New Maker Podcast

I like to listen to podcasts while in the car. Just this weekend I found a new Maker - oriented podcast called, the "Gadget Makers Blog". The description on the blog's website says, "Articles, tutorials & how-tos on electronics, Arduino, 3d printing, and more."

There are only two episodes so far. The first was a general discussion about the author's recent Kickstarter product named Recap as well as some general electronics talk.

The second episode talks about how the author bought some fake chips from Ali Baba, the Chinese Amazon.com. I found this episode to be pretty interesting. I have heard of Ali Baba's but never bought anything from them. I don't think I will after hearing about this.

I'm definitely going to keep listening to this podcast. If you know of any other interesting Maker or novice electronics podcasts please post a comment.

New Water Detection Circuit

I was showing my nephew my Home Environmental Sensor Array over the Thanksgiving holiday.  We tested it at his house with his city water.  It took about a minute to detect the current but it eventually did.

My nephew did some research and came up with a potentially better and simpler circuit.  It basically sends power out through on of the Raspberry Pi's GPIO ports and looks for a signal on another port.  There is a resistor on the input side that connects to ground.  This stops the pi from getting false readings.

When we tested it out, the circuit never gave a false reading when connected to the resistor.  It also detected the current in his water immediately every time.  I'll have to solder up another circuit board and test it out at the Makerspace.

I don't understand why the circuit works to block transient current.  Maybe someday...

Here is the circuit that I documented using Digikey's Schemeit.

Fun With a New Arduino

I was visiting my Mom and sister and nephew over the Thanksgiving holiday.  My nephew is, like me, interested in electronics and microcontrollers.  We spent a lot of time just goofing around with different projects.  It was a great couple of days.

There is a neat store near his house called Gateway Electronics.  They have pretty much everything you could want for electronic projects for good prices (and free Twizzlers).  I bought an Arduino Uno, a continuous operation servo, and a couple of potentiometers.  My nephew bought the DFRobot Arduino LCD keypad shield for his Arduino.  We spent the rest of the day trying to get the Arduinos working with LCD displays and the servo.

Adafruit has a web page that explains how to connect an Arduino to an LCD.  The LCD in the example was a 16x2 LCD.  I had an LCD display from the Milwaukee Makerspace.  It looks like most LCDs are the same.  They have 14 or 16 pins.  Pin one is ground.  Pin two is power in.  Pin three is to control contrast.  Pins 15 and 16 control the backlight, if the LCD has that feature.  Pins 4 through 14 are to send data to the LCD.  Check out the Adafruit web page for more details.

The Arduino IDE comes with several example programs for displaying on an LCD.  Plus, there is a built-in library called LiquidCrystal that makes it very easy to work with LCDs.  The Adafruit page does a good job explaining the basics for first-time users like me.

Our first try at connecting the Arduino to the LCD was a bit flaky.  The display would go a bit crazy after the first boot-up.  If we wiggled the cables, the display would change.  We replaced all of the cables with different ones and the LCD worked perfectly.

Various web pages say that a potentiometer is needed to control the contrast.  You can see it in the picture above next to the right-hand corner of the LCD.  It basically needs power and ground on the outside pins.  The middle pin connects to the contrast pin on the LCD.

My nephew hooked his DFRobot LCD shield to his Arduino.  Their web page has some sample code.  He downloaded the code to the Arduino and the board worked great -- at first.  After about 30 seconds, the display started getting flaky.  Tapping on the screen would settle it momentarily.  Everything works functionally, but the display is not stable.  Looks like he will have to exchange it for a better one.

Next, I hooked the servo to the Arduino.  I found an Arduino sketch to control the servo with pulse width modulation.  It basically lets you press keys on the computer keyboard to speed up and slow down the servo.  I played around with the minimum and maximum settings and was able to get the servo to go both clockwise and counter clockwise.  I also added the LCD code to the sketch to display the pulse width setting on the screen.  Nice!

The Arduino IDE comes with a library for the servo called the Servo Library.  I did not play with the Library much but I was able to get it to go clockwise, counterclockwise, and stop.  The library did not control the time, nor the speed.  Maybe it will, but I could not get it to work that way.

