How to Remove Anything from Metal

How to Remove Anything from Metal

Calling all parts recyclers, pick-and-pull repurposers, and lovers of all things metal! Back in MAKE Volume 17, John Todd shared a veritable catalog of ways to remove various substances, from rust to paint to petrified grease, from metal. John breaks down mechanical methods, chemical methods, and the electrolytic method, complete with a how-to for building your own electrolytic conversion tank at home. Check out the full article on Make: Projects. Dig out some old machine parts, and get your shine on!

NOTE: Not all the methods John chronicles have pictures associated with them on Make: Projects, but since the site is a wiki, you can help! If you employ any of the methods, take pics, and add them to the project. The community will thank you!


Zero to Maker: Surrounding Yourself with the Right People

Over the next month-plus, David Lang, something of a reluctant maker, is immersing himself in maker culture and learning as many DIY skills as he can, through a generous arrangement with our pals at TechShop. He’ll be regularly chronicling his efforts in this column — what he’s learning, who he’s meeting, and what hurdles he’s clearing (um… or not). –Gareth

You are the average of the five people you spend the most time with. -Jim Rohn

I first heard this quote when I was working at OCSC Sailing in 2009. I had just completed my sailing certification for chartering boats up to 50 ft., and the quote stopped me in my tracks. It made me reflect on where I was and how I had gotten there. In the year and a half prior, I’d gone from no sailing experience to chartering large sailboats in San Francisco Bay, one of the toughest locations in the country. It was an achievement I was proud of. The strange part was, I didn’t feel any different. In fact, I felt like exactly the same person I’d always been. When I heard the above quote, it all started to make sense. I thought back to other jobs and phases of my life, back to college and high school. In each case, no matter how much I had studied or how much I’d tried, the skills or habits that really took hold could be directly attributed to who I was spending time with.

I have since adopted this as something of a philosophy for how to effectively gain new skills. As a first step on my journey from “Zero to Maker,” I spent a lot of time thinking about who I was going to spending time with, and more importantly, how I was going to convince them to let me hang out! After a cursory search for people to meet in my area (San Francisco), many of the signs pointed to Make: SF, a monthly Meetup group that offers, in their own words, “an opportunity to get started in the maker community. You can meet local makers, learn some new skills and grow from there.”

The August Make: SF meeting at Noisebridge in San Francisco

Lucky for me, the Meetup was only a few days away and a few blocks from my apartment. I arrived at the event a few minutes early and was able to get a tour of Noisebridge, the hackerspace hosting the event, as well as a brief history of the Make: SF group from Malcolm, one of their organizers. During our conversation, I nervously revealed to Malcolm that I was a total beginner, to which he excitedly replied that I had come to the right place. Soon thereafter, the room began to fill with other attendees. Although there were well over twenty people, Malcolm still took the time to go around and have everyone introduce him or herself and say what inspired them to come. The diversity of the crowd was amazing, men and women from every background: an art director, an animator, an artist, a real estate broker, and a software engineer. When Andrew (the other organizer) asked how many of us were new to making and Make: SF, over half of the hands in the room went up. I felt right at home – this would be a safe place to make mistakes and ask questions.

Dave’s first soldering project, a MintyBoost.

We divided into three different groups to begin the evening’s workshop: electronics kits. I broke off into the group that was making the MintyBoost, a device that charges iPhones and iPods with AA batteries. Each of us was given a kit and a soldering iron. This was my first experience with soldering, and that was obvious. Even though I had little idea what I was doing, Malcolm walked us all through it. Anything I missed or didn’t understand, one of the other group members would step in and help me (and vice versa). By the end of the night, I left with a cool new iPhone charger, some basic soldering skills, and a handful of new friends. Not bad for a Tuesday night.

Three ways to spend more time with makers:

1. Meetups – Meetups are a great way to meet people interested in… well, basically anything. Maker meetups are no different. I found my way to Make: SF because they were local, but it’s very likely there are groups near you. If there aren’t any in your area, you can always start your own. Andrew, the original Make: SF organizer, started the group after moving to the Bay Area and finding no groups like the Make: NYC (now dormant) he’d been involved with. Make: SF now has over 730 members and has hosted almost 80 events.

