Spike Prime - Self-correcting Codes
From RoboWiki
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:
Pictures:
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:
Writing self-correcting code:
Reading self-correcting code:
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
- Download: Self-correcting Codes - all media files
- 3D printed biscuit replacement: biscuit-replacement.stl
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. |