In the picture to the right, you can see the Arduino in the front, the LCD in the middle, and the servo in the rear.  I would like to use the Servo to control the automated pet food dispenser.  In theory, I could connect the Arduino to the servo and plug the power for the Arduino to a timer that will turn it on once or twice a day for five minutes.  The program I wrote moves the augur counter-clockwise for about 1 second.  Then, it rotates clockwise for 2 seconds.  According to the Instructable about the dispenser, this will keep the augur from jamming on food pieces.  One weird thing is that the program works great when the Arduino is connected to the PC but not when it is connected to a USB power converter.

Here is the code to control the servo.

#include <server.h>

Servo augur; 

void setup() 
{ 
} 

void loop()
{ 
  // Make the servo turn clockwise then counter 
  // Set up the servo 
  augur.attach(9); 

  // Spin counter clockwise 
  augur.write(-180); 
  delay(1000); 

  // Spin clockwise 
  augur.write(180); 
  delay(2000); 

  augur.detach(); 
  delay(500); 
}

Found Stuff to 3D Print on Thingiverse

I was browsing through the entries on Thingiverse and found some things to 3D print at the Milwaukee Makerspace when I have time.

First of all, I found this cool looking wobbly chess set and board.  I would like to print a copy to either give away or raffle off at the Star of Bethlehem Open chess tournament that I am organizing along with the International Academy of Chess on January 25, 2014.  I'm not really sure what I am going to do because the person who uploaded this thing says it took 60 hours to print.  That will be a challenge for me since I only have about 4-5 hours per week to work on this and the tournament starts in about eight weeks.

Another Thing I found is a case for an LCD screen.  This would come in handy for the enclosure of my Home Environmental Sensor Array.  In phase two or three of the HESA project, I want to add an LCD display so the computer (probably a Beaglebone) will display current status information.

Finally, I added this DIY Magnetic Stirrer to my collection of things to make.  This looks interesting to me because it will let me use the 3D printer, which is always fun, and because it re-uses an old computer fan, keeping it out of a landfill.  I don't do chemistry experiments that require a stirrer but maybe someone at the Makerspace can use it.

Review of Make: Zero to Maker book

I recently read a book named Zero to Maker: Learn (Just Enough) to make (Just About) Anything by David Lang.  Here is my review.

Zero to Maker is about one man's journey to go from knowing next to nothing about making stuff to becoming a full-fledged Maker.  Along the way, he explains all aspects of the burgeoning Maker movement, from how to get involved in making (I recommend joining the Milwaukee Makerspace if you live in the area) to "going pro" with your own business.  Lang explains the software and tools commonly used by Makers -- Instructables, Meetup, Sketchup, 3D printers, welding, etc.  The book is full of real-life stories of Makers, inventors, and entrepreneurs and has dozens of links to web pages of Makers, tools (both hardware and software), and how-tos.  The final chapters of the book cover topics for entrepreneurs like building a team, raising money, and protecting your idea.

Lang got into the Maker movement after being let go from his Marketing job at a start-up company.  Rather than find another job in his field, he decided to parlay his writing skills into a 30 day adventure into making.  Lang partnered with Eric Stackpole to develop a DIY, open source, underwater vehicle (openrov.com).  Working on the open ROV project forced Lang to learn many new skills including electronics, robotics, microcontrollers, CNC machining, among others.

Lang also wrote a blog about his experiences for Make:  To get material for the blog, and eventually for the book, Lang interviewed people in the Maker movement, visited hackerspaces and tool lending libraries, and joined the TechShop in San Francisco.  His varied experiences make for interesting reading.

I recommend this book to people who want to learn more about the maker movement, and new makers.  Experienced makers will also find the stories interesting but may not learn a lot of new things about the tools used.

I also made an outline for the book on Google Docs.  Feel free to check it out and make comments to enhance it.

Enclosure for HESA

Now that I finished the circuit board to detect water for my Home Environmental Sensor Array, I started working on the enclosure.  (I was hoping to use a power supply from an old computer but it is too small.)  I was at the Milwaukee Makerspace today and found a box that would make a good enclosure.  One problem is that it does not have a front piece.

