Vrije Universiteit Brussel

Hacking Keepon

This tutorial is based on a workshop presented at HRI summer school on social robots organized by:

  • Vrije Universiteit Brussel – Robotics & Multibody Mechanics Research Group: Ir Cao Hoang Long, Prof dr ir Bram Vanderborght and Ir Greet Van de Perre
  • Plymouth University: Prof dr ir Tony Belpaeme and James Kennedy


My Keepon, a simple and low-cost version of Keepon robot and the commercial robot, is a black box with two buttons. For human-robot interaction studies, it needs to be controlled by a PC. The goal of this tutorial is to hack the robot so the movements and sounds of My Keepon robot can be controlled independently over a PC Serial communication (UART).

This tutorial is based on the work of:

Required parts and software


The costs for hacking Keepon is around 50€ depending on the configuration.


Download and install the following programs on your laptop. Run everything as administrator of the PC, otherwise some components may not work.

1) Download and install Arduino. A manual how to do so, can be found on: http://arduino.cc/en/Guide/HomePage

2) Download the source code of BeatBots firmware for the Arduino: MyKeepon.ino

3) Download and install MS Visual C# 2010 Express: http://go.microsoft.com/?linkid=9709939

4) Download ViKeepon software: keeponhacking.zip

*** Another possibility is to use a hacked firmware which we can send raw commands to My Keepon (see Appendix)

2) Firmware (Arduino 0023 – Baud rate 9600): keepon_i2c_comm_raw.pde

4) Software: ViKeepon-original.zip

*** If you don’t need to know how My Keepon is hacked, skip 3-Hacking principle and go to 4.

Hacking principle

My Keepon uses two microprocessors to control the movements and the sounds, which talk to each other via I2C protocol.

  • The PS232 (address 0x52) deals with sounds and encoders and is the slave node on the I2C bus.
  • The PS234 (address 0x55) handles driving the H-bridges, main processing (including handling button presses), and is the master node on the I2C bus. At the bottom-right corner of the PCB , there are 4 pads (V, CI, DA and G) of I2C communication. Those pads are connected to A0, A5, A4 and GND of Arduino Uno respectively with a logic voltage converter (5V to 3.3V).

In order to control the My Keepon, the master microprocessor must be changed to be a slave. This step is done by pulling the two I2C lines to the ground for one second after the robot powers up. (For the powering up detection, the V line is connected to Analog pin A0 of Arduino). Therefore it is important first to power up the Arduino and then the robot as will be stated in the start-up procedure.

In order to connect the I2C connection with the USB port of the PC an Arduino will be used with dedicated shield as shown in Fig 2. The shield has simple electronics to do the logic conversion between 5V and 3.3V.

Start hacking!!

STEP 1: Opening My Keepon

To open My Keepon, use a screwdriver for the 4 screws in the back casing of My Keepon. Be careful when opening My Keepon, take care of the position of the different parts, so you are able to reassemble them again later.  With a drill make a hole above the power connector in order to let the four wires enter the casing.

How to open My Keepon casing.

STEP 2: Connect My Keepon hardware to Arduino shield

Attach with some tape the four wires along the black flat cable. Under a transparent plastic cover is the PCB of My Keepon (located in the red rounded rectangle). Solder the four wires in the correct order, solder the other ends to the shield. Check if V of My Keepon is connected with V of Arduino shield, same for CI, DA and G.

Where to solder the wires

STEP 3: Re-assembly

Re-assemble the robot carefully and tighten the back cover with the 4 screws. Power up My Keepon. Without power for Arduino, My Keepon should work as it did at purchase. So My Keepon can still be used as you did when it was purchased.

STEP 4: Connect the hardware to your computer

Plug the Arduino shield to Arduino Uno with the corresponding pins. Then, connect the board to your computer by a USB cable.

Hardware connection

STEP 5: Install the firmware

Open the Arduino IDE and upload the software with .ino extension in the Arduino. This should only be done once. In Control Panel under Devices check the port number to which the Arduino is connected.

Normally My Keepon is now hacked and ready for its first use.

How to use the hacked My Keepon

Important is always to follow this bullet list.

  • 1) Connect the Arduino to My Keepon.
  • 2) Connect the Arduino to a PC using a USB cable.
  • 3) Launch ViKeepon.exe
  • 4) Power up My Keepon.

(It is important to first power Arduino (by the USB cable) and then power up My Keepon as such the Arduino takes over the control.  Normally My Keepon should not move. When you turn on My Keepon, if it starts moving the Arduino has no control. Then, you need to redo the 4 steps in the bullet list.)

When opening the .exe file of ViKeepon, the user interface will open.

Select the correct port (as found in Control Device).

Press the button “Open Port”.

ViKeepon User interface

Press the button “Jump”. If My Keepon jumps, jump as well of joy. You just hacked My Keepon and you have control over him by the ViKeepon User Interface.

The different items of the user interface are as follows. Try the different possibilities to get familiar with the different possibilities of My Keepon.

  • Settings: Configuration of serial port: Port number, Baud Rate, Parity, Data Bits, Stop bits and Close/Open button.
  • Sending and Receiving data window: Send the arbitrary command and display the outgoing and incoming data (commands) – only for debugging.
  • Movement: 2 buttons and 4 numeric track-bars (with for two up-down boxes to change the movements of My Keepon (base pan, tilt, 5 position lean, 4 position height).
  • Mode buttons: start the Dance, Touch, Tempo, Sleep mode and stop button (although functioning is not sure).  
  • Sounds: 15 buttons corresponding to 15 different sounds generated by My Keepon’s hardware.

The program can also read the status of the buttons in the body, responded data is displayed in the data window.

Modifying ViKeepon software

With the Visual Studio programming environment you are able to modify the ViKeepon software. Make a copy of the software so you have a backup and start modifying the software.

