Go back to Product Documents NavigationÂ
 Go back to KOI Documents NavigationÂ
 Go back to KOI Coding with MakeCodeÂ
Â
KOI is able to find and track circles in a scene.
Â
Â
Load the KOI Extension: https://github.com/KittenBot/pxt-koi
Blocks for circle tracing:

Â
Sample Program
Threshold
Threshold affects the detection rate, testing and fine tuning the value is needed for achieving the best results.
A higher threshold value decreases interference and noise, but detection difficulty increases at the same time, please trial and fine tune for different scenarios.
Â
Program Flow
Download the program to Micro:bit, then press A on the Micro:bit.
The radius of the circle is shown on the Micro:bit while its coordinates are shown on the KOI.
Â
Advanced Program
The information becomes more easily readable if we add an OLED screen.
Â
Connecting an OLED
Connect an OLED panel to the I2C port of your Robotbit/Armourbit.
Â
Sample Program
Load the extension for OLED: https://github.com/KittenBot/pxt-oled
Â
Sample Program
1. Circle Tracing (Extension0.5.7)
2. Circle Tracing /w OLED (Extension0.5.7)
Â
Extension Version and Updates
There may be updates to extensions periodically, please refer to the following link to update/downgrade your extension.
Â
FAQ
Q1: There is no reaction after pressing the buttons on the Micro:bit.
A1: This is because KOI has a longer boot time than Micro:bit. When the power is turned on, Micro:bit has already ran the code for KOI initialization before KOI is ready.
Solution: Reset your Micro:bit after KOI has been turned on. (The trick is to let KOI power on completely before initialization.)
Q2: Does KOI work with 3V input?
A2: No, KOI only works with 5V.
Q3: How do I improve detection rate?
Â
- Adjust the threshold value.
- Keep a clean background.
- Make sure the circle has a sharp outline.
Â
If you have any question, please feel free to contact us at Discord, we will always be there to help.
Â
KittenBot Team
Â
Â
 Go back to Product Documents NavigationÂ