2. Hackerspaces – Hackerspaces are excellent places to meet other makers. I continually hear and read about new hackerspaces opening up all the time. You can find a list of nearly every hackerspace on the planet here. An important note to remember is that each hackerspace is unique. For example, Noisebridge (where the Make: SF Meetup was held) is a different environment than a place like TechShop. Noisebridge is a co-op model, which works well for experienced makers who need a space to hack, whereas TechShop, which works more like a gym membership, is better suited to makers who need access to tools as well as classes and project mentoring.

3. Volunteer! – The maker community is one of the most welcoming bunch of people you could ever find and it’s amazing how much you can learn when you simply offer to help. There are a number of projects and groups that need assistance, even from those of us with limited technical backgrounds. You can peruse the MAKE site or for projects that catch your eye, then email the maker to see if there is any way you can get involved. Attending a Maker Faire or Meetup event is another great avenue to offer your participation.

See the Maker Community Directory for links to hackerspaces, Make: City groups, and other maker/crafter clubs and orgs.

Follow David’s Zero to Maker journey


In the Maker Shed:
New version! Works with the iPhone 4. Build your own MintyBoost, a small and simple (but very powerful) USB charger for your iPod or other MP3 player, camera, cellphone, and any other gadget you can plug into a USB port to charge. Mint tin not included.


Arduino Cookbook Excerpt: Large Tables of Data in Program Memory

Piroulette Console

If you’ve ever made an Arduino-based project involving a large number of text strings, you’ll quickly find the standard-issue Arduino’s 2K of SRAM very limiting. One solution is to save the text in program memory instead, which at 32Kb is much more plentiful.

In the Spring of 2011, I worked on a project with artists Steve Hanson and Elliot Clapp that was part of Apexart’s ”Let it end like this” group show, curated by Todd Zuniga. Steve created a generative questionnaire that polled gallery-goers and presented them with their Last Words. An interactive push-button console and LCD was built by Elliot (pictured above) and we built the thing using an inexpensive Arduino variant from Modern Device. The complete project is documented in the Make: Projects wiki.

Steve’s poetic Last Words took up almost 16K of memory, which was stored in the program memory of the Arduino. Below is an excerpt from the Arduino Cookbook by Michael Margolis that explains how to save and access a large table of data in program memory.

17.3 Storing and Retrieving Numeric Values in Program Memory


You have a lot of constant numeric data and don’t want to allocate this to RAM.


Store numeric variables in program memory (the flash memory used to store Arduino programs).

This sketch adjusts a fading LED for the nonlinear sensitivity of human vision. It stores the values to use in a table of 256 values in program memory rather than RAM.

The sketch is based on Recipe 7.2; see Chapter 7 for a wiring diagram and discussion on driving LEDs. Running this sketch results in a smooth change in brightness with the LED on pin 5 compared to the LED on pin 3:

/* ProgmemCurve sketch
 * uses table in Progmem to convert linear to exponential output
 * See Recipe 7.2 and Figure 7-2

#include   // needed for PROGMEM

// table of exponential values
// generated for values of i from 0 to 255 -> x=round( pow( 2.0, i/32.0) - 1);

