My Robot Army @ Maker Faire

For a few years now I’ve been developing an interactive army of delta robots. This ongoing project is fueled by my desire to control many mechanical extremities like an extension of my body (I’m assuming I’m not the only one who fantasizes about robots here).

IMG_1846Since my army doesn’t have a practical application… other than producing pretty light patterns and making the user feel extremely cool for a minute, I guess you’d call it art. In the past I’ve held a Kickstarter to fund the production of my art which I can now happily show at cool events with interesting people; Maker Faire being one of them.

Interactivity and Sprawling Crowds

Last year, for our debut at the big Bay Area Maker Faire, my collaborator, [Mark], and I displayed a smaller sampling of 30 robots for our installation. We also decided to create an interactive aspect for others to experience. After the end of our crowdfunding period last March, we had a little over a month to do any development before the big event, so our options were slim. The easy solution was to jam our delta code into the hand tracking demo which comes with the Xbox Kinect’s Open NI within Processing. This was cool enough to exhibit, but we hadn’t really anticipated how it would go over in an environment as densely packed as the dark room at Maker Faire.

We should have known better. Both of us were aware that there would be many, many children… all with micro hands to confuse and bewilder the Kinect, but we did it anyway. Our only resolve was to implement the feature that would force the Kinect to track one hand at a time, only after being waved at in a very particular fashion. After needing to explain this stipulation to every person who stopped by our booth over the course of the weekend, we decided never to use the Kinect for crowds ever again; lesson learned.

Delta Robots and DMX

Over the past year since that experience, we’ve tripled the size of the installation and brainstormed some better demo ideas. As of now, the robots are all individually addressable over an RS485 bus, and we use the DMX protocol over a CAT5 cable to send commands. If you aren’t familiar with it, DMX is used in show production to control stage lighting… to which there is a super neat and free application called QLC+ that allows you to effectively orchestrate the motion and color of many individual light units; perfect for our cause.

qlcDeltasFunctionally, each of the 84 delta robots in the installation believes that it is a stage light (robots with identity issues). We mapped the X and Y axis of the end effector to the existing pan and tilt values, and the z axis to the beam focus value. The RGB of the LED mounted in the end effector of each delta maps directly to the RGB value of the stage light.

By using the sliders in the QLC+ GUI, I could select groups of robots and create presets for position and color. This was great, someone like me who doesn’t really write a lot of code could whip up impressive choreography with little sweat. Additionally, the program comes with a nice visualizer, where you can layout virtual nodes and view your effects as you develop them.

This is the layout of our installation mapped in QLC+. The teal and purple sliders around each light represent pan and tilt (or in our case X and Y):


Lighting control was an interesting solution. Having autonomous robots this year changed how people responded to them, as they were less like an army you’d command and more of a hypnotic field of glowing grass.

[Mark] and I are considering picking up some flex sensors and maybe playing with the Leap or an EEG headset as a means to reintroduce the interactive aspect. Bottom line, I have this cool new toy that I can’t wait to play with over the summer!

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Robot-Army IRL Plus a Massive Build Log

We went to “the dark room” at Maker Faire once more for an interview with [Sarah] of Robot-Army. She and [Mark], who handles software development for the project, were showing off 30 delta robots who know how to dance. Specifically they’re dancing in unison to the movements of another faire-goer. A Kinect sensor monitors those movements and translates them to matching motions from the deltabots.

You should remember seeing this project back in November. Now that the standards for this model have been worked out it was just a matter of sinking about three-weeks into assembling the army. We’re happy to see that the Kickstarter made it to 250% of the goal at the beginning of March, and with that there are even bigger plans. [Sarah] says the goal remains to fill a room with the robots and a we may even see a much larger version some day.

The interview is a bit short since the Robot-Army booth was right next to Arc Attack (hence the noise-cancelling headphones) and we had to try to get in and out between their ear-drum-shattering interruptions. But you can see a ton more about the project in this huge build log post over on Also check out the Robot-Army webpage. There’s a nice illustration of their adventures at MFBA and the foam Jolly Wrencher made it into the piece!

Build and Control Your Own Robot Army


[Sarah Petkus] has a simple dream. She wants to build and command her own delta robot army. It all began with an illustration she drew of a woman hovering over a field of flowers. The flowers in this case had incandescent light bulbs as blooms. [Sarah] decided to create her image in the real world as an interactive art installation. Her first attempts at moving light flowers were based on a pulley system, which was unreliable and not exactly the graceful movement she imagined. Eventually [Sarah] discovered inverted delta robots. She changed her flower design to a delta, and began building her own delta robots out of parts she had around the house.

A chance meeting with the folks at SYN Shop hackerspace in Las Vegas, NV kicked the project into high gear. [Sarah] switched from using R/C ball links as joints to a simple ball bearing joint. She created her entire design in CAD software and printed it on the hackerspace’s 3d printer. She now has six working prototypes. The robots are all controlled via I2C by an Arduino compatible Nymph board. Six robots doesn’t exactly constitute an army, so [Sarah] had to find a new way to fund her project. She’s currently setting up a project for Kickstarter. [Sarah] will be selling kits for her robots, with the proceeds going toward the realization of her dream of a field of robotic light bulb flowers – Assuming the deltas don’t become sentient and try to take over the world first. [Sarah] posts progress updates to her blog, and has a dedicated site (which we featured on Sunday as part of a Links post) for information about her upcoming Kickstarter campaign.

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