Jim, another member at the 'space, had an idea to make a front piece from acrylic.  We quickly cut the piece on a circular saw.  Then, we cut a notch in the top where the LED is.  The piece slides under the top lip.  Finally, we drilled holes on the sides to attach the acrylic to the box.  Thanks for all the help, Jim.

The acrylic piece has some blue cellophane on it to protect the acrylic.  I will remove that later after I have everything installed.

The next step will be to cut a piece of wood for the main part of the enclosure.  Maybe I will use the CNC router just for fun.  I will attach the wood to the enclosure, then attach components like the Powerswitch Tail to the wood.  This enclosure should be big enough for future enhancements as well.

 Another great day at the Makerspace.

Second Tardis Printed and Painted

I was at the Milwaukee Makerspace this afternoon working on several projects.  One thing I was able to do is finish printing all of the pieces of my second Tardis.  I printed the battery holder and lamp cover with the red filament.  Then, I printed the windows and the lamp with the glow-in-the-dark filament.

Next, I painted all of the pieces on both sides in navy blue spray paint in the 'spaces paint room.  At first, I was concerned that the blue would not cover the filament colors but they turned out good.

The next step is to find LEDs and the other electrical components to install the lighting inside the Tardis.  The guy who designed this sells a kit for $12 but I'm going to try to scrounge up the parts myself.

Circuit Board Finished and Working

I spent the afternoon at the Milwaukee Makerspace today and finished my hand soldered circuit board to detect water for the Home Environmental Sensor Array.  I started it last week but only got about halfway done.  Today, I soldered the second half of the detection circuit, and added two screw terminals.

One pin on the first screw terminal connects to a pin that constantly puts out 5v of power on the raspberry pi.  The other terminal goes to a ground pin.  That terminal will be used to power the fan on the power supply box.

The other screw terminal connects to pins 7 and 9 on the rapsberry pi.  Pin 7 will output 3v of power to turn on the PowerSwitch Tail.  Pin 9 is ground.

It probably took about three hours to get everything soldered.  I took my time testing each connection and looking for shorts with the multimeter to make sure I did not do anything wrong.

I plugged the Raspberry pi's ribbon cable to the pin headers on the breadboard and fired up my HESA program.  It worked perfectly (more-or-less).  The fan spins, the PowerSwitch tail has power, the program alternately sends power out one of the four circuits, and it detects power coming back in when a circuit is closed.  The only thing that did not work is that it did not detect current when using water from the Makerspace tap.  However, that did not work last time I tried it but the circuit did work with New Berlin water from my well.  So, I'm hopeful that the circuit will work at home as well.  If not, or if I want something more reliable, I can replace the test leads with a float that closes the circuit when the water gets too high.

Next step: Build an enclosure.

Started Making Circuit Board for HESA

Fridays are my regular time to work on projects at the Milwaukee Makerspace.  This Friday past I tried making progress on my Home Environmental Sensor Array.  Specifically, I worked on the circuit board.

There are many different ways to make a circuit board.  I am going to try three of the methods that I can do at the Makerspace:

1. hand soldering components onto a breadboard, 
2. using the CNC Engraver to grind away copper on a board leaving only the traces and drilling the holes, 
3. using the laser cutter and acid to remove copper around the traces I want for the circuit.

PCB with Laser Cutter Process

First, some background on making a circuit board using the laser printer.  (I don't fully understand the complete process but here is what I know.)  Start with a copper plate that has copper on only one side. Cut out a piece of the copper plate that is big enough for the circuit board.  Cover the entire copper side with black spray paint.  (Any color will do but black is the most satisfying color.)  Put the piece on the laser cutter and print the pattern from DipTrace.  The laser cutter will burn off the black spray paint, revealing the copper. In the picture to the right, the black areas are where the laser cutter will remove the black paint. The revealed copper is where the holes will be drilled and also in between the circuit traces.  The next step is to use acid to remove the exposed copper.  The remaining copper is for the circuit.  After laser cutting, holes need to be drilled for mounting the components and to affix the PCB to the project box.  The final step would be to add the components to the PCB.

