New Pages: Research Equipment and Open-Source Syringe Pump

I created a new page where I offer some research equipment designs and related resources. Although most of my efforts are dedicated to conducting behavioral research, I often have to design equipment for my experiments. When I am able, I like to document these designs and make them available for others.

My first contribution is my open-source syringe pump design. I designed the pump for my research in animal behavior. It is designed to precisely deliver liquid reinforcers to animals and to be easily controlled from a microcontroller interface such as the Propeller Experiment Controller. The pump costs about $173 and can be easily assembled from ServoCity's modular Actobotics line. Only three specialized 3D printed parts are needed. I provide a full parts lists, mechanical and electronics assembly instructions, and programming suggestions.

New Object for the Propeller Experiment Controller

I created an additional frequency generator object titled "EXP_FrequencyGenerator" to supplement Experimental_Functions's frequency generator methods. This object is optional, but I found this was useful in uncommon cases where multiple high frequencies needed to be generated. For lower frequencies the PWM methods in Experimental_Functions are usually adequate. The methods in the frequency generator object work identically to the methods found in Experimental_Functions. To download this object, simply download the most recent version of the Propeller Experiment Controller. For more details, see the list of changes page. 

Propeller Experiment Controller Version 1.5: Released!

I have officially released version 1.5 of the Propeller Experiment Controller software after much testing. The Propeller Python Interface program has not been tested in detail across multiple computer operating systems, but all other components have been well-tested. Click here for a list of changes and here to download the new version of the software.

Also, I'm updating the look of the website. I think it looks a bit better.

Propeller Experiment Controller Version 1.5: Soon to be Released

I have nearly completed version 1.5 of the Propeller Experiment Controller software. I added many new features that I found were useful in my own work, or that were needed by colleagues using the Propeller Experiment Controller. I also fixed a few minor bugs. The Propeller Experiment Controller now provides good support for standard date and time formats such as "MM:DD:YYYY" and "HH:MM:SS." It now allows the user to read and write files from the SD card in any method they choose. This can be useful for creating settings files or custom data formats. The Propeller Experiment Controller can now also produce MedPC compatible data output that can be used with existing data analysis programs expecting a MedPC formatted file. Many other small changes decrease program size and increase efficiency. Click here for a detailed list of changes. I will release version 1.5 shortly after testing the code a little more.

The next goals for the Propeller Experiment Controller are to create more and better sample experiment programs for principles of behavior laboratories, create a C version of all spin code, and add methods to integrate the Propeller Python Interface with the powerful and free data analysis software package SciPy, and perhaps R as well.

New Page: Recommended Vendors

For a beginner, finding the right parts and equipment to purchase can be overwhelming. Conducting a simple Google search for parts can reveal a plethora of websites, many of which are targeted toward experienced engineers, as well as confusing data sheets. However, if you know where to look, you can find some very useful hobby electronics vendors that make shopping for parts easy and can also inspire you to form new ideas as you browse through parts listings. On this page I recommend a few hobby electronics vendors I frequently use as well as some industrial electronics vendors I use when I need something less common.

New Page: Which Propeller to Use?

After selecting a Propeller board to use for a new project, I realized how overwhelming it can be for a first-time or experienced user to select a Propeller board out of the many varieties available. To simplify the selection process, I created a guide on selecting a Propeller board to use as an experiment controller. When using the Propeller for research, we are generally interested in 5 features:

  1. The Propeller chip
  2. A way to power the Propeller
  3. A way to program the Propeller
  4. A way to connect the Propeller to devices
  5. A μSD card socket for saving data

Although every project has slightly different requirements, these basic points are useful to consider. Click here to read my discussion of several Propeller boards in terms of these requirements and ease of use.

Paraiba Brasil 2013

Recently I met with some new colleagues in Paraiba Brasil. I am pleased to say that there may be some future collaboration involving the Propeller Experiment Controller. My colleagues have a different perspective on behavior than many behaviorists in the United States and this might lead to application of behavioral technology in some areas I had not considered, particularly agriculture. I look forward to what the future might bring.

I was also fortunate to encounter a few interesting native species. I have an avid interest in herpetology and although we did not play any events to see local wildlife, I stumbled upon some interesting creatures. I might make a more detailed post at a later time, but for now, here are a few pictures:


Who doesn't love to see cane toads in their natural range? There were five large females living near one of the places I was staying. Visiting them became a nightly affair. How could anyone not be fascinated by toads this large?

Screen shot 2013-08-25 at 6.05.27 PM copy.png

I was also extremely lucky that a colleague found this boa constrictor hiding under some leaves. It was a pretty friendly snake, only trying to bite me in the face a few times when I picked it up. After it was in my hands, the snake was relaxed. I am only holding the snake's head so that others can touch it without concern. This was the first time I encountered a snake that large in the wild. Now I want to find a larger snake!

Overall, it was a wonderful trip and I hope to be able to do work in Brasil in the future.

Website Launched

The first paper on the Propeller Experiment Controller was published today, and the website is now officially open. Currently, the website is in a rather rudimentary form, but I do offer several pages related to the Propeller Experiment Controller. I will continue to add more information and tutorials related to the Propeller Experiment Controller and general apparatus design as time permits. For now, click the link below to check out the paper, or take a look at the Experiment Controller page for more information.

Varnon, C. A., & Abramson, C. I. (2013). The propeller experiment controller: Low-cost automation for classroom experiments in learning and behavior. Comprehensive Psychology, 2, 1-18. doi:10.2466/07.08.IT.2.2.