const byte table[]PROGMEM = {
   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
   0,   0,   0,   1,   1,   1,   1,   1,   1,   1,   1,   1,   1,   1,   1,   1,
   1,   1,   1,   1,   1,   1,   1,   1,   1,   1,   1,   2,   2,   2,   2,   2,
   2,   2,   2,   2,   2,   2,   2,   2,   2,   2,   3,   3,   3,   3,   3,   3,
   3,   3,   3,   3,   3,   3,   4,   4,   4,   4,   4,   4,   4,   4,   4,   5,
   5,   5,   5,   5,   5,   5,   5,   6,   6,   6,   6,   6,   6,   6,   7,   7,
   7,   7,   7,   8,   8,   8,   8,   8,   9,   9,   9,   9,   9,  10,  10,  10,
  10,  11,  11,  11,  11,  12,  12,  12,  12,  13,  13,  13,  14,  14,  14,  15,
  15,  15,  16,  16,  16,  17,  17,  18,  18,  18,  19,  19,  20,  20,  21,  21,
  22,  22,  23,  23,  24,  24,  25,  25,  26,  26,  27,  28,  28,  29,  30,  30,
  31,  32,  32,  33,  34,  35,  35,  36,  37,  38,  39,  40,  40,  41,  42,  43,
  44,  45,  46,  47,  48,  49,  51,  52,  53,  54,  55,  56,  58,  59,  60,  62,
  63,  64,  66,  67,  69,  70,  72,  73,  75,  77,  78,  80,  82,  84,  86,  88,
  90,  91,  94,  96,  98, 100, 102, 104, 107, 109, 111, 114, 116, 119, 122, 124,
 127, 130, 133, 136, 139, 142, 145, 148, 151, 155, 158, 161, 165, 169, 172, 176,
 180, 184, 188, 192, 196, 201, 205, 210, 214, 219, 224, 229, 234, 239, 244, 250

const int rawLedPin  = 3;           // this LED is fed with raw values
const int adjustedLedPin = 5;       // this LED is driven from table

int brightness = 0;
int increment = 1;

void setup()
  // pins driven by analogWrite do not need to be declared as outputs

void loop()
  if(brightness > 254)
     increment = -1; // count down after reaching 255
  else if(brightness < 1)
    increment =  1; // count up after dropping back down to 0
  brightness = brightness + increment; // increment (or decrement sign is minus)

  // write the brightness value to the LEDs
  analogWrite(rawLedPin, brightness);  // this is the raw value
  int adjustedBrightness = pgm_read_byte(&table[brightness]);  // adjusted value
  analogWrite(adjustedLedPin, adjustedBrightness);

  delay(10); // 10ms for each step change means 2.55 secs to fade up or down


When you need to use a complex expression to calculate a range of values that regularly repeat, it is often better to precalculate the values and include them in a table of values (usually as an array) in the code. This saves the time needed to calculate the values repeatedly when the code runs. The disadvantage concerns the memory needed to place these values in RAM. RAM is limited on Arduino and the much larger program memory space can be used to store constant values. This is particularly helpful for sketches that have large arrays of numbers.

At the top of the sketch, the table is defined with the following expression:

  const byte table[]PROGMEM = {
  0, . . .

PROGMEM tells the compiler that the values are to be stored in program memory rather than RAM. The remainder of the expression is similar to defining a conventional array (see Chapter 2).

The low-level definitions needed to use PROGMEM are contained in a file named pgmspace.h and the sketch includes this as follows:


To adjust the brightness to make the fade look uniform, this recipe adds the following lines to the LED output code used in Recipe 7.2:

  int adjustedBrightness = pgm_read_byte(&table[brightness]);
  analogWrite(adjustedLedPin, adjustedBrightness);

The variable adjustedBrightness is set from a value read from program memory. The expression pgm_read_byte(&table[brightness]); means to return the address of the entry in the table array at the index position given by brightness. Each entry in the table is one byte, so another way to write this expression is:

  pgm_read_byte(table + brightness);

If it is not clear why &table[brightness] is equivalent to table + brightness, don’t worry; use whichever expression makes more sense to you.

