Sunday, November 27, 2011

RAMPS Enclosure Project

After assembling the RAMPS board and testing the pololu stepper drivers with a couple of motors, I found that the stepper drivers were heating up almost to hot to touch after only mere minutes of operation. I decided that I would need to build a nice enclosure to protect the RAMPS board, and also to actively cool down the stepper drivers to attain optimal performance.

I found a scrap piece of acrylic in my junk bin and quickly set about building an enclosure. I picked up a pack of 3/16th inch bolts and drilled 5 mil holes in each of the four corners. The bolts self tapped since acrylic is a relatively soft plastic. I drilled out the center hole for the fan with a series of 1/2inch holes and secured the fan with 3M screws. The fan is directly connected into the PC power supply, so soon as the RAMPS has power, the fan begins actively cooling the electronics. I'm curious to see how well the active cooling works in an actual print situation.

Wednesday, November 16, 2011

How To: DIY PC Power Supply for RepRap

Over the last couple of days I have been cannibalizing a PC power supply to work with my (future) RepRap. I spent quite a while reading and rereading the wiki post for the DIY power supply trying to decipher what was the simplest way of putting the power supply together. I found that the wiki didn't really have any clear instructions for a simple +12V power supply, so after getting one working I decided to share how I did it. I figured out a (somewhat) elegant way of wiring that hid most of the unused wires within the power supply box. The following is a brief simplified how-to on assembling a reprap DIY power supply.

  1. Wire Strippers
  2. Wire Cutters
  3. Soldering Iron
  4. Solder 
  5. Electrical Tape
POWER SUPPLY: Any computer power supply will work that has a rating of at least 16amps on the +12V line. It should say the amperage on the side of the power supply, more than 16A is fine as the RepRap will only draw as much power as it needs.

STEP ONE: Cut all the connectors off the wires and group them by color, the four wires you are interested in are the black, yellow, green and brown ones.

STEP TWO: Select about five of each of the black (ground) and yellow (+12V) and cut them off about 2 inches outside of the power supply box.

STEP THREE: If your power supply has a brown wire (3.3V sense) solder it to an orange wire (+3.3V) and wrap it with electrical tape as shown in the image:

STEP FOUR: The green wire is a power on wire, it must be wired to a ground wire in order for the power supply to turn on. You can either wire them permanently together, similarly to step three, or run them out of the box and connect a switch to them so you can have a power switch right next to your reprap electronics.

STEP FIVE: Solder the five yellow wires together and all the black wires together in two separate groups. Then solder two black wires to the black soldered connection and two red wires to the yellow connection. After the solder connections have cooled, thoroughly wrap them in electrical tape. These wires will feed into your screw connects on your RAMPS (or similar electronic) board. I braided the all the wires including the power on wire together to keep everything clean and tidy.

STEP SIX: Cut all of the rest of the wires down to about an inch and tape them using the electrical tape in groups of similar colors (Example: all the orange together and all the black together)

FINAL TESTING: Put the power supply back together and turn it on, remember to connect the green and black wires together! If your power supply does not turn on, there may be another sense wire for the other voltage rails, look for any wires that are lighter gauge than the rest and wire them to there corresponding colors as done in step three and four.

I hope this helps!

Saturday, November 12, 2011

Weekend Project: Ruben's Tube aka Flame Tube

I know this isn't exactly related to electronics, let alone Arduinos... But I thought is was a really cool project that deserved a blog post. So here it goes.

A couple of months ago I stumbled across a video of a Rubens tube playing music and thought it was a really cool project. When I heard that we had to make a physics project for school, I couldn't pass up the opportunity to build one of these things. I followed the MAKE Flame Tube How-To and improvised a couple of steps.

I used an aluminum tube I picked up from my local surplus store, Active Surplus for twenty bucks, which was pretty reasonable compared to a two inch pipe from any hardware store. I used the regulator off of my barbecue propane tank and just screwed it into the PTC connector with some gas fitting tape. The rest of the supplies were pretty much the same as listed on the MAKE project page.
TIPS (Things I would do differently):
  1. The metal tube HEATS UP! I would suggest more than five inches of extra pipe on each end, probably at least 7 inches from the last flame hole to the beginning of the baloon. 
  2. I would suggest using some form of metal couplings rather than plastic ones because the pipe gets very hot
  3. Don't bother with pipe taps, just use pipe joint compound, its less hassle.
The results were pretty impressive, I was able to create different length sine waves using a tone generator on my iPhone. Overall, building a Ruben's tube is a pretty kick ass weekend project!


Sunday, November 6, 2011

Printed Parts Update

Just an update on the parts that I have printed so far:

Building a RepRap Prusa Mendel 3D Printer

I have been absent from the electronic scene for quite some time now, but my interested has been rekindled after some time researching 3D printers. I have decided to build one for my Grade 12 project!

My first goal was to build the printer for 450 dollars, so I began to research all the available options and their associated costs. I finally settled on a combination of parts, with the majority ordered locally. I will make a basic list of the main components and where I purchased them from:

Electronics - RAMPS board on Arduino Mega Mega
Motors - Wantai 42BTGHW811 bipolar hybrid stepper motors
Stepper Drivers - Pololu A4988 stepper Drivers
Vitamins - Complete structure kit
Extruder - Complete Wades Extruder kit

So far I have received the Arduino Mega and the RAMPS board, which I assembled. If you aren't comfortable with SMT soldering, I would suggest going with the SMT already Soldered option.

I went to the open night at the Toronto Hackerspace and found out that they had a working makerbot which they are generously letting me print my parts off of. So far I have printed 3/4 of the parts over the course of a couple weekends. Hopefully by next week I will have the Mixshop order and all the parts printed and will be able to begin assembly!

Unpopulated RAMPS
Finished RAMPS Board