Saturday, October 26, 2013

3D Printing for Dispenser and Getting Back to HESA

Last night, I stopped off at the Milwaukee Makerspace to do a couple of things.

The first thing I did is 3D print the pieces that connect to the wood supports on the automated dog feed dispenser that I am making.  The 3D printer initially had PLA filament in it.  I tried printing with the PLA and it did not work well at first.  The raft printed ok but after that, no plastic was getting laid down.  I cancelled the print, removed the PLA and loaded some ABS filament that I had used before.  I was then able to print the two support pieces.  These are the last two pieces that I needed to 3D print.  Next, I need to use the CNC router to cut the wood.

While I was waiting for the two pieces to print (just over two hours), I got the Home Environmental Sensor Array project off of the shelf and started working on it again.  It took me about thirty minutes to get back up to speed and remember how everything was connected.  Almost everything worked.  The one thing that is not working is the sensor part of the circuit.  As soon as the wire from the sensor is connected to the input GPIO on the raspberry pi, the program I wrote shuts off power as if it detected power coming in to the GPIO port.

I don't understand why this is happening.  Tom G. from the Makerspace suggested that I add a resistor into the circuit.  I did that but it did not help.  Maybe I wired it up wrong.

I also read an article about reading a sensor on the pi.  Its not exactly the same thing I am trying to do but maybe the same circuit would work for me.  It has a resistor and a capacitor.  Maybe waiting for the capacitor to charge is a better way to detect the closed circuit.

I will try to document the circuit I am using now and post it to the Makerspace user forums.  Maybe someone will know what I am doing wrong.

I also need to publish my python source code on the internet and add links to it on my project wiki page.

Even though I did not make much progress on the HESA, it was another great day at the Makerspace.