Let's Make Robots!

Prep for Maker Faire 2013 NYC

Howdy Y'all,

We are starting to get close to Maker Faire this year and I suppose it is time to start getting some ducks in a row.

I am planning on attending Education Day as well as the Fair itself, representing both Let's Make Robots and Rocket Brand Studios. All are welcome of course, as well as your bots. It also looks like I will be the Big Chief of the Booth this year so feel free to drop me a line with questions etc., I am the "super head-guy coordinator guy of LMR at MF, guy".

Electromagnet Calculations

Hey guys, I think I really just need some help with Google search terms here...

I am making a solenoid, or more specifically, the coil part. I need to find an online calculator or some equations to figure out the proper gauge and number of wraps to give me a given resistance and/or strength. I am sure they are out there but for the life of me, I can not seem to put together the proper set of Google search terms to get me to where I need to be. I have been googling for over an hour now finding nothing of any use.

Drive Stepper (4th axis) off of PWM Spindle Control Ouput

Sorry 'bout this one, I am just sorta "thinking aloud" here, feel free to brainstorm with me, there is no real specific question here.

I want to use the 4th axis (horizontal rotary axis) as a lathe on my CNC. The X,Y,Z would operate normally, the only difference would be that they would be grinding away at a chunk of something spinning, as aposed to sheet-goods clamped down to the table.

Help with steering linkages (Not a robot)

Hey guys, I know this is not a robot but I could really use a second set of eyes on this one...

LMR/ HTML/ iFrame not playing nice

Hey guys, I am trying to embed a Google Docs (Google Drive) Presentation in a LMR post. I can paste the html into the HTML pop-up window, but after hitting "update" nothing happens and my html code is missing if I reopen the HTML editor.

I can get the iFrame to work via disabling rich-text, but again, it is nowhere to be found (also, again, the html code disappears) if I save or otherwise update the post.

I will post the code below, I am not sure how this post will handle it. 

Binary Number directly from Arduino I/O pins?

Hey guys, I know there has got to be a way to do this, but I can't seem to find it at the Arduino reference page and I don't seem to be using the correct google terms.

I have a 4-bit parallel output from a chip going to 4 digital input pins on an arduino. The chip I am using is putting out a nibble of 4 bits representing a number in binary form. I need the arduino to read the state of these 4 pins and give me a number. I have done this via Picaxe in the past, but I can't seem to find the same thing in Arduino.

Rocket Brand Studios 48 hour thing... Links now available

Hey guys, 

Rocket Brand Studios will be participating in Deconstruction 2013. (woo hoo!)

Starting Friday afternoon (2.22.13), I will start building...   ...something. 48 hours later I will be dead --or-- have something really cool built. --And it is all going to be live streamed!


You will be able to watch everything on the front page at

Rocket Brand Studios

Need Sumo built (as a gig)

Hey guys,

I have a customer in Italy that I have done a bunch of custom robots for. He recently has requested a sumo bot --a couple/few of them actually, coded and ready to go. Just like a toy from a toy store, but with wires showing. 

This is a real gig, and I will happily pass it on to whomever wants it and there will be a fair bit of change at the end.