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I want to put some finishing touches on my TinyCNC drawing robot before Maker Faire, but I’m a little ambivalent about how best to show off it’s drawing/CNC abilities.1 There are several excellent ways to control such a robot – perhaps you can help me decide?  My thought is that an IR remote would be really nifty, since I could just hand the “control” to someone and they could play with the robot, getting it to draw something.  Then again, feeding gcode to the ‘bot and having it actually draw something semi-recognizable would also be great.2

What's the best way to control a TinyCNC / drawing robot?

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For context, here’s the links to the various possible ideas for control mechanisms:

Please vote above3 and let me know what you’d like to see working at Maker Faire!

  1. Photo by tenaciousme []
  2. Heck, the robots are small enough that I’ll probably bring more than one. []
  3. Or, comment below []

TinyCNC – Working Keypad UI

If you’re still on the fence about trying to build your own drawing robot/plotterbot, take heart.  (Skip to the bottom of the post if you want to check out the latest 3D printable files and Arduino code.)  If a relative newbie such as myself can make a go of it, I’m pretty sure you can too.

Last night1 I finally got the little ‘bot to really make use of the keypad as a modest user interface.  The robot is now using the USB cable purely for power purposes, rather than requiring the serial connection to the Arduino serial monitor as well drawing power from the USB port.  Now I can just connect the USB cable to a random USB charging device and operate the robot in a meaningful way by using the keypad.

In addition to the keypad direction system described in a previous post, now the “*” and “#” keys also have a usage.  The “*” key now starts and stops the Arduino from logging the inputs.2 Pressing the “#” key will play the most recently recorded inputs.

My record/playback system is super hacky and the ‘bot sometimes jitters before carrying out a command.  I’ll also have to implement a few additional changes to the design of Y axis before it can hold a pen reasonably stead.

But, it works!

Download the latest stable 3D printable parts on Thingiverse, latest Arduino sketch from Github, and play with one for yourself!

  1. Well, technically this morning? []
  2. If you forget whether it has been toggled to start or stop recording, the robot performs a little “wave” with the Z axis when it is ready to start recording and three little “waves” when it stops recording. []

Drawing By Numbers

Draw on the go with a small Arduino-powered CNC robot!

Draw by numbers!  Plus the pound and star keys, if you want.

In preparation for Benicia Mini Maker Faire 2016 this last weekend I finally got my TinyCNC working with this sweet Adafruit numeric keypad!  Now using the robot is so easy, even a 17-month old can operate it!1

I’ve programmed the ‘bot to interpret to move as follows:

  • 4 = Left
  • 6 = Right
  • 2 = Back
  • 8 = Forward
  • 5 = Up
  • 0 = Down

I believe the directional keys move the ‘bot in 3mm increments, but this is easily adjusted in the code to whatever you prefer.  I’ve also set the 1, 3, 7, and 9 keys to move in the four combinations of X / Y max / min travel.2

Print a TinyCNC for yourself by getting the STL’s on Thingiverse.  Also, I’m still getting the hang of this whole GitHub thing, but if you have a similar keypad and want to give the Arduino sketch a shot, check it out here.  You’ll want the one entitled, “TinyCNC Keypad.”

  1. My younger daughter has really gotten a kick out of the ‘bot – a tiny robot she can actually control all by herself. []
  2. My daughter enjoys these four buttons the most – since they cause the most dramatic change in the ‘bot. []

Drawing robot supplies shopping list

Going Shopping

Going Shopping

Sometimes it can be difficult to figure out where to get started on a project.1 Once you’ve read through the build instructions, you’re going to need to get your hands on some parts.  I’ve provided a “shopping list” of sorts below:2

I’ve got more to say about each of these fantastic suppliers, but that is another post in and of itself.  Feel free to shoot me an email or leave a comment if you just can’t wait.

  1. Photo courtesy of polycart []
  2. No kickbacks, just a happy customer from each of these suppliers []

Tiny CNC Drawing Robot – Cost Estimate

A really tiny CNC - a work in progress

A really tiny CNC – a work in progress

One of my goals in designing/building this little robot was to make it really cheap and easy to build.  I’d like to think I’m headed in the right direction.

I would estimate the cost of building (a completed version of) this little robot as follows:

  1. 3x Micro Servos at $6/each
  2. 1x Arduino Uno at $30
  3. 30.6g of ABS plastic for roughly $1.53

I’m going to exclude the bits of wire and pen, and estimate the materials cost of this robot at $49.53 which I’ll round up to about $50.00 since I have to design and print a few more plastics parts.  Basically, if you’ve already got a 3D printer, plenty of plastic, and an Arduino lying around, there’s no reason you couldn’t have a similar robot up and running in no time for about $20.

It’s my hope to use my newly won Adafruit Trinket 5v, courtesy of Hackaday and Adafruit1 , it might even be possible to power all three servos off of a single Trinket ($8) and bring the total cost of the project down to around $28 plus little bits of wire and a pen.

Although I give vague building instructions on the Thingiverse page for the parts of this robot, I hope to have an Ikea/Lego style set of instructions ready in the next day or so.  So far there are only 8 parts (including the two servo motors), so even a team of monkeys taking a break from writing Shakespeare could manage to assemble one of these in a few minutes.

  1. Thanks again!!! []