PI Time

DIY Auto Cat Feeder

When the Raspberry Pi came out a few years ago I picked one up in the hopes to create some home automation projects. As with many of my projects it never really eventuated as life and work took over as they tend to do. Well this year I attended the Adelaide show with my wife and made a visit to the science and tech centre pavilion. Looking over some of the cool projects the high school and primary school kids had put together rekindled my interest in electronics and specially the Pi.
I spent the next few weeks looking through Raspberry Pi projects but couldn’t really find a particular project that involved the pi and something I do every day that could be automated. That was until I came across this project. http://drstrangelove.net/2013/12/raspberry-pi-power-cat-feeder-updates/
We have had two cats for some years now and have tried various manual auto type feeders but found one of our cats in particular would eat its weight in food. Not naming anyone Charlie!!!
Looking over this project, It seemed to solve two of my problems that we sometimes face if we go away over night for an example.
1) Feeding that Cats
2) Ensuring they don’t eat too much.
Enter the DIY Cat Feeder Project.
I first began by thinking of what i would like my feeder to do. I wanted some sort of indicator to let me know it was about to dispense food and also some sort of alert tune. I started by creating a basic prototype on a bread board with two LED’s and a piezo buzzer and wired them up to my GPIO ports on the PI
breadboard

Ringed Gidgee Scales

I purchased my scales from The Timber Joint and went ahead with Ringed Gidgee.
Here is some info about the unique hardwood sourced from The Timber Joint Website
“Ringed Gidgee is a unique and rare Australian hardwood. This difficult to find timber is highly sought after by knife makers. It is known for its depth of colour, beautiful figure and extreme hardness. Gidgee is classified as the 3rd hardest wood in the world, according to The Wood Data Base, making it an excellent knife making timber.”
ringedgidgee

Heat Treatment

With my blade nicely sanded it is time for heat treatment to strengthen the blade. I had a look a various DIY heat treatment options such as this great tutorial from Gough Custom. Heat Treatment
Seeing as it was my first attempt I decided to send my blade to Hills Heat Treatment in Victoria. After a couple of weeks it returned treated and ready to go.
Droppointheattreat
I now have to clean it up and attach the scales. I’m looking at using an Australian grown timber called Ringed Gidgee. More on that to come soon!

Now the hard work begins

Using the filing technique in the tutorial mentioned in a previous post I began the tedious process of filing a bevel on my drop point knife. This requires plenty of patience and a lot of elbow grease. I needed to be very precise with the filing and ensured I left a 1mm thick edge on the knife to ensure the blade did not warp during heat treatment. Once I was happy with the bevel I gave everything a sand with 120 grit to remove the deep scratches from the file. I thought the filing was tedious but it has nothing on hand sanding.
droppoint120grit

Sketching the Design and taking shape

Whilst waiting for my steel to arrive I spent some time researching simple drop point designs. I decided on a drop point as I find they are more suitable for hunting and general camp work as they have a stronger point than a clip point so are less susceptible to damage.
Through my research I came across a great blog with plenty of templates. DC Knives
Once my steel arrived I sketched my chosen template onto my bar of 15n20 steel.
KnifeSketched
With my template applied to the stock I used an angle grinder with cutting disk to remove the excess stock around the template to speed up the grinding / shaping process. Once i had cut down the stock to as close as the template as possible, i finished shaping the template by attaching a grinding disk and carefully grinding away at the stock until I was close to my template lines. I then neatened it up with my file.
kniferoughshape

Building a Knife Filing Jig

After watching many YouTube videos and visiting various forums I decided to give knife making a go. The first step was to work out what tools I needed to make a basic knife. After doing some searching I found a simple drop point knife can be made with nothing but some appropriate steel and a flat bastard file. I sourced my steel (15n20) from a local supplier and got to work sorting out what tools I required to get started.
Through my research I found a awesome tutorial on building a knife filing jig to assist with cutting in the bevel and shaping the blade. I set off to bunnings with a list of gear to get myself started. I purchased the gear required and quickly got to work assembling my knife filing jig as per this great tutorial from Gough Custom.
Knife Filing Jig
Here is the end product. A bit rough but should do the job.
Knife Jig