In order to modify the software, the basics of the communication protocol must be understood.

UART protocol is used to communicate between computer software and Arduino. Arduino receives data from My Keepon (button states and motor positions) and computer software sends commands to control the movements and sounds of My Keepon. (COM port settings: baud rate 115200, parity none, data bits 8, stop bits 1).

Basically My Keepon reacts to commands that are sent to and received from the robot over the UART protocol using hex values. Persons interested in this can see in appendix the communication protocol. We have a program that uses these commands, persons interested in this can contact the organizers of this workshop.

To make these commands more understandable, the following commands have been offered by BeatBots.

Turn on your My Keepon.  You should receive a "My Keepon detected" message.


Allowable commands (the closing semicolon is required):

    SOUND PLAY <0...63>;

    SOUND REPEAT <0...63>;

    SOUND DELAY <msec>;


    SPEED [PAN, TILT, PONSIDE] <0...255>;

    MOVE PAN <-100...100>;

    MOVE TILT <-100...100>;







Strings that the Arduino can send back to you:









    EMF [PAN, TILT, PONSIDE] [-127...127]


    AUDIO TEMPO [67, 80, 100, 133, 200] (if BPM cannot be detected, this is estimated from power spectral density response)

    AUDIO MEAN [0...64] (the mean of the envelope over a 1.28sec window, max around 64 for very loud music, not updated when motors are moving)

    AUDIO RANGE [0...64] (dynamic range, max 64 for shouting, not updated when motors moving)

    AUDIO ENVELOPE [0...127] (near instantaneous log of the audio amplitude; commented out in code for reduction of data transfer)

    AUDIO BPM [VAL] (estimated beat interval in multiples of 5msec)

The easiest would be to see the code for the different buttons and compare it with the command structure given above.

The first exercise is to make a motion and sound sequence for the button “Harlem Shake”. Search for the string “//ADD HARLEM SHAKE SEQUENCE HERE”. You can add here your code using the allowable commands for the robot.

The second exercise is to modify the reaction of My Keepon when one of the robot’s buttons is pressed.

Search for this string in the software code: “//ADD HERE CODE TO MODIFY MOTION AND SOUNDS OF BUTTON TOP OF HEAD”.

The third exercise is now up to you! We are curious which behaviours you will give to My Keepon. Good luck!!!

Appendix:Communication protocol

Data package structure

1st byte

2nd byte

3rd byte

4th byte to (n+3)th byte

Device Address


Length of data (n)


  • Device Address:
    • 0x52 - PS232: Sounds controller
    • 0x55 - PS234: Movement controller
    • 0x50: Button states
  • Write/Read:
    • 0x00 – Write
    • 0x01 – Read
  • Length of data: numbers of bytes that will be written/read to/from the device
  • Data:
    • Write mode: Device index, Motor position, Movement speed... (see in the I2C protocol commands)
    • Read mode: No data

I2C Protocol Commands

The commands of I2C protocol is used to communicate between Arduino and hardware of My Keepon (Thanks to the research of Nonpolynomial Lab)

  • Device addresses:
    • 0x52 - Sound bank access/playing
    • 0x55 - Motors for turning whole unit
    • 0x50 – Buttons
  • Device Sleep: Assuming no interaction takes place for 3 minutes, the robot will put itself to sleep. This will cause the data/clock lines on the I2C bus to both drops to ground.
  • Device Wakeup: To wake up the device from sleep mode, pull the V line on the exposed I2C pads to ground.

Motor control command structure

This command is used to control all movements of My Keepon: base rotation, forward/backward bending, left/right bending and bobbing.

1st byte

(Device Address)

2nd byte

3rd byte

4th byte


Motor index

Motor position

Motor speed

  • Motor index:
    • Base rotation: 0x04
    • Forward/Backward Bend: 0x02
    • Bobbing and Left/Right Bending: 0x00
  • Motor position:
    • Base rotation: 0x00 – 0xFF
    • Forward/Backward Bend: 0x00 – 0xFF
    • Bobbing: 0x80 – 0xFF
    • Left/Right Bending: 0x00 – 0x7F

Motor macro structure

There are available programs (macros) for specific actions in My Keepon. We are able to run those macros by using motor macro command.

1st byte

(Device Address)

2nd byte

3rd byte




  • Macro: 0x20, 0x21, 0x22, 0x23, 0x24, 0xA0, 0xA1, 0xA2 and 0xA3

Motor Status

Status about the position of motors is retrieved by requesting 13 bytes from the 0x55 device. Due to the lack of information from the manufacturer, we only know the meaning of the last two bytes:

  • Byte 0x0B - Front/Back Encoder
  • Byte 0x0C - Base Rotation Encoder


1st byte

(Device Address)

2nd byte

3rd byte



Sound index

  • Sound index:
    • 0x91 - Up Wakeup Sound
    • 0x92 - Down Wakeup Sound
    • 0x95 - Yawn Down
    • 0x96 - Initial Boot Sound?
    • 0x97 - Sigh
    • 0x9A - Yawn Up
    • 0x9B - Sleep (Sound played before turning off)
    • 0x9C - Chirp
    • 0xAC - Whine
    • 0xBC - Beep noise when head hit
    • 0xBD - Up/Down noise when squatting
    • 0xBF - Sneeze Up
    • 0xC0 - Sneeze Down

Button states

Button status is found from reading a single byte from Device 0x50.

  • Button Index:
    • 0x01 - Music Mode Front Button
    • 0x02 - Unused
    • 0x04 - Top of Head
    • 0x08 - Touch Mode Front Button
    • 0x10 - Left Body (Facing toward user)
    • 0x20 - Front Body
    • 0x40 - Right Body (Facing toward user)
    • 0x80 - Back Body

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