Designing with DipTrace

Before using either the CNC Engraver or the laser cutter, I needed to design the PCB in DipTrace.  I had it mostly done last time.  Tom G. helped me get the drawing ready to print on the laser cutter.

There are some things to know when designing a PCB in DipTrace (or probably any design tool).  The components should be put on the top layer of the drawing while the traces and holes should go on the bottom layer.  (The bottom layer is where the copper is.)  Also, Tom had me make the holes smaller and the circles around the pads bigger.  He also suggested that the trace width be a bit bigger.  All of this will make working with the PCB a bit easier.

One other designing hint is to put some mirrored text on the bottom layer.  This helps to know that you are looking at the right side when you do the print.  The standard is to put the letters RR on the bottom.  I already had my name there so we kept that and just reversed it.

Printout sample on paper
and painted copper

After getting the entire circuit done, we added a "copper pour" to tell the printer not to remove anything but the traces and holes.  In DipTrace, this is done by choosing Objects, Place Copper Pour.  Then, click on three of the corners and press Enter when the mouse is on the fourth corner.  A menu will appear with some options.  Make sure the "current state" field says "poured" and click OK. 

The final thing to mention is about printing.  When doing the print in DipTrace, make sure to click the Mirror and Negative boxes.  I think you would not check the Negative box when printing to the Engraver.

Using the Laser Cutter

I have not been trained to use the laser cutter so I will have to try printing the design some other time when there is someone who can help me.

Using the Engraver

I wanted to make a PCB using the CNC Engraver but it is in pieces right now so I could not use it.  I would like to use the Engraver because it will also drill the holes in the board.

Using a Breadboard

I was able to make part of the circuit on a breadboard.  I started by soldering a terminal strip in the middle of the board.  A ribbon cable will connect the raspberry pi to the terminal strip.  I used a multimeter to see if any of the pins were shorting each other out.  I did find two and had to remove some solder.  Next, I added resistors and sensor wires on each side of the strip.  I used the wires from the resistor to connect the components together.  The odd side circuit worked when I tested it with the multimeter.  

The soldering is not done yet.  It looks terrible and there are probably some shorts that I will have to fix.  Overall, it was fun so far and will be satisfying if it actually works without frying my raspberry pi.

Front side

Back side

Second Tardis is Mostly Printed

I am printing a second Tardis on the 3D printer at the Milwaukee Makerspace.  This time, I am making it more solid.  Plus, I am going to install a small circuit to power LEDs and light up the top.

Yesternight I printed the open base piece, and both top pieces.  The only pieces left to print are the lamp pieces and the battery piece.  I should be able to print the rest of the pieces in one day provided that the printer works with no problems.  Lately, it has been working great!

The picture shown here has the pieces printed so far except the ring top piece.  They are different colors because I used different colors of filament.  All of the pieces will be spray painted navy blue later.

Fixed Python Environment Variable Problem

I spent some time working on the python code for the HESA program tonight.  I want to have a sub-folder called modules to store re-usable code.  That way, I can have program code in its own folder without duplicating functions.

Up until now, when I tried to import code from the modules folder, it would not find the file.  I finally figured out how to change the path environment variable so the program finds the module files.

Here is the code.

# Load libraries 
import sys 
sys.path.append('/home/pi/python/modules') 

After this the import command will look for files in the current folder and the modules folder.

HESA Circuit Does Work in Water

When I tested the water detection circuit for my Home Environmental Sensor Array at the Makerspace yesterday, I used distilled water from a water bottle.  That is probably why the pi did not detect a current.

I setup the HESA at home and tried some water from our well.  At first, the HESA did not detect any electricity.  I left the leads in the water for a few minutes and it suddenly worked!  The HESA detected the current and shut off the light I connected to the outlet.  After that, the circuit always detected the current.  Maybe the water needed to get a bit electrified first.

Next, I got some water from the crock that I eventually want to put the sensor in.  That water should have more saline and iron in it making it a bit more conductive.  The HESA took a minute to work in that water as well but after a few minutes, the circuit worked and very consistently.

So, I'm feeling better that the circuit will actually work as designed.

Now, I can focus on the PCB and enclosure.

