dark, and since I wasn’t relying on the flash for full lighting, I added some extra lighting to the setup. I decided to use Protofusion’s Luma lighting system to give me flexible control over the lighting through the BeagleBone Black. This allowed me to easily set the lighting levels and give some additional feedback regarding program state or errors by flashing the lights different colors. Using the Luma LED Strip Driver and an LED strip, I was able to string lighting around the top of the booth and light it with a soft, distributed light. In the absence of such a high tech lighting system, any standard light source could be used. If the light source tends to be direct and harsh, I would recommend some type of diffuser to distribute and soften it out a bit.

DYMO 400 Printer

I picked the Dymo 400 Labelwriter to print the photo strips because I could find it on eBay for pretty cheap, and it seemed widely used and supported. To use it with the BBB, I installed the CUPS printing system and found the Dymo driver in the Arch User Repository (I recommend Packer for installing packages from the AUR). Here is a good tutorial on installing and configuring CUPS.

To make the Dymo 400 print the way I wanted, I had to make a few tweaks. When I chose the “Continuous Feed” paper option in CUPS, it would print a large margin at the top of strip, so I tried setting a custom paper size. No matter what custom paper size I set, the printer would always print out the strip, and then print out an equal amount of blank paper. There may be a solution to this, but I was unable to find it. So the work around I used was to manually change the default printing settings for the printer, by going through the printer configuration file and changing the printable area for the “Continuous Feed” paper option. The modified file can be found below.

To format the individual photos into one photo strip, along with some text and a QR code at the bottom, I chose the ImageMagick command line image editing tool. I used the convert -append command to assemble all the photos into one image. The one problem I found here was that the large photos taken by the camera were too large for the program to combine into one with the limited RAM on the BeagleBone. Instead, I resized each of the photos and then assembled the smaller images. Since the Dymo 400 printer has a printable width of 672 pixels, I converted all the images down to that size. Here is the sequence of commands I used to assemble a photo strip:

# resize each of the pictures and add a border to make them go together nicely
convert /tmp/portrait1.jpg -sample 26% -bordercolor '#FFFFFF' -border 2x20 /tmp/portrait1.jpg
convert /tmp/portrait2.jpg -sample 26% -bordercolor '#FFFFFF' -border 2x20 /tmp/portrait2.jpg
convert /tmp/portrait3.jpg -sample 26% -bordercolor '#FFFFFF' -border 2x20 /tmp/portrait3.jpg
convert /tmp/portrait4.jpg -sample 26% -bordercolor '#FFFFFF' -border 2x20 /tmp/portrait4.jpg
# put the pictures all together and add the protofusion logo
# this is the version I tweeted
convert -append /tmp/portrait1.jpg /tmp/portrait2.jpg /tmp/portrait3.jpg /tmp/portrait4.jpg /root/protofusion.jpg /tmp/twitter.jpg
# resize the QR code
convert /tmp/qrcode.jpg -sample x245 /tmp/qrcode.jpg
# add the QR code and some text together horizontally
convert +append /tmp/qrcode.jpg /root/photoboothtext.jpg /tmp/qrblock.jpg
# add the QR code and text to the photo strip
# this is the version I printed
convert -append /tmp/twitter.jpg /tmp/qrblock.jpg /tmp/print.jpg


In order to Tweet photos, the photobooth needs to be connected to the internet. I used a TP-LINK TL-WN722N wifi dongle I had laying around, but any of the adapters on this list as well as many others should work well. The Arch Wiki details the steps for connecting to a wifi network in Arch Linux.

Twitter integration adds a fun twist to the traditional photobooth. I used the twython Python Twitter API wrapper, which simplified many of the steps. The only tricky part is authenticating through Twitter’s three step authentication process.  I haven’t yet added authentication support to my script, so I just manually hard-coded in the generated keys needed. I hope to add Twitter authentication to the next iteration, and will write about that when I finish it.

To give users an easy way to find their tweeted photos, I used a Python QR code generator called qrcode that generates a QR code with a link to the posted image. The generator takes the link returned by the Twitter API and spits out a QR code which is saved and appended to the photo strip. I also added some custom text next to the QR code to explain what the QR code links to.

You can find my Python code here: photobooth.zip
You can find the cups printer config file I used here: printer_config.zip

Here is a list of the tasks (detailed above) that need to be completed to set up the full system:

• Install Arch Linux
• Install Packer
• Install Python
• Install Python libraries:
  • twython
  • oauthlib
  • qrcode
  • pyserial
• Install and configure Cups
• Install and configure printer drivers
• Setup wifi connection
• Install Gphoto2
• Install ImageMagick

Physical

The physical aspect of the photobooth was the easiest part to build, although my simple design has the potential to be greatly improved. To create the enclosure, I opted for a simple PVC pipe frame that could be quickly disassembled and easily transported. I made the enclosure 6 feet long, 4 feet wide, and 6.5 feet tall. These dimensions can be adjusted based on application, but I wanted plenty of space in mine for several people to stand and pose. So far, up to seven people at a time have successfully fit in it. The length really depends on the type of camera and focal length being used, but 6 feet seems like a good starting place. The height is also highly variable, especially if people will be sitting. But since I designed with standing in mind, I wanted to accommodate some of the taller potential users.

I chose ¾” PVC as a good compromise between cost and strength, and was able to find the elbow pieces I needed to assemble a cube. Here is the design I used for the frame:

Photobooth frame made with PVC pipe

Once the frame was built, I chose curtains to cover it. Curtains are a slightly more expensive choice than some of the other options (bedsheets, etc.), but they come pre-made in various lengths, with loops in the top that make them perfect for hanging on PVC. I chose black to create a more private feel in the booth, but in hindsight, something lighter may have allowed better contrast in the photographs and prints.