Another example is from Recipe 6.5, which used a table for converting an infrared sensor reading into distance. Here is the sketch from that recipe converted to use a table in program memory instead of RAM:

 /* ir-distance_Progmem sketch
  * prints distance & changes LED flash rate
  * depending on distance from IR sensor
  * uses progmem for table */

  #include  // needed when using Progmem

  // table entries are distances in steps of 250 millivolts
  const int TABLE_ENTRIES = 12;
  const int firstElement = 250; // first entry is 250 mV
  const int interval = 250; // millivolts between each element
  // the following is the definition of the table in Program Memory
  const int distanceP[TABLE_ENTRIES] PROGMEM = {
    150,140,130,100,60,50, 40,35,30,25,20,15 };

  // This function reads from Program Memory at the given index
  int getTableEntry(int index)
    int value = pgm_read_word(&distanceP[index]);
    return value;

The remaining code is similar to Recipe 6.5, except that the getTableEntry function is used to get the value from program memory instead of accessing a table in RAM. Here is the revised getDistance function from that recipe:

  int getDistance(int mV)
    if( mV > interval * TABLE_ENTRIES )
      return getTableEntry(TABLE_ENTRIES-1); // the minimum distance
    else {
      int index = mV / interval;
      float frac = (mV % 250) / (float)interval;
      return getTableEntry(index) - ((getTableEntry(index) -
        getTableEntry(index+1)) * frac);

In the Maker Shed:

Arduino Cookbook
Create your own robots, toys, remote controllers, alarms, detectors, and more with Arduino and this guide. Arduino lets artists and designers build a variety of amazing objects and prototypes that interact with the physical world. With this Cookbook, you can dive right in and experiment, thanks to more than a hundred tips and techniques, no matter what your skill level. Here you'll find the examples and advice you need to begin, expand, and enhance your projects right away.


TARDIS Cufflinks

Simon Jansen's TARDIS cufflinks

Looking for that classy Dr. Who touch to add to your threads? Simon Jansen made TARDIS cufflinks from an N-scale model train Police Box. It just took some light metalworking (basically using a razor saw) and painting, and the cufflinks nicely match his TARDIS MAME console.

Asciimation — TARDIS Cufflinks



HP Killing Off TouchPad, Pre – Open Source It?

Hp Touchpad 0-1

HP Killing Off TouchPad, Pre – $1.2 Billion Down The Drain?

…HP reported that it plans to announce that it will discontinue operations for webOS devices, specifically the TouchPad and webOS phones. HP will continue to explore options to optimize the value of webOS software going forward.

HP if you’re going to kill it, open source it – or at least consider giving it away, just like google is doing with Android. On a related note, there will be about 250,000 HP tablet flooding the market, below cost soon. It will be interesting to see what makers do with them.

If You’re Going To Kill It, Open Source It!


Open Source Interlocking, Interactive LED Surface Modules from EMSL

I want to buy, like, 100 of these interlocking motion-responsive LED modules from Evil Mad Science Laboratories and cover an entire wall in my house with them. Unfortunately I can’t afford to do so at the moment, either in terms of money for that many kits or in terms of time to solder the individual boards together.


Oh well, maybe one of you can do it and post some nice video so I can live vicariously.

Long-time readers might recall the original Interactive LED Dining Table, the infamous Interactive LED Coffee Tables, or the third-generation, not-very-creatively-named Interactive LED Panels. All of these surfaces were based on fully-analog circuitry with large circuit boards and a fairly high ratio of LEDs to sensors– typically 20:1.

Octolively, by contrast, is based on smaller, lower-cost circuit board modules, “only” 4×8 inches in size. Part of the reason for this is so that there’s more flexibility in making arbitrarily shaped arrays. Arrays can now be as skinny as 4″ wide, or as wide as you like.

Each module features 8 LEDs and 8 independent proximity sensors– one for each and every LED. The LEDs are (huge) 10 mm types, and that chip in the middle of the board is an (also huge) ATmega164 microcontroller. Each sensor consists of an infrared LED and phototransistor pair, which– together with polling and readout from the microcontroller –acts as reflective motion sensor. The LEDs are spaced on a 2-inch grid, and the edge connectors allow boards to be tiled seamlessly.

As of this writing, the Octolively costs $35 (with generous price breaks starting at 10 units) and will begin shipping from EMSL on Monday.


Neil deGrasse Tyson @neiltyson Please Come To Maker Faire NYC!

