Tero Karvinen - Make a Mind-Controlled Arduino Robot: Use Your Brain as a Remote

Copyright 2011 Tero Karvinen, Kimmo Karvinen

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• Connect an inexpensive EEG device to Arduino
• Build a robot platform on wheels
• Calculate a percentage value from a potentiometer reading
• Mix colors with an RGB LED
• Play tones with a piezo speaker
• Write a program to avoid lines (tracks)
• Create simple movement routines

In spring 2011, OReilly invited us to Maker Faire, which is the biggest DIY festival in the world. We had to come up with a gimmick for the festival. It had to be both new and simple enough so that everyone could understand how it worked. Cheap EEG devices had just arrived to market and we thought that it would be interesting to couple one of those with a robot.

As a result, we demonstrated the first prototype of the mind-controlled robot at Maker Faire. It was a hit. People queued to try controlling the bot after seeing it in action, as you can see in .

Figure 1. Attendees enjoying our robot at Maker Faire 2011, San Francisco Bay area.

The bot is easy to use. You put on a headband and when you concentrate, the bot moves. Focus more and it goes faster. And its a real robot too; it avoids edges so that it stays on the table.

We built the first prototype () with Ville Valtokari. The robot part was based on soccer bot from Make: Arduino Bots and Gadgets (OReilly, 2011). We read the EEG with a NeuroSky MindWave. The early model had to use a computer as a gateway between Arduino and MindWave, because we were running the MindWave software and our own Python program on the computer.

Figure 2. First prototype of the Mind Controlled Robot.

Maker Faire was great. Arduino was clearly the platform of choice for hardware hackers. There were Arduino robots that could dive and others that could fly. So did we stand a chance of getting any attention to our little bot?

Reactions

Its a fake! Our favorite reaction was disbelief, as it showed that EEG tricks were still new. As if what we were doing was so amazing that it simply had to be just a magic trick. We only heard this about five times, though.

Most of the users simply thought the project was cool. Some were a little skeptical at first, but trying is believing. About 300 visitors tried the device and many more were watching (see ).

Figure 3. Robot at Maker Faire 2011, San Francisco Bay area.

Figure 4. Attendees control our robot at Maker Faire.

We were surprised that it could work in a setting like that. Our prototype could handle hundreds of visitors. Also, the NeuroSky EEG headband was easy to put on and didnt need any user training.

A couple of visitors had probably played with EEG before. They just noted Yep, its a NeuroSky and started talking about something else. Luckily, Brian Jepson had made a 3D-printed version of the soccer bot, so we had a backup gadget to amuse them.

EEG in Your Living Room

Control a computer with just your mind. On one hand, it sounds almost like a sci-fi fantasy. On the other, EEG (electroencephalography) was first used in the early 20th century. What kept you waiting for the future?

EEG is the recording of electrical activity of the brain from the scalp, produced by neurons firing in the brain. The brain cortex produces tiny electrical voltages (1100 V on the scalp). EEG doesnt read your thoughts, but it can tell your general state. For example, EEG can show if you are paying attention or meditating.

The tiny voltages are easily masked by electrical noise from muscles and ambient sources. EEG currents are measured in microvolts (V), which are millionths of a volt:

1 V = 0.001 mV = 10-6 V

Noise from muscle and eye movement can be quite powerful compared to this. In normal buildings, the electrical mains current radiates a 50Hz or 60Hz electromagnetic field. In a laboratory setting, EEG is usually measured in a room that has less interference. At home, the EEG unit must filter out the troublesome signals.

EEG devices used to be prohibitively expensive and annoying to connect, and the data required expert knowledge to interpret. For many years, a starting price for the cheapest EEG units was thousands of dollars. They required conductive gel to connect. Having very clean hair and skin was recommended. Most units used at least 19 electrodes. EEG results were printed on paper and doctors had to take a course to be able to analyze them.