When I was looking to find some sort of button to use to trigger the photo sequence, I came across a round foot pedal from a tattoo machine. This worked especially well because the booth is designed to be used standing up. However, any type of input could be used to trigger the sequence.

Photobooth instructions

The photobooth setup also needs a tripod, or something to hold the camera. I used this tripod and was really happy with it. Lighting is also important in a photobooth, so some sort of fill lighting would be desirable. As mentioned above, I found a fancy solution to this, but any light source should work. I also found that some people tend to be confused no matter how straightforward the interface is. Although it may seem tacky, an instruction sheet can really clear up confusion, and when creatively designed, can blend in seamlessly with the look of the booth.

A photobooth can help create spontaneous and memorable moments at any party or get-together. I hope the details here will inspire someone to build their own, because sometimes it’s more fun to do it yourself!

Materials

Here’s a list of the materials I used to make the photobooth, along with an idea of what they all cost.

• Beaglebone Black x 1 = $65
• USB hub x 1 = $15
• Wifi adapter x 1 = $18
• Thermal printer x 1 = $30
• Receipt paper x 4 = $24
• Foot pedal x 1 = $12
• Tripod x 1 = $20
• PVC pipes x 10 = $25
• PVC connectors x 12 = $12
• Curtains x 6 = $60

Total = $281

Already had:

• Camera
• Lighting

Tools:

• Hack saw
• Screw drivers
• Wire cutters
• Computer

I acquired a free Sigma 24-70 f/2.8 lens that had a few issues–namely, autofocus was broken and the zoom was incredibly hard to turn. After using the lens in full manual for a while, I determined that I would attempt to repair it.

I first did a quick disassembly of the mount, exposing the autofocus motor and the top of the lens components. It was clear that the metal bracket on the AF/MF switch was broken, one of the metal arms that push down the gear was dangling from the bracket. I removed the bracket and mixed up some J-B weld to glue the pieces back together.

After some googling, I determined that the lens must have already been disassembled for repair (made apparent by scuff marks on screws) as the spring that engages AF was on the wrong side of the gear. This resulted in the bracket pushing down on the gear rather than pulling it up against the spring’s force, causing the bracket to break.

After gluing up the bracket, I continued disassembly to see if I could do anything about the sticky zoom. Taking the remainder of the lens apart was tough, as Sigma lenses have soldered-on ribbon cables instead of nice detachable ribbon cables like all Canon lenses have. In addition, you must remove a single setscrew to take off the zoom ring which is hidden under the zoom ring’s rubber grip.

When removing the bottom of the lens, I pulled a bit too hard and ripped the aperture drive motor ribbon cable–I didn’t even notice I had broken it until I looked inside the disassembled lens body. Be incredibly careful when pulling apart separate pieces–these ribbon cables are very fragile! I left the aperture cable broken for the time being, as it will take a fairly long amount of time to solder back up. Note: be very careful when removing focus/zoom rings from your lens, zoom/focus encoder brushes are also very fragile.

When I reached the zoom portion, I found several small plastic bushings which were apparently crushed. The previous owner of the lens must have dropped it, crushing the bushings and skewing the alignment of the zoom. Several screws for these bushings were loose, and tightening them did make the zoom a bit easier to use. However, I could not do any more to fix the stuck zoom issue.

I also noticed that the encoder brushes for the focus assembly were bent and broken. I attempted to bend these brushes back in, but I was largely unsuccessful. I couldn’t find any replacement brushes online that matched the brushes in this lens, so I left them as-is. Interestingly enough, AF worked fine without the encoder brushes.

After waiting for the J-B weld to cure, I reassembled the lens with the spring in the right location and tested it out. AF worked properly, and the zoom was a bit easier to use. Other than the aperture being stuck at F/2.8, this was a very usable lens.

I have since repaired the broken aperture cable, and I’ll throw together a post on that procedure in the near future.

With a couple bucks worth of cheap macro filters, you can get great macro video and photos with the Canon S3 IS (works with the S1 or S5 IS as well). All you need is a lens adapter that fits all of the canon S* IS models and a set of dirt-cheap filters.

I recommend this filter set from “Digital Concepts”. Despite the cheapness of the filters, the optical quality is quite decent. I haven’t noticed much in the way of blurry edges on any photos I’ve taken, although many reviewers have noted edge blur and a bit of chromatic aberration on some macro filter sets. If you’re looking for a much better quality lens, check out this Raynox.

Taking macro video requires that you not zoom in very far while taking video. The less magnification you use, the more you can zoom.

You can take very close shots using the camera’s super-macro mode and the macro filter (the 10x filter works quite nicely). You can also use the standard macro mode, and actually zoom in and still get great macro shots, even with the 10x macro filter. This has given me great results, it also gives an incredibly shallow depth of field. The shallow depth of field is a bit intense at F8, but it can produce some really interesting effects.

Sample Images/Videos:

• Macro Video Test (pardon the bad camera-holding)
• LED Display: 10x Filter + Circular Polarizer
• Chip: 10x, no CirPol, F8 or so
• PCB: 10x, no CirPol, F7
• Coffee Mill: 10x, F/2.7
• Caterpillar: 10x, F/2.7
• Fire: 10x, F/3.5

All of these photos/videos were shot on my S3 IS with the 10x macro filter