1. Controlling the Air Swimming Shark with your Brainwaves How does it work?
Nick Carter 7/25/2016
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2. The Idea
In researching EEG Sensors I found Open EEG and their application idea.
I wanted to do it on the cheap
thus, MindFlex Game has 1 or 2 EEG sensor inputs.

3. Shark being driven at Nova Labs
EEG Headset
MindFlex Game RF IR
Shark Remote
Arduino
For Video see:

4. Block Diagram - Project Building Blocks
Program in Arduino to translate MindFlex signals to Shark Remote signals
Circuit* to make MindFlex compatible with Arduino
Circuit* to make Shark Remote buttons compatible with Arduino
Shark Remote Modified to get button signals
MindFlex Toy
Player Brain Control Signals.
1 EEG Sensor ?? ?? ?? ??

5. Interface Mindflex to Arduino - 1
What signals are available
Motor control
Physically moves
Seems to have speed/position feedback
Physical access?
LED control
Easy access
3 intensities already decoded
2 player access
Other
Hack controller?
More difficult – little info available
I chose the LED control

6. Interface Mindflex to Arduino - 2
Interface to LEDs – how do I monitor them
What is the drive LED signal
Light intensity varies with Pulse Width Modulated (PWM) signal
How do I interface to it, Arduino has Analog and Digital inputs.
Digital interfacing requires careful timing and there are 6 lights.
Analog interfacing is easy. I used an RC network to convert PWM to analog.
Use threshold values in the Arduino to decide if LEDs are “ON/OFF” for control purposes

7. Wiring inside MindFlex Base Unit
LEDs
LEDs
Connectors
LED Wiring to Connectors
LED Wiring to Connectors

8. Arduino Code Major Code Blocks – Loop this
Read Analog Inputs
Compare Analog inputs with thresholds to see if they represent ON or OFF. Since the filtered signal is a saw tooth, we need a big hysteresis. (Difference between thresholds more than saw tooth height.)
Decide Shark Drive action based on LED ON/OFF
Forward, Turn Left, Turn Right, Up, Down
Send signals to “push” the Remote Control buttons
Turn solid state relays ON/OFF with Digital outputs
Create Sequences for Drive actions as callable functions
Forward = side to side tail wag, alternate L/R button press
Turn Left = Short wag R, Long wag L. (Turn R = opposite)
Up/Down – requires 2nd player, use manual control at first
Using one player,
Activate Drive sequence Forward when Green LED is on,
Activate turn Left or Right when Orange LED is on,
Change turn direction every time Orange is achieved after Green.
Notes:
2 Player LED signal sets are available – players would have to coordinate but more control information is available.
Preprogrammed Shark drive sequences could be used without the “mind control.” just using the Arduino – or using other input means.

9. Interface Arduino to Shark Remote control
Remote control has push buttons to control the Shark.
3 buttons close to a common signal
1 button does not**
I need to wire out the button contact points
I will wire to a convenient external connector for my relay board
**This was my remote version. Some versions of remote may have all buttons with common connection to switches drivable from Arduino, but relay drive is universal.
Ribbon cable with 6 pin connector to Relay Board

10. Interface Arduino to Shark Remote control
Solid State Relay
I need to close the Push Button circuit from Arduino
I cannot drive directly from digital outputs for all
I need a relay (isolated contact) for the 1 contact
I designed a quad Solid State Relay board using Eagle CAD, PCB from OSHPark. Components from Digikey.
Ribbon Cable Connector mate

11. Integrating the Parts Couple everything with connectors
Breadboard interface Arduino to Game
Arduino Monitor on PC.
Values sent back
1=LED_ON, 0=LED_OFF
Arduino Analog level
REMOTE
GONDOLA IR
Wagging the tail
from the PC
(This pic shows EV3 remote not shark remote)

12. The Shark
I used “Air Swimming Shark” from Internet. (Other fish types available)
Price range $15 to $50
Requires about $15 of helium to inflate
I bought a party balloon kit for $25 with helium canister. So far it did 1 full inflate + 1 top-up – more left still.
Shark stays inflated a few days then may need to be topped up.
Cannot assemble shark until inflated. 2 people needed for best assembly.
Fins and control electronics are held with double sided sticky tape + overlay reinforcements. (Tricky with one person)
Neutral buoyance is achieved using clay/putty (supplied). I found I had to tape some to front of shark to balance it.
Normal leveling is supposed to be achieved using “climb/dive “ attitude adjustment using the remote to move the electronics module (gondola) to front or rear with rack /pinion gearing.
Propulsion forwards is by side to side tail wags using remote to wag left and right alternately (separate buttons)
Turn is done using the wag buttons to wag more one way than the other, or holding button down will only wag to one side.

13. Issues
Shark fin reinforcement tape is light and sticks to itself easily. Can be difficult to apply.
My placement of the control gondola using lowest altitude placement was not far enough forward to enable proper climb dive control (I added more clay taped to front of shark.)
You can’t tell until you stick it on then it is too late.
The fins came off in my car driving 7 miles and the shark was stressed against roof etc.. They could be re-stuck but for how long?
The control gondola did not stick well to underside, curvature did not match shark. One end broke and I had to hot-glue it.
The tail drive mechanism frequently became stuck and had to be manually released (forced) to continue wagging.
From time to time it gets “directionally challenged” and needs manual intervention to put it back on course (see video)
BUT…..despite these issues, it is a fun toy and people really like it 