Hacking the Hexbug(TM) Spider with the EMGRobotics Spider Hack Kit and the TI Launchpad

[eric gregori]

This low-cost hack ($44.30 including the cost of the Hexbug spider) converts the remote control toy into a C programmable autonomous robot with a IR range sensor "eye" and a TI MSP430G2231 16bit brain.  After this hack the robot will be able to turn left or right and walk forward or backwards under the control of the EMGRobotics Low-Cost Robot Controller.

The Hexbug(tm) Spider is a remote control walking toy you can buy at your local RadioShack, Target, Walmart, or ToysRus for about $25.00.  From the store, the spider is controlled by a IR remote and can walk forwards, backwards, and turn left or right.  The walking gate of the spider is creepily realistic and fun to watch. 

$15.00 EMGRobotics Spider Hack Kit - Controller board, IR range sensor, battery holder

This hack replaces the remote control receiver board in the spider toy with a fully programmable robot controller (pictured above) making the toy a fully autonomous robot.  The hack uses the EMGRobotics Spider Hack Kit available at www.buildsmartrobots.com and the TI Launchpad available here: http://e2e.ti.com/group/msp430launchpad/w/contents/ordering-launchp....

The EMGRobotics Spider Hack kit includes a robot controller, AAA battery holder, and a  InfraRed(IR) range sensor.  The robot controller is about the size of a quarter and provides bidirectional control of the two DC motors in the spider.  The controller has a 9 pin connector for plugging in the TI Launchpad programmer/debugger and connecting up to six digital sensors or two digital sensors and four analog sensors.

EMGRobotics Low-Cost robot Controller Features

• Independent bidirectional control (forward/reverse) of two 3V DC motors up to 400ma each
• Thermal protection shuts down motor controller if it gets too hot
• Supports any TI MSP430G  14 pin part ( MSP430G2231, 2211, …. )
• Easy in-circuit programming/debugging using the TI Launchpad
• Two User GPIO signals, four GPIO/Analog signals ( when used with a 2231 )
• Runs directly on 2 AA or 2 AAA batteries ( 3 volts )
• Perfect for many programmable robot applications  (line following, maze solving, Sumo, …. )
• Supports 3 volt analog IR sensors
• Example code available at: www.buildsmartrobots.com

You can download the motor controller datasheet here: EMGRoboticsLowCostRobotController.pdf

The controller drives 2 DC motors, and support 6 digital sensors or 2 digital and 4 analog sensors

The IR range sensor connects to one of the controllers digital outputs and analog inputs.  Under software control the IR sensor can detect object up to approximately 1 foot away and provides a estimated range to the object.  Using the provided software the IR sensor provides a range of 0 to 100 for a object distance of 1 to 12 inches respectively.

You can order the TI Launchpad for $4.30 from: http://e2e.ti.com/group/msp430launchpad/w/contents/ordering-launchp...

The TI Launchpad is used to program the EMGRobotics LowCost Robot Controller used in the spider hack kit.  The Launchpad connects to the robot controller using 3 wires, and can fully debug and program the robot controller.  The TI Launchpad comes with the FREE Code Composer Studio professional C compiler and debugger.  Using these tools you can create your program, flash it to the robot controller, and debug your program using breakpoints and stepping as expected from a professional tool.  Time spent learning how to use the TI Launchpad and Code Composer Studio can be referenced on your resume.  These are professional tools used by electronic manufactures around the world.  

 

Connecting the robot controller to the TI Launchpad for programming and debugging

Steps for Hacking the Spider

Tools required: pliers, wire cutters, phillips screwdriver, soldering iron, solder  

You will also need some double sided tape, and some hookup wire.  Of-course you also need the EMGrobotics spider hack kit and the TI Launchpad (see above).

The Hexbug(tm) Spider direct from Radio Shack

After opening the package, flip the spider over and find that battery cover screw

Remove the battery cover

Remove the three screws shown above

Remove the "head"

Remove the batteries and cut the black and red wires

Remove the piece of plastic shown above from the head using the pliers

Unsolder the 4 black/white motor wires from the receiver board, discard the receiver board

Solder the motor wired to the EMGRobotics Low-Cost robot Controller

Screw the head back on the spider with the motor wires going through the slit

Apply double sided tape to spider as shown above

Stick robot controller to spider, add double sided tape to spider head for battery holder

Stick AAA battery holder on head

The IR range sensor that comes with the EMGRobotics Spider Hack Kit

Add double sided tape to back of IR range sensor

Stick IR range sensor to front of AAA battery holder as shown above

Wire IR sensor to Robot Controller as shown

The completed autonomous robot ready for programming using the TI Launchpad

Programming and debugging the robot using the TI Launchpad

For more information check out the Autonomous Spider group on www.buildsmartrobots.com

http://buildsmartrobots.ning.com/group/autonomous-hexbug-spider-hack

Source code MSP430G2452: MSP430G2452_Autonomous_Hexbug_Spider.zip

Source code MSP430G2553: Autonomous_Hexbug_Spider_MSP430G2553_V1.zip

[Don Bertke]

An interesting modification.  I will have to look into the Hexapod kit the next time I am at RS.

I have seen other robots using the same structure and I want to look into how well it scales up.

Could lead to some interesting implementations.

[Steve D]

I have a small 1-cell lipo I bought that I planned to originally hack into my son's spider. Can your kit monitor the voltage to prevent running the lipo empty?

[eric gregori]

@John Smith - I just saw that this morning.

Luckily I saw it before sending out the order for the next batch of boards.  For people who ordered the 14 pin version of the mod kit, I will include the 2231 free of charge, preprogrammed to control the spider.  The next gen version of the board has a 20 pin socket.

@Steve D.  As mentioned above, I was able to modify the board before getting the next batch.  the 20 pin version of the board includes 2 pads for a series diode.  The series diode is needed to drop the 3.7 volt lipo down to 3 volts for the MSP430G.  You can use the A/D converter to monitor battery voltage.   If you order the 14 pin version, you will automatically get the 20 pin version with the diode pads.  I just ordered the new boards, I should have them by Thursday next week.

[Steve D]

Ok, I just placed an order a couple of hours ago.

[eric gregori]

The latest hacking instruction are here:

http://buildsmartrobots.ning.com/profiles/blogs/hacking-the-hexbug-...