This week’s Soapbox column is a request. Well, it’s more like an open letter to astrophysicist, science communicator, and Director of the Hayden Planetarium, Neil deGrasse Tyson, to consider speaking at World Maker Faire, (or just being our special guest) September 17 and 18 at the New York Hall of Science. We know he’s likely busy, but wanted to enlist our/his friends and fans who may know him to see if this can happen. We’ve also tweeted this article to him @neiltyson — perhaps some of you can help with that too! Neil, if you’re reading this, drop a note to if you can make it. If you’re still on the fence, read on while I list why it would be great to see you there!

I’ve been a fan of the recent memes and celebration around Neil deGrasse Tyson as his star has risen in the media landscape. Having Neil at Maker Fair is something I really wanted to try to make happen, and when I saw the video above from a recent appearance of his, I knew the upcoming Faire would be a great place for him to visit, and a great way to inspire makers.

For the folks who do not know Neil yet, here’s a bit about him…

Neil deGrasse Tyson is an American astrophysicist, science communicator, the Frederick P. Rose Director of the Hayden Planetarium at the Rose Center for Earth and Space, and a Research Associate in the Department of Astrophysics at the American Museum of Natural History. Since 2006 he has hosted the educational science television show NOVA scienceNOW on PBS, and has been a frequent guest on The Daily Show, The Colbert Report, Real Time with Bill Maher, and Jeopardy!. It was announced on 5 August 2011 that Tyson will be hosting a new sequel to Carl Sagan’s Cosmos: A Personal Voyage TV series.

Neil, if you haven’t heard of Maker Faire, here’s a bit about what we do. Maker Faire isn’t easy to describe, but we think these videos do a pretty good job of showing what a wonderful and unique festival it is. Started in San Mateo, CA, in 2006, and also held in Detroit and New York, Maker Faire is the premier event for grassroots American innovation. As the World’s Largest DIY Festival, this two-day family friendly event has something for everyone — a showcase of invention, creativity, and resourcefulness, and a celebration of the maker mindset. With hundreds of thousands of people going to Maker Faires each year, we’ve also had other well-known folks like Mike Rowe (Dirt Jobs) and Adam Savage (Mythbusters) be part of these celebrations of science, making, and engineering.

So that’s a little about us — more about you! Here are some of the “best of” Neil deGrasse Tyson videos, memes, and more. I think when you look at all of them together, in context of the challenges ahead (we need more people making things), you being at Maker Faire is a good fit.

“We Stopped Dreaming” — Maker Faire is one of the few places left where dreams come true. We gather together to share what we’ve actually made and share how we did it. With NASA budgets slashed and the future of space exploration looking grim, we’ll need to make more scientists and engineers than ever if we’re going to get out of this funk.

You said:

“I see the most powerful particle accelerators in some other country,” Tyson said. “The fastest trains are built by Germany and are running in China right now. I see our infrastructure collapsing, no one dreaming about tomorrow, and everybody thinks they can put a band aid on one problem or another.”

We want to fix that. It won’t happen overnight, but I can tell you first-hand that since we’ve started MAKE, we’ve made more engineers. We’ve been doing MAKE for about 6 years now, and each year, parents come up to me at Maker Faires and talk about how their teenager (now) just graduated and is an engineer, and how five or six years ago they “didn’t do anything, until they started doing the projects in MAKE, then it was full speed ahead!” We hearing this over and over, but we need more people like you, Neil, talking about how important it is to make things and why.

You talk like us. You said:

“If you’re scientifically literate the world looks very different to you.”

We have a slightly different dialect, but we say the same things. Technology can be a mystery, but once you can make something, or take it apart, you can understand it. It’s harder to get tricked or fooled. We like to say “IF YOU CAN’T OPEN IT, YOU DON’T OWN IT!”

Carl Sagan-550X456

You’re doing a new Cosmos — this is awesome. We all want to watch it and help it succeed. There are millions of people who visit the MAKE site each month — we know they want to see you take on the task of becoming the next Carl Sagan for many. When you talk with makers and ask them who their heroes are, you’ll hear a lot of them talk about Carl getting them excited about learning.

