Formula SAE Pedal Box

During the last competition our school's team lost points for using an off the shelf pedal box instead of designing and building our own.  I designed one for this year's competition but unfortunately it isn't being built because of budget constraints but the design and stress analysis are done and I'm pretty proud of it so I'll post it here anyway.

Digital Space Heater Temprature Control

A problem common to most electric space heaters on the market is that the thermostat that controls the heater is enclosed within the case of the heater itself.  As the heater runs the case heats up and the thermostat shuts it back off again.  This means that the thermostat reading is only loosely related to the actual temperature of the room, the thermostat mostly just sets the duty cycle for the heater.

My room gets fairly cold at night so during the winter I run a space heater but because of the lack of sensitivity of space heater thermostats my room can get colder as the temperature outside get colder and then uncomfortable hot in the morning when the sun comes through the window.

Using an Arduino Uno, a small servo and two 3D printed components I retrofitted a digital thermostat onto my old space heater so it could more accurately control the temperature in my room.

The Arduino has a temperature sensor hooked up to one of the analog pins in the board to read the temperature of the room.  I can then set a temperature for the room and the Arduino switches the space heater on and off via a servo connected to a dial on the heater.  I considered using a relay controlled by the Arduino to switch the heater on and off but I didn't want start tampering with the wires inside the heater and risk creating a fire hazard.

I used 3D printed components to couple the servo arm to the shaft that the dial was on and another component, bolted to the heater body, to hold the base of the servo in place.  The design was very simple and only took about 2 hours from measurements to having a finished model ready to be printed.


This setup works perfectly and my room is always at a stable temperature.  I plan on soldering the whole project onto a prototype board and flashing an Atmega 328 so I can make this installation permanent since it works so well.

Cell Phone Windshield Mount

I had an old in vehicle GPS system that needed to be retired and at this point my phone is a better GPS receiver any way.  I decided to design and print an enclosure for it that could use my old GPS mount to secure it to the windshield.

        

 The design goals for the enclosure include: 

• It holds the phone securely and rattle free while still allowing the phone to be removed easily. 

• It should not cause an unnecessary obstruction of the view of the road or the screen on the phone.   
• It should be mostly 3D printable while any printed parts should be easy to fabricate or buy locally.  
• It should use as little materials as possible without sacrificing strength, durability, or other previously mentioned criteria.  
• It must interface with my existing mount for my GPS.
  

                I took careful measurements of my phone’s exterior dimensions, screen dimensions, and USB port location using standard digital calipers and used those dimensions to create an enclosure for it in Pro/Engineer.  The end result is an enclosure that holds the phone securely but still slides in and out easily without difficulty.  I had considered adding some sort of latching system to secure the phone in the enclosure but instead chose to simply use a USB cable to prevent the phone from sliding out since the phone will always be hooked up to a charger when using it for navigation.  Removing the cable allows the phone to slide out the right side of the enclosure.

                The design had to be printed in two parts and glued together due to the limitations of the 3D printing process. I included holes in the 4 corners of both pieces into which stainless steel pins were inserted to both locate the two pieces and provide added shear strength to the joint. These pins were the only non-printed parts. 

Wood Chipper Blade Jig

I used to work at a construction equipment rental shop. We would send out blades from wood chippers to be sharpened in large batches.  When they came back they were all different lengths due to different wear on each one and for the chipper to cut wood efficiently the set of 4 blades had to be very close to the same length.  The previous method of using ones fingers to line up the bolt holes of a stack of 4 blades then check to see if the cutting edges line up with a ruler was not very accurate or quick.  I decided to make a jig to align the blades that included a small vertical slider to check the alignment of the cutting edge.

After measuring the blade’s dimensions with calipers and printing out a small piece to check to make sure I got the dimensions right I printed out the base with no issues.  The dovetail joint for the sliders, however, was very difficult.  For some reason the dimensions of the dovetail joint on the slider were different than the dimensions I specified in the CAD program so I had to resort to trial and error to get the dimensions right.  I suspect it was caused by the G-code generator rather than the printer since other parts of this project were being printed with accurate dimensions.

Purpose

I started this blog to document the objects that I design and build and to hopefully inspire others to use or adapt my work for their own purpose.  I have spent most of my summer vacation building, calibrating, and tuning my 3D printer in my spare time after work and I can now print out my own designs that I model in CAD software.  This blog is not about 3D printing or 3D printers and I hope to include other processes for creating objects.  I have limited experience in metal working but would like to include some metal working projects in this blog if I have the opportunity.