Started Circuit Design to Etch a Circuit

The Milwaukee Makerspace has a CNC Engraver that can be used to make circuit boards.  The wiki for the engraver says that there is software called DipTrace on the computer.  I assume that this software is used to create the PCB design.

I downloaded the software and installed it on my Linux laptop.  The program is made for Windows but my Linux OS automatically launched Wine to install the program.  Cool!

I spent about an hour designing a simple circuit on the PCB.  I was able to figure it out without reading a manual.  If I make it to the Makerspace this week, there might be someone there who can help me take the next steps and use the Engraver.

HESA Circuit Does Not Work in Water

My wife and kids were all gone for the afternoon so I took the opportunity to head back to the Makerspace and work on the Home Environmental Sensor Array.

First of all, I spent a few hours working on the power supply enclosure.  I redid the wiring slightly to power up both the PowerSwitch Tail relay and the Raspberry PI.  The picture on the left below shows the PSU enclosure rewired.   There are some bare wires that will be wired in to the PST.  There are also wires with connectors on the end.  They will plug in to a USB power plug for the raspberry pi.  The red and black wires connect to the fan.  The pi will power that.  

The middle picture shows the PowerSwitch Tail wired in to the box.  

The picture on the right shows the whole project wired up and working.  You can see the wires plugged in to the USB power converter for the pi.

One problem I can see is that the PSU is not going to be big enough for this project.  I am thinking that I would like to try cutting apart two PSUs and combining them into one big project box.  I talked to Dan at the Makerspace and he thinks it should be doable.  I would use a cut-off saw to cut one end off of each PSU.  Then, I would use the TIG welder to connect them together.  Should be a fun project to learn to use some metal working tools.

Another problem I had is that the circuit does NOT work to detect electricity in water.  It works great when a wire is used to complete the circuit.  However, when I put the end of the wire in a small cup of water, the pi does not detect a current coming in.

Someone told me that I need a potentiometer in the circuit so I can variably adjust the resistance.  I'll have to research this some more.

Finally, I have started thinking about how to make a circuit board for this project.  There are basically two options.  First, I could solder all the components and connections on a circuit board like the one to the right.  Or, I could make my own circuit board using the Makerspace's CNC Engraver.  The Engraver may be more work but I would be learning a new skill, a new machine, and possibly have a way to make more of the circuit board quickly.  I might try both methods because I can.

Started Second Tardis

I started 3D printing a second Tardis. Now that I know what I am doing on the 3D printer at the Makerspace, they are coming out much better.  This time, I am printing the sides with 90% infill to make them stronger.  

As you can see from the picture, the blue filament ran out after the first print so I switched to green.  They will all get spray painted navy blue when all the pieces are printed.

I hope to put electrical wiring in this Tardis to make it light up.

By the way, these three pieces took a bit over nine hours to print.

HESA Works!

I was working on the Home Environmental Sensor Array at the Milwaukee Makerspace today.  (I took the day off so I was able to make some good progress.)

I had an idea to use an old computer power supply as a project box for the HESA.  It makes sense because I need an enclosure to put the parts in, 120v power, an on/off switch, and a fan.  The power supply box has all of that.  I hope to install all of the parts inside the power supply box and then mount it to my wall.  This includes the PowerSwitch Tail relay, the raspberry pi, and the circuit board.

After taking of the electrical components out of the power supply, I wanted a rectangular piece of wood to attach to the box where the old circuit board was.  This would allow me to attach parts to the wood and not the metal.  I also wanted to use the CNC router to cut the wood just so I could use the router again.  I had to design my own DWG file.  The tool I used to design the wood piece was LibreCAD.  LibreCAD is free and runs on Linux.

The wood piece is a simple rectangle with four holes to attach it to the power supply.  I spent about 2 1/2 hours designing the piece and then cutting it with the CNC router.  It takes a lot of time to measure everything precisely and then design it in the CAD software.  It does not help that I have not used LibreCAD and have to try and retry everything many times.

All that being said, the results were perfect.  The nice thing is that I can re-cut as many of these as I want with the exact same specifications.  In fact, I did cut six more before I left just because I could.

