Tuesday, May 30, 2017

Brewing beer with a Sous Vide cooker, Round 2



I decided recently to make another go at brewing beer with my Anova Sous Vide cooker.  The first time went pretty well, but I had a few new ideas I wanted to try this time around.

Last time I found that the grain bag had a tendency to get pulled into the impeller on the sous vide cooker.  It tended to happen slowly but I had to keep checking and move the bag away from the impeller.  I thought trying to partition the brew pot with a stainless steel grate might fix this problem, so I got a stainless steel cooling rack and tied it into place in the brew pot.

I also found that every time I wanted to brew with the sous vide I had to do a page of hand calculations to make sure that the batch would fit in the pot and still fall between the min and max line of the sous vide cooker after adding grains.  To help with this problem I created a simple javascript calculator to do all the tedious calculations for me.  The calculator is available here and is free for anyone to use.  Let me know if you use it and have any feedback.

The beer I brewed turned out well but the conversion efficiency was a bit low because I had too much grain in the pot.  I failed to account for how little room there would be in the pot after installing the partition.

I learned alot from this batch and my new ideas worked out reasonably well.  The partition system worked very well besides my failure to account for the reduced grain capacity with the partition installed.  To help with this in the future I added a partition percentage option to my calculator so that I can avoid having a grist to water ratio that is too high for good conversion efficiency.

Friday, May 12, 2017

Donut Counting with LabVIEW and BeagleBone Black



While creating tutorials for the LabVIEW Web Services feature of LINX, I needed a simple real-world example application.  I think I came up with one of the dumbest possible projects to serve that purpose.

Where I work, there is a long-standing tradition to bring in donuts when making some announcement.  So when we released LabVIEW support for Raspberry Pi and BeagleBone Black devices, I wanted to combine donuts with one of those devices in some way.  I also wanted to make the project electrically simple and easy from a software perspective as well.

What I came up with is a BeagleBone Black serving up a web page that shows how many donuts are remaining in a donut box.

The circuit is super simple, it's just a photo-resistor hooked up to one of the analog inputs of the BBB.  The LabVIEW application detects that the box lid is open or closed based on reading the resistance of the sensor, and then implements a simple state machine that decrements a counter when the box lid is opened and then closed (I assume that each person is only taking one donut).  The LabVIEW app then serves up a static web page that displays the current donut count that accesses the current counter value via a LV web service.  There is also a LV web service method that allows you to set the current count value so you can input the initial number of donuts in the box.



It's definitely a silly toy application, but I think it serves as a simple example of LabVIEW Web Services that interfaces to real-world I/O.  All of the source code is available on github.