Adaptive Kayaking & Scuba Diving. Disabled, Handicapped. Adaptive Sports, Adapted

  Disabled Adventurers                              
      227 Tennyson St., Thousand Oaks, CA 91360             (805) 427-1128   

Bringing the sport of kayaking to the disabled through training and development of adaptive equipment!



Dual-Motor SIP&PUFF Controlled Kayak System
Click on the photo for a full sized version.

My design is a stand-alone fixture consisting of a Deck Plate that can be fastened to ANY kayak.
Off each end of the plate is a pontoon which rides above a fixed direction trolling motor.
Each system has two pontoons and two trolling motors.
There is no need for a rudder or any mechanism to steer the trolling motors,
as turning is accomplished by varying the speed of one or the other trolling motors.

The Motor Control Program is entirely controlled by a single SIP&PUFF switch!





A highly disabled (quadriplegic) person can fully control the kayak via a SIP & PUFF Switch
(Picture Steven Hawking or Christopher Reeve in their wheelchair).

The on-board Arduino Duemilanove Microcontroller puts the Motor Driver into Serial Input Control Mode and accepts Sip&Puff Switch inputs from the Rider. It then sends appropriate Serial Commands to the Motor Driver to operate the two Drive Motors. Split-second (0.1 - 0.6 seconds) Sips and Puffs control Left and Right Turning, respectively, and slightly longer (0.6 - 2.5 seconds) Sips & Puffs control REV and FWD movement. Even longer Sips and Puffs Stop the motors or command them equally to Full Speed. Steering is accomplished via differential motor speed.

At any time, the Safety Observer can (turn on the RC Transmitter and) transmit a Full Throttle command which the Arduino detects via this Receiver Channel being connected directly to it.

The Arduino then sends Serial commands to the Motor Driver to put it into RC Input Control Mode.

The Safety Observer now has full direct control of the Motor Driver via the AILERON and ELEVATOR channels of the Receiver being connected directly to the RC Inputs of the Driver (in MIXED Mode). The kayak is now essentially a large robot.

If the Safety Observer decides to pass control back to the Rider, a Throttle Off command is Transmitted, or the transmitter is simply turned off. The Arduino detects this condition and sends Serial Input Control Mode Commands to the Motor Driver giving control of the Motor Driver back to the Rider via Sip&Puff inputs into the Arduino. Note that the Arduino controls the Motor Driver via Serial Commands Only.

The Rudder Channel of the Receiver is reserved to actuate high-current switches which will physically disconnect the Drive Motors from the Motor Driver.

Top speed is just under 3.7 MPH, according to my GPS. After 4 hours and 6.2+ miles, the motors were still running strong, producing ~3.3 MPH into the wind, and the main battery still showed 12.15 volts. The Motor Driver and Arduino Controller, as well as the Sip&Puff Interface, will continue to operate down to 5 volts.

My total cost for this project so far, not including the Spectrum DX7 Transmitter, is around $1300, with the biggest expenses being: Motor Driver ($430), 2 Min Kota Trolling Motors ($240), Aluminum ($135), Battery ($90), and Charger ($60). Also: LEDs, Cables, Connectors, Switches, and I.C.s ($175+), RC Receiver ($60), Cam Bolts ($40), Backup Arduino uController ($35), etc... Note that I actually did make it all the way through my Design & Development process without blowing up the original Arduino!

Although I have been contemplating this project since 2006, obtaining the Arduino uController really gave me a jump-start, and I officially started working on it in mid-June of this year (06/17/09). I had the project completely working on August 20, 2009. Compare this to the Cal Poly Solo Quad project (Google: Cal Poly Solo Quad). Cal Poly engineers considered Remote Control Assist impossible to incorporate into their design.

RC Remote Control override capability is incorporated into this design mainly to allow a safety observer to assist the highly disabled rider who will be operating the kayak truely "hands-free" via the Sip & Puff switch interface.

It is, however, still possible that more able-bodied riders, and fishermen, for instance, may like to control the kayak themselves via the RC Transmitter. Still, I have found that using the Sip & Puff interface is WAY more fatigue-free. In open spaces, long periods of travel are somewhat "set and forget" and minor course changes, or corrections, are accomplished with the lightest (and shortest) of tiny sips and puffs against the straw.