After cutting the wood and mounting it in the power supply, I also installed the PowerSwitch tail in the power supply box.  When I turn the switch on for the power supply, the PST has power as well.  Cool!  Next, I need to figure out how to wire in my raspberry pi to power as well.

The fan that came with the power supply did not work so I replaced it with a different one from the parts rack at the Makerspace.  The fan says it requires 12v input but it will work down to 3v.  My raspberry pi has a 5v output so it does power the fan, albeit a bit slower than it could run.

Now that the enclosure is working a bit I started testing out the new circuit.  First, I wired up the A and B circuits.  Each circuit has two outputs and one input.  One of the outputs sends a signal through a 1k resistor and the other sends a signal through a 100k resistor (not at the same time).  The way it work is like this.  The program on the raspberry pi sends out a signal on circuit A's 1k section.  The input on circuit B looks for a signal.  Then, the pi turns off the first signal and sends another on circuit A's 100k section.  If circuit B does not see that signal, the pi shuts off the signal and tries the same tests sending on circuit B and listening on circuit A.

For whatever reason, this circuit design works perfectly.  The pi always detects a signal when it is sent over the part with the 1k resistor.  I never got any false readings.  I think the problem is solved.

Here is a link to the circuit schematic.  I made it in Digikey's free SchemeIt on-line tool.  By the way, I have tried a few of schematic designers.  Most of them are either not free or too complicated.  I just want to make simple schematics for electrical circuits.  Circuit Lab was nice but is no longer free.  I installed the Electric VLSI Design System on my Linux computer but it is too complex.  SchemeIt was pretty easy to use, and allowed me to easily create my schematic.  I can share the link on the internet and even save it to PDF if I want.  For now, I will stick with SchemeIt.

I also made some videos of the HESA in action that I will upload to YouTube and post a link to.

Another great day at the Makerspace.

Pitcher Holder "Fixed"

The pitcher holder piece that I 3D printed for the automated pet food dispenser does not fit correctly on to the PVC T.  The inside diameter of the pitcher piece is just a bit too small.

I used a drill press and various tools at the Milwaukee Makerspace to rough out a bit of the inside diameter of the part.  I tried different tools (see picture) starting with a little Dremel sander (not pictured), then a 1/4" drill bit, a bigger gear-looking bit, and finally, a wire brush.  The sander and wire brush both worked but are incredibly slow.  The drill bit did not work at all.  The gear thing was too coarse.  It kept gouging out parts of the plastic.

Eventually, I did shave off enough plastic to squeeze the holder onto the PVC.  Unfortunately, I shaved off enough plastic to get to the inlay and crack the piece.  You can see the crack in the picture of the piece.

I will see what Tim thinks but we will probably push on and try to finish assembly with what we have as a beta.  Then, I can re-measure everything and try to re-size and re-print the auger and pitcher holder to fit the PVC dimensions.

I think that will be after I get the HESA project done.

Pet Feeder Assembly Started

Tim and I started to assemble the automated pet feeder parts.

Actually, before we started, I went to Home Depot and bought a 2" circular wire brush that can be inserted into a drill.  Tim and I spent some time using it to smooth out the inside of the PVC T.  After many minutes with the drill, most of the raised part is gone but there were still some higher spots.

We then tried shaving off some of the other auger piece to make the circumference smaller.  That did not turn out so well.  During the process, a bigger part of one edge was cut off.  Then, one of the parts near one end broke off.  Even though it seemed like we cut off quite a bit of the auger, it still sticks a bit in some spots.

We did start assembling the pieces to see how it looks and to feel like we are making progress.  See the pictures.  A pitcher to hold the dog food would go on top of the blue part (that does not fit on the PVC either).  The servo would be attached to the white piece that is attached to the wood support.

I think that I will continue to try smoothing out the inside of the T.  Also, I have an extra auger that was not printed perfectly.  I think I will use that one instead of the broken one.  Hopefully, it will fit in the T if I can get it smoothed down.

Another idea would be to use a plunger instead of an auger.  Maybe that would be more reliable.  I'll have to see if I can find a device to push a cylinder through the PVC.

