Spike Prime - Self-correcting Codes

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Let's begin

Note: this model requires 1 extra light sensor, and additional extra plastic parts - see bottom of page

Self correcting codes...

Build

Model:

model of machine

Pictures:

robot that can write and read message and correct an error automatically

robot that can write and read message and correct an error automatically

robot that can write and read message and correct an error automatically robot that can write and read message and correct an error automatically

Building instructions:

Download building instructions:

Download stud.io model:

...description...

Connections:

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

Programs

Calibration and testiing:

program

Writing self-correcting code:

program

Reading self-correcting code:

program

Download:

...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


Missing parts

This model cannot be built using one Spike Prime set, unfortunately. It requires an extra light sensor and a couple of additional plastic parts:

extra pieces needed part number, see BrickLink part name comment
2 15458 Technic, Panel Plate 3 x 11 x 1 2 are in Spike Prime set
3 32316 Technic, Liftarm Thick 1 x 5 4 are in Spike Prime set
4 39793 Technic, Pin Connector Block, Liftarm 1 x 3 x 3, black black biscuits, 4 are in Spike Prime Set - can be replaced by 3D printed tokens
2 39793 Technic, Pin Connector Block, Liftarm 1 x 3 x 3, purple purple biscuits, 6 are in Spike Prime Set - can be replaced by 3D printed tokens
2 64782 Technic, Panel Plate 5 x 11 x 1 this is the most problematic part - each one can be replaced by two 15458, but it is a notoriously used part in FLL and it is contained in 90 LEGO sets, if you do not have these, you do not have LEGO :-) If you do not have any, send me an e-mail and I will send them to you.