Logitech Webcam on Pi

I’ve been thinking about using a Pi at the makerspace to run some digital signage, including a big display indicating who the on-duty volunteer is for the space when we have open hours. So this got me thinking about having the persons picture up on the display along with their name and other stuff, which led to wanting a camera for the Pi that could take the person’s picture.

Digging in, it was pretty simple to get the basic webcam stuff working on the Pi. It’s not *fast*, but 1 – 2 fps is fine for verifying that it works. To get the webcam stuff running, I plugged in the webcam (a generic Logitech webcam – don’t know the model and the kernel doesn’t seem to know either) I used:

  • sudo apt-get install guvcview uvccapture
  • sudo usermod -a -G video pi
  • sudo modprobe uvcvideo

Then REBOOT the Pi. When it boots, you can start a live webcam window using:

  • guvcview

However, if you just want to capture frames as jpegs, what is tried is:

  • uvccapture -x640 -y480 -q75 

However, this turns out to give a very posterized / oversaturated / artistic crazy picture that has all the colors screwed up. What I found is that it was setting the Gain, Brightness, Contrast and Saturation to MAXIMUM values, which naturally results in crazy. Searching the interwebs turned up some decent parameters, but I found that using the following command line seemed to allow the cam to auto-expose the pictures correctly most of the time:

  • uccapture -x640 -y480 -q75 -B128 -S32 -C32 -G0

I’m not sure if these are “magic numbers” that tell the camera to try to figure out the settings for itself, but it seems to work pretty well. Below is a snapshot of the desktop running the guvcview software with some nice recursion.



February 23, 2013 at 4:26 am Leave a comment

Makerspace Launch – Snowmageddon Edition!

Today was the soft-launch / founding members event for the Tech Valley Center of Gravity Makerspace (merging the Capital District Makerspace). The original plan was for me to fly back from Photonics West in San Francisco to Albany on Friday, but mother nature and the monkeys at US Airways had other ideas. Due to the grossly overblown forecast for the Capital District of NY, my flight reservations were cancelled and I was re-booked for Sunday. So I would not be able to attend the launch event.

However, we don’t give up that easily, and thanks to a home-built audio system made by Corbin, and the power of Skype, I was able to join virtually and say a few words anyway. The long and short of it is even though the weather was unpleasant, and publicity was word-of-mouth and guerilla marketing, we had over 120+ people show up for the founding event, and signed up 55+ new members (the final official tally will have to wait until I get back). Truly amazing!

The suspicion that there was tremendous pent-up demand for a Makerspace in the Capital District has now been confirmed, and now we have to rise to the challenge of meeting that demand. I’m excited to see how the community continues to grow, and looking forward to helping make it happen!

February 10, 2013 at 3:12 am Leave a comment

Make a Makerspace workshop

I’m at the Make a Makerspace workshop being run by Artisan’s Asylum and Make magazine. Yesterday was the first full day of content, and my brain is still sore from the deluge of information. Sections on business models, business plans, safety, liability, things Not To Do (TM), and all around advice and tools for setting up a Makerspace were plentiful, and it’s given me alot to think about as Capital District Makerspace (soon to be Tech Valley Center of Gravity) prepares for our soft-launch of our inaugural location at 35 4th St, Troy, NY. 

The whole workshop has been very well organized and executed, and I hope that they make this an annual event that can help new Makerspaces get off the ground. More on this later, time to head off for breakfast and then the Sunday sessions!

February 3, 2013 at 12:29 pm Leave a comment

First Raspberry Pi Jam!

Whew! Yesterday I ran a workshop for the Capital District Makerspace at the Edison Tech Center in Schenectady on ‘Getting Started with the Raspberry Pi’. We had roughly a dozen or so Raspberry Pi’s being used, and twice as many attendees, so it was a quite a turnout for our first Pi Jam. The workshop helped everyone through the initial bootup process, establishing SSH connections into the Pi, updating and installing new software, setting up VNC access, a tour of the desktop, and finally how to use the GPIO pins to light an LED and detect a pressed button. All in 3 hours. A copy of my presentation can be found here.

With such a large group, we now have a good user community in the Capital District and we’re going to set up a dedicated forum for Pi users to ask questions and share projects. We’ll also try to make the Pi Jam a regular monthly event now that we’ve worked out all the kinks of running such an event! I think next month will just be dedicated to the different ways of using the GPIO pins to control LEDs, DC motors, Servos, Steppers and read information from sensors. That will EASILY fill another 3 hours!

January 13, 2013 at 4:23 pm Leave a comment

Bouncing Droplets Exhibit Quantum behaviors

I just found this really excellent blog called “Fuck Yeah Fluid Dynamics” which is filled with a veritable cornucopia of physics-pron. The post that clinched it for me is the demonstration that a bouncing droplet can exhibit the particle-wave duality found in Quantum Mechanics, and ties some links to early quantum theories which had a formative impact in the current theory.

January 2, 2013 at 1:37 am Leave a comment

An interesting study in economies of scale

It’s been shown through empirical evidence recently that small batches of some types of product are economically viable, and unlock a class of  potential items that would not otherwise be available because of their below-mass-market appeal. Kickstarter has definitely exposed this reality, especially in the technology section where it is possible to see consumer / prosumer / enthusiast devices being offered in volumes that are measured in the 100’s, not millions. I just can across this interesting study from Octopart that shows the total cost of a product containing a spectrum of sourced parts as a function of volume, and it’s clear that the point where scale pricing really kicks in is rather early. The study is well worth a read for anyone considering the prospect of a specialized device that might only have a market measured in 1000’s rather than millions.

December 31, 2012 at 10:58 pm Leave a comment

Tech Valley Makers Meeting – SUCCESS

The Tech Valley Makers had their first meeting on Nov 28th, and it was a resounding success! Pulled from all over the Capital District, we had over 30 people show up at Union College to talk about Kickstarter, 3D Printers and the Raspberry Pi! My feet have not hit the ground since the meeting, because a group that size means there is a substantial demand for a Makerspace in the region, and there are some opportunities to make that happen sooner rather than later, given the amount of interest out there.

For now we are piggy-backing on a web site that was set up for a prior attempt to get a Makerspace in the region, and in the next few weeks we will ratify a formal name for the group which can be used for the non-profit and all official business. For now, much of the discussion is taking place at the Capital District Industrial Club web site. 

December 4, 2012 at 5:20 pm Leave a comment

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