Apr 21

Dissolve a Tap Broken in MakerSlide

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About 10 minutes into my Shapeoko I hit my first snag. One of the steps in assembling the Shapeoko is to tap the maker slide in order to create threads where a screw can be put into. While tapping my first piece of MakerSlide I snapped the tap off inside the MakerSlide with almost nothing sticking out the end. I tried using pliers to get it out but the piece was lodged in there pretty good and I could not remove it. I did some research online and found I was not the first to have this problem. I found several people talking about dissolving the tap while leaving the aluminum intact. Thankfully it worked and I’m back on track. Here is how I did it.

Supplies

  • Aluminum, glass or Pyrex container
  • Hotplate
  • Alum (I used aluminum sulfate from a local pool supply store)
  • Wooden or plastic stirrer
  • straw or pipet

How It’s Done

  1. Boil water and put it in your container (enough to cover the tap in the MakerSlide)
  2. Put your container on the hotplate and turn it on (I used an old coffee maker)
  3. Add alum to the water and stir in until no more will dissolve
  4. Put the end of the MakerSlide with the tap into the alum solution
  5. Use the straw or pipet to drop some alum solution into the top of the hole the tap is in (this helps to dissolve the tap from both ends)
  6. At this point you should start to see little bubbles coming off of the tap
  7. It took about 8 hours for the tap to dissolve enough that it practically fell out.
  8. The end of the MakerSlide that was in the alum solution will be a little discolored. Just wipe it with some WD40 to remove the white residue

How to Prevent This from Happening to You

I made 2 major mistakes: I didn’t use lubrication and I was too aggressive with the tap. Please learn from my mistakes. Many people online recommend cutting oil but once I got a new tap I ended up using WD40 and it worked great. You should also turn the tap slowly. If you feel any resistance back off on the tap a quarter or half turn and try again.

Apr 15

My Shapeoko Build

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In my last post I wrote about creating a BlinkM module on a breadboardshapeoko and wanted to create a more finished project based on that design. I looked into etching a PCB and after much research decided to use the magazine laser toner transfer process followed by the Hydrochloric Acid (H2O2/HCl) etchant. I bought all the supplies and had nothing but trouble with it. Then I remembered a Hack-a-Day post from last year with a video of a CNC milling a PCB. This seemed like such a cool solution to my problem and also opens the door to more projects so I started to research CNCs.

I quickly found that many of the CNCs out there are pricey, require specialized software and are not upgradable or configurable. Then I found Shapeoko; it started as a kickstarter project back in July of 2011 to create an open source, affordable, CNC with a standard design. I have to say the original design out of wood wasn’t that exciting but what it’s turned into is simply amazing. In its current state it utilizes MakerSlides (another Kickstarter project), standard NEMA 17 stepper motors and is entirely open source. It is available for purchase from Inventables in several kit forms.

While researching my purchase I came across this How to build a CNC for $500 post on Reddit that was well researched, had lots of good tips and basically became the blueprint for my order.  In my research I also found that if you would like to mill PCBs, the stability and accuracy of a Dual Drive Upgrade Kit was required so I purchased that as well. Here is my BOM for the project (please note that I’m reusing a Dremel for my spindle but there are many affordable options out there):

Item Parts Shipping Total
Four Steppers from Sparkfun 67.8 11.62 79.42
Shapeoko Mechanical Kit 225 25.14 298.99
Shapeoko Dual Drive Kit (w/o stepper and cable) 39.85
FR1 PCB Blank 9
TinyG 129.99 5.80 135.79
Power Supply from Amazon 23.35 3.98 27.33
EndMill for PCB 3.99 0 3.99
General EndMills 35 2.95 37.95
T-Handle 6.59 0 11.58
Tap 5mm-0.8 4.99
Metric Allen Wrench Set 6.35 0 6.35
Total 601.4

Another big selling point for Shapeoko is the community that has built up around it. They have an active forum and a detailed wiki. Many makers have brought their own ideas for improvements and expansions to Shapeoko and these upgrades are well-documented on the wiki showing parts needed and assembly instructions. Some of the more exiting upgrades and modifications are to replace the spindle with a laser cutter or a 3d printer extruder.

My parts just started coming in this week so expect to see more articles around this topic and hopefully a few freshly milled PCBs.

Jan 05

How to Build a BlinkM Clone

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The original BlinkM was the first in a series of I2C controlled RGB LEDs from ThingM. It’s easy to integrate into projects and control with anything that supports I2C. At its base level it is an ATtiny45 and a Piranha RGB LED. For anyone who wants a simple, elegantly packaged component I would highly recommend that you buy one of these. I am more of a do it yourselfer so I decided to build my own out of parts I had laying around.