More than three decades after it aired, Carl Sagan’s groundbreaking, brilliant 13-part TV series Cosmos:A Personal Voyage will finally get a sequel.

Cosmos, which originally ran in 1980 and was rerun many times over the following decade, is widely regarded as one of the first, and best, TV shows to make science accessible to everyone. You can watch the show now on Hulu, but despite its brilliance, it’s still a show from more than 30 years ago, and you can tell — the special effects are primitive by today’s standards, but more importantly some of the content has been superseded by discoveries in the intervening years.

So, it’s high time someone made a sequel to it, and now someone is! In partnership with Sagan’s colleagues Ann Druyan (who is also his widow) and Steven Soter, Seth MacFarlane — yes, that Seth MacFarlane — is going to produce a new 13-part series to serve as a sequel and modern update to Sagan’s masterpiece.

Taking over the hosting duties will be none other than well-known astrophysicist Neil deGrasse Tyson, who has served as host of NOVA ScienceNOW on PBS for the past five years, so he has plenty of experience making science accessible to the general public. It would be difficult to think of anyone who would be better able to succeed the late, great Carl Sagan.

Maker Faire NYC is a good thing for New York. I live a few blocks from ground zero, just like you do, here in downtown NYC. You go to the same gym as me, but I’ve never said hi because that might be weird, but anyway, in addition to writing here at MAKE I work/live in a real electronics factory. We have a laser cutter, pick-and-place machine, and Limor Fried (my partner and founder of Adafruit Industries) is an engineer. Our goal is to make more people who can make things. As we approach the 10-year anniversary of 9/11, we are proud to have our company here, being part of MAKE, and having a Maker Faire helps NYC continue to grow. There are a few science events, but this is the only one that I would say is more of an engineering event — a subtle but notable difference.

I 100% agree Pluto wasn’t a planet, most makers agree (OK, I think, maybe, I don’t really know — they’ll tell us in the comments below). This isn’t really a reason to come to Maker Faire, but know you’ll be amongst friends.

OK, so hopefully I made the case here. I’m hoping folks politely tweet you encouraging you to attend (and speak!) and if you’ve read this far, please drop us a line on the special email address we created just for this!

Folks, post up in the comments and we’ll see you at Maker Faire NYC in a month!


Discounted Maker Faire Tix at NY RadioShack Locations

View Radio Shack Maker Faire Ticket Locations in a full screen map

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Check out this nifty Google map that shows which RadioShack locations throughout New York City and beyond are offering discounted World Maker Faire tickets. Discounted One Day Tickets will be available at these RadioShack locations throughout New York. Save $5 per ticket, avoid lines onsite, and support your local community by visiting these RadioShack locations up through the event.

World Maker Faire, Sept 17, 18, New York Hall of Science


MorpHex = Conventional Hexapod + 2

This is Norweigian Kåre Halvorsen’s MorpHex project.


MorpHex improves upon the traditional static hexapod body by the addition of a set of six radially-irising arms, each of which carries the top leg joint of one of the six legs. By expanding or contracting the iris, the diameter of MorpHex’s overall footprint can be dynamically adjusted. The embedded video above shows off this capability nicely.


In the next stage of development, MorpHex will mount a section of a hollow hemisphere at the end of each leg as a “foot.” Maximally contracting the legs will align these sections to enclose MorpHex’s lower body in a continuous hemisphere which, in the final version, will be contiguous with an upper hemisphere mounted on top of the body. I wonder if Kåre has considered mounting another six limbs with another six sphere-sections upside down on top of the first? [via Hack a Day]



In the Maker Shed: Learn to Solder Kit

Are your soldering skills rusty or non-existent? The Maker Shed can help with the Learn to Solder Kit! The kit has everything you need to build a flashing European-style siren including a 30W soldering iron, wire cutters, and lead-free solder. After you build the siren you can use the included tools again and again to build your own projects! Perfect for beginners ages 10 and up and a great way to get started in electronics.


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