raspberry pi

Raspberry Pi 3 Mini Cluster

I recently constructed a mini cluster consisting of 3 Raspberry Pi 3s.  I am planning on using these machines for various little projects.  I’ve installed some services on one of the nodes.  Currently that node hosts Redis and RabbitMQ instances.  I’m sure that I’ll have other services to install in the near future.  I may even use it to tinker with clustering those services.  Below are some pictures of the cluster as I was putting it together and a parts list.


Posted by Chad Dotson in Raspberry Pi, Technology, 0 comments
Raspberry Pi 7″ Touchscreen Unboxing and Thoughts

Raspberry Pi 7″ Touchscreen Unboxing and Thoughts

This week I ordered and received the official Raspberry 7″ touchscreen ($60).  I’ve been tinkering with some ideas for it (some car based projects) and wanted it on hand to try out.

Opening the Box

The screen is packaged and presented really well.  It comes with all that you need to connect and power it from the Pi itself.  It comes with 4 screws to mount the Pi, the ribbon cable to connect it to the Pi’s DSI port, and 4 jumper wires, 2 of which are for powering the display on the Raspberry Pi 2 B+.  The other 2 are used when attaching the display to an older model A or B.

The Screen Itself

The screen itself seems really well made, I’m really impressed by it.  The LCD side seems pretty sturdy and the backside seems better than I would have expected.  Mine has a little give around the are the ribbons from the control board enter the LCD itself, but its nothing to complain about.

Connecting It All

In this case with the Raspberry Pi 2 B+, the screen connects easily via DSI ribbon and 2 jumpers to 5V and ground.  Once wired its an easy job to mount the Pi onto the screen.  In these pics you also see my cheap wifi and old keyboard dongle.  I think I will want to buy a good Bluetooth adapter and keyboard shortly.  I found a really need looking one here: http://www.amazon.com/gp/product/B00BX0YKX4.

Up and Running

Once all connected, the Pi boots right up to the console.  At this point you need the external keyboard to actually login and run startx, unless you’ve already configured Raspbian to do so.  You will also need to install a virtual keyboard like Florence or Matchbox.

Using It

The biggest shortcoming is the need for a physical keyboard, like I mentioned in the preceding section, and it is probably the biggest drawback.  The out of the box touch features seems only to augment physical keyboard functionality.  That’s because unlike Android or iOS, the virtual keyboard isn’t dynamic, it is either always there or not.  I suppose that a custom interface would be more touch oriented.  The one oddity I have found is that counter to other touch screens, the hotspot for a touch seems off and to me it seems more exaggerated near the edges of the screen.  It’s not a show stopper, but takes some getting used to.

Overall Opinion

After getting it all hooked up, I found that it seems a bit clunky.  It left me wondering if a better solution isn’t just a raspberry pi running as a server and using a Android or iOS device as a head.  However, assuming you stick with the Raspberry driving its own display, a longer cable might be desirable, depending on your project.  In that case a regular HDMI touchscreen with usb connections might be the better fit.

The lack of good cases is also a problem.  Nothing I have found yet, fully encloses the pi and the display.  Coincidentally, I had an old project box laying around that seems to fit almost perfectly.  At 7.5″ x 4.3″, the Hammond 1591ESBK‘s dimensions are only a little shy of the actual dimensions of the displays bezel (less than 0.25″).  I’ll post new photos if / when I do that.

Other Resources:

Posted by Chad Dotson in Raspberry Pi, 0 comments

Hardware vs Software – A Realization

I spent some time over the past year tinkering with Arduinos and Raspberry Pis and had a bit of a realization: Hardware circuit components are simply the syntax for creating physical devices.  As a software person, putting hardware into that context has really given it a lot of meaning.

Posted by Chad Dotson in Arduino, Raspberry Pi, Technology, 0 comments
My First Raspberry Pi Project

My First Raspberry Pi Project

View of the whole setup

View of the whole setup

Almost every year, I try to select a fun project to do while off for Christmas. This year the project I selected was based on Raspberry Pi.  Specifically I decided to build a device that would, when motion is detected, find the range to the motion using an ultrasonic rangefinder, take a picture using the camera module, and finally email me the results.

After just a few hours of work, I had separate proofs of concept working for each sensor written in Python.  A short time after, I started combining all the proofs of concept into a consolidated script which I got working.  Right now I am perfecting the classes for interfacing with the range finder and the motion detector and I am currently using picamera 0.8 for interfacing with the camera module.  I’ve included a link to the git repository I’m using for source control below.


  • Raspberry Pi Model B
  • Raspberry Pi 5MP Camera Board Module
  • HC-SR501 Human Sensor Module Pyroelectric Infrared
  • SainSmart HC-SR04 Ranging Detector Mod Distance Sensor
  • 5 180 ohm resistors
  • Breadboard and miscellaneous connectors

Source Code: https://github.com/chaddotson/PiPy


Posted by Chad Dotson in Featured, Hobbies, Neat Stuff, Raspberry Pi, 0 comments