The caveat is that the RC Transmitter is a bit more intuitive and provides for extremely fine control of the kayak. With a few minutes of practice, though, a Sip & Puff rider can learn to, for instance, back the kayak precisely to the corner of a dock, or steer down a winding channelway of 10-15 feet in width.

The following files describe the system, and can be downloaded via the provided links:

- SystemDiagram.gif is a complete diagram of the system, including Operator Panel, Motor Driver, and Motor circuitry.

- SNPCTRL.EXE is a program which accurately simulates interaction with the control unit,
   except that SIPS and PUFFS are simulated by pressing the <Ctrl> and <Alt> keys.

   Remember to enter the Startup Sequence first!
   See "The SNPCTRL.EXE Program" below for more info!

- SANDPSWITCH.GIF illustrates a typical SIP&PUFF switch.

- OP-PANEL.GIF is a schematic diagram for the Operator Display Panel.

To download the Control Program, click on the SNPCTRL.EXE link, or type:
    into the Address Bar of Internet Explorer, press <Enter>, select Run or Save.

This design has several great advantages over a single-motor system:

1: No need to develop a directional control system as turning is accomplished by differential motor speed.
   An inexpensive single-board computer (eg. Arduino Duemilinove) drives the inputs of the
   motor drive circuitry. Functionality is easily modified as a S/W change.

2: Designed as a stand-alone assembly, it is designed for use on just about any kayak, particularly sit-on-tops.
   The user does not need to buy another kayak, or any at all if they can rent one.
   The wing can be easily positioned in front of or behind the user.

3: The SIP&PUFF interface is fatigue free, and does not bring any electrical circuitry up to the user.
   All electrical and electronics components are contained in a (semi-)waterproof enclosure typically placed
   above the deck plate. Only the battery is separate, and can be positioned in front of or behind the rider.

4: The system incorporates an RC Remote Control override by which a safety observer can take full
   and precise control over the kayak in any case where the rider is unable to control it as required.

5: All switches are debounced and timed in the software.


1. An RC Remote Control override capability.

2. A Lanyard Switch to detect the rider falling off without capsizing.

3. A toggle switch on the Control Unit to ensure motors off during boarding, etc.

4. A "secret" system startup sequence and "Practice Mode" to allow safe power-up.

5. A remotely-operated switch to electrically disconnect both motors in case of major system failure.


--Download and execute the SNPCTRL.EXE program.
--The program runs best in full-screen mode. Press <Ctrl-Enter> to switch to full-screen.
--Enter the Startup Sequence first! <Alt><Ctrl><Alt><Ctrl>
--Pressing <Ctrl> and <Alt> simulates a Sip and Puff into the system.
--Press <M> to simulate Man-Overboard or Capsize.   Press <Esc> to exit the program.

Timing for the length of Sips and Puffs is very accurate in the simulator, and feedback on timing is given in the Switch Status (center-screen).

I am guessing that many people will have the ability to make single key-presses on a keyboard with existing adaptive computer equipment, however I am not sure that all such equipment would provide for control of the amount of time that a key is held down. If this provision does not exist, an assistant would be required to demonstrate the interface. Prospective users of the system should be encouraged to play with, or view operation of, the simulator in advance of their time out on the water with the kayak.

In the future, I hope to build a second "real" control system that can be used as a simulator for this purpose. I am in the process of designing a PCB (Printed Circuit Board) that will encompass all the electronic components, and nearly all of the electrical components, of the system.

RULES IMPLEMENTED IN THE CODE: <M> simulates Man-Overboard, Capsize, or Motor Overload.

Very long (held) sips and puffs are simulated in this code.
(See Actual Operating Code notes below)

The maximum differential between the left and right motors is 7.

Reverse motor speeds are limited to 5 (50% power).

Hard turns slow the craft and move through turning on point.

Changing speed when one motor is in reverse and the other is in forward
causes both motors to stop until the next comand is given.

When one motor is at stop, that motor waits for other motor to be at stop
before proceeding in opposite direction with speed change command.

In the Actual Operating Code:

When ever both motors reach stop in very long speed change commands,
the user must release the switch in order to issue further commands.

For instance...
The craft is set to fast forward and user holds a very long Sip:
Both motors will decrease to stop and will not go into reverse
until the user releases the Sip and then gives a further command.