Finally, now that I've got some experience with this, I would do a few things differently.  First, I would purchase the PVC T and figure out the servo and controller before starting to make anything.  That way, I could measure the PVC and possibly adjust some of the prints and cuts.  Also, knowing what the servo would look like would help to know what kind of end piece would be needed to attach the servo to the wood support.

PVC T for Pet Food Dispenser

Over the weekend, I bought a 2" PVC T and the hardware to assemble the pet food dispenser.  When I got home, I tried inserting the PVC into the wood supports that I cut on Friday.  The hole was just a bit too small.  My theory is that we should have made the cut for the hole right on the line instead of on the inside of the line.

Next, I tried putting the augur in the T.  It went in the first few inches just fine.  Then, it hit the raised part that is made to step the PVC that is inserted into the T.  Doh!  The augur was sized for a 2" diameter but the inside of the PVC is about 1 3/4" with the raised part.  Strike two.

First, I went to Home Depot and bought a different PVC T.  This one still had a raised part inside but it was about half as thick as the other T.  I was hoping it would be easier to make it work.

Then, Tim and I stopped off at the Makerspace to fix the two problems.  We put an abrasive disc Dremel part into a drill press and used that to make the holes on the wood bigger.  It took a few passes to get it right.  Now, the PVC T fits snugly into the wood supports.

Once that was done, we turned our attention to the augur.  At first, we tried getting rid of the raised part on the inside of the T.  We used a hand file and spent a good bit of time with that.  It did make some difference but not enough.  One problem is that the file was flat and the inside of the PVC is round so there was not enough surface area contact.

Finally, we used a band sander to remove a layer off of one of the auger halfs.  That was very ugly but it seemed to work.  I only brought one auger half so we could not finish the job.

After we left, I thought that we should have used a circular wire brush attachment for a drill.  I did not see one at the space.  Maybe I will go to Home Depot and buy one and then use it to smooth out the inside of the T.  I might also have to re-print the augur parts if they will then fit on the inside of the T.

I will chalk this up to a learning experience.

First CNC Router Cut

I spent the evening at the Milwaukee Makerspace.  Tonight I learned how to use the CNC router.  Brant, the President of the 'space spent over an hour training me.  (Thanks Brant!)

I used the CNC router to cut the wood support pieces for the automated pet food dispenser.  The very first thing you need to cut something on a CNC router is a drawing.  The thing you want to make is designed in a 2D software application like SolidWorks, AutoCAD, or Google Sketch.  The application needs to output the results in STL format.  Fortunately, I was able to get the STL file for the wood supports from the Instructables page.

The next step is to load the STL file into a program called CamBam.  CamBam takes CAD drawings and converts them into a script (called G Code) that the CNC software can understand.  Brant and I played around a bit with the settings.  At first, CamBam was confused about how to cut the outside of the piece.  We had to combine all of the individual line segments that made up the outer edge into one long line to make it easier to follow.  Brant spent a lot of time showing me all of the settings in the software.  We got everything working so the machine would cut the hole in the middle, make small indentations for the screw holes, and cut out the entire piece.  The last step was to save all of the commands required to cut the piece as a G Code file.

The G Code text file was loaded into a program called Mach3.  Mach3 is the software that actually controls the CNC router.  It processes the G Code line by line, sends signals to the CNC router and processes the results.  We also had a small amount of setup to do in Mach3.  Basically, we had to center the router in the correct position and height to do the cut completely within the piece of wood.  That only took a few minutes and we were underway.

We programmed the CNC machine to make three passes of .25 inches each.  In hindsight, maybe it should have made more passes.  That might have kept the wood from getting torn up.  The total cut time was only about three minutes per piece.  After the first cut was done, we moved the bed, re-zeroed the router, and cut the second piece.

Here is a link to a short (and somewhat boring) video showing the first cut on the CNC router.  As you will see, we had to hold down the piece when it made the indentations for the small holes.  We fixed that on the second cut by adding more holding tabs and also cut the outline of the entire piece last.

After cutting both pieces, I sanded them and then drilled the small holes for the screws.

I have finished making all of the pieces for the dispenser.  Now, Tim and I need to put it together.

Another great day at the Makerspace.