Build

Here are materials I used in my project:

  • ATtiny chip (I’ll be using the ATtiny85 but an ATtiny45 will work too)
  • RGB LED with a Common Cathode
  • 3 resistors
  • Jumper cables

This project is very tolerant to variation and you can really do it however you see fit. If you don’t have an RGB LED and want to use individual LEDs that will work. If you have a common anode LED instead of a common cathode LED you will need to use a different firmware package but it’ll work as well. The point is to have fun and learn.

Firmware upload

The firmware for the BlinkM is currently closed source. The reason for this is that the patent for controlling RGB LEDs over I2C is owned by Phillips/NXP. ThingM has licensed these patents to produce their line of BlinkM products. You’ll notice that the license for the BlinkM firmware states that it is for personal use only, not for internal business purposes or for commercial gain. Keep this in mind if you would like to produce a product using this technology.

Because this is closed source it led to the development of an open source alternative: CyzRgb. This firmware is fairly similar to the BlinkM firmware with some additions (like a logarithmic curve for more accurate colors) and some subtractions (it only has 1 script as opposed to the 18 BlinkM has). Some people have noted it’s buggier but if you want to make something that is physically different from the BlinkM (like using a common Anode LED) you will need to use it.

ThingM offers a simple way to upload the firmware through which is called the ReflashBlinkM. This program can be used with the ArduinoISP and can be used to load raw ATtiny chips with their firmware. To do this you’ll need to setup the Arduino ISP wiring as described in the Run Arduino Code on an ATtiny article. Once it’s all connected then start the ReflashBlinkM program:

  1. Select the BlinkM firmware to use (if you are using CyzRgb, select custom and pick the .HEX file from their binary zip file)
  2. Click ArduinoISP on Arduino
  3. Select the port your Arduino is currently on
  4. Click Reflash

ReflashBlinkM using ArduinoISP

It will show the progress in the text at the bottom. When it says “Reflashing Done!” you now are ready to use your ATTiny as a BlinkM.

NOTE: This worked for me when using my UNO but not with my Leonardo.

Wiring

Now that you have an ATtiny programed with the BlinkM (or CyzRgb) firmware it’s time to build the rest of the circuit around it. It’s important to make sure the correct colors are attached to each pin. This circuit can run on 5v or 3.3v.

ATTiny blinkm clone wiring

Use

Now that it’s all hooked up it’s time to test it out. When you first power up a newly flashed BlinkM it will run a default script which flashes through white, red, green, blue and off then starts again.

ThingM offers a package of example code which includes a handful of sketches for controlling it with Arduino. I found it easier to just extract the whole zip file to my Arduino Sketch folder. The all-in-one sketch for controlling everything the BlinkM does is BlinkMTester. With it you can use the serial monitor in ArduinoIDE to view a menu of options. If you are using ArduinoIDE 1.0.2 this will not work, it functions properly on version 1.0.3. If you are using a Leonardo you need to send “?” to get the menu to show up.

BlinkMTester Arduino Sketch Menu

Next Steps

This is an easy component to work with on its own or to integrate into existing products. I created mine as an exploration of the product but I foresee it having functionality in future projects where a diagnostic light is needed. In addition, since it works over I2C it’s compatible with a variety of development boards including the Raspberry Pi.

Nov 23

Gift Ideas for the Maker in Your Life

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For anyone who has a maker in their life you know it can be hard to find a gift for us, especially if you are not a maker yourself. I’ve put together a couple ideas for this holiday season. Below you will find gift ideas for people who are just getting started and some for more experienced makers.

Gifts for Beginners

  • SparkFun Inventor’s Kit for Arduino – This is the kit that started it all for me. It’s great for anyone who wants to get started in the maker world
  • Subscription to Make Magazine – Make Magazine is full of project ideas and news from the maker world
  • Adafruit Tool Kit – Having the right tool for the job makes all the difference. This kit includes all the necessary instruments to get anyone started with DIY electronics

Gifts for Intermediate Makers

  • Arduino Due – This is the latest board from Arduino and it’s still in short supply so check Sparkfun, Adafruit and MakerShed
  • Arduino Micro – This miniature version of the Arduino is great for smaller projects (for those of you reading this on December 24th it’s also available in-store at Radio Shack)
  • Raspberry Pi – This credit card sized computer packs a punch and is hacker friendly
  • Tackle Box – Over time makers collect a lot of parts, sensors and wires. A tackle box is great to help organize all of their supplies. The Plano 7771 is the one I use and it’s been great but it is pretty big, Plano makes a smaller version that would also work well

Gift Certificates

Normally I wouldn’t recommend gift cards because they are impersonal, however many times a project will call for a specific part that you may not anticipate needing. For times like this it’s good for a maker to have a credit available at their favorite website to fill in the necessary parts they need. I would recommend a Sparkfun, Adafuit, MakerShed or HobbyKing Gift Certificate as an additional gift or stocking stuffer.