Spike Prime - Self-correcting Codes

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Let's begin

Self correcting codes...

Build

Model:

Pictures:

Building instructions:

• Self-correcting messages reading and writing robot (PNG)

Download building instructions:

• whole system (pdf)

Download stud.io model:

• machine (stud.io)

...description...

Connections:

• left motor - E
• right motor - F
• large motor - B
• calibration light sensor - D
• reading light sensor - C

Programs

Calibration and testiing:

Writing self-correcting code:

Reading self-correcting code:

Download:

• calib_and_test.llsp
• write_hamming.llsp
• read_hamming.llsp

...description...

Measure, analyze, think

• Make your own recording

• Perform experiments with your model and discuss in your group what has happened.

Explore and modify

• Think about how a message can be written so that even after flipping any little bit of it, the message could still be safely read without any disturbance.
• Three methods for students to discover:
  • write every bit 3 times (message length = 3 x L)
  • write every bit two times and add one extra bit - parity of ones in the message (message length = 2 x L + 1)
  • write current parity after every single bit (message length = 2 x L)
  • invent your own method, try to use as little bits as possible

Present

• How would you encode the message using tokens of only one color?
• How could a distance traveled between tokens placed be also used for encoding the message?
• How would the situation change, if one bit could be flipped in every 10 bits that we send instead of in the whole message?
• Prepare a short presentation for other groups. Tell others about your experiments with finding circle centers.

Additional resources

• Download: Circle - all media files