sk8
robotzone, parent company, winfield, kansas
actobotics, parts brand name
servocity, distributor
skateboard deck
- length: 700mm
- width: 200mm (at widest point)
- height: 110mm (to top of deck, when flat)
- height low edge: 90mm (at maximum tilt, at widest point)
- height high edge: 130mm
weight plate
- id: 25mm (.98in)
- od: 150mm (5.9in)
- weight: 2.5kg
linear actuator (obsolete idea)
- qty: 2 pieces,
- retracted length: 250mm (10 in),
- extended length: 370mm (15 in),
- stroke length: 120mm (5 in),
- speed: 60mm/s (2.5 in/s),
- force: 30 N
- include: 4 mounting brackets, 2 at each end of each piece
springs
- closed ground
- outside diameter 24 mm (.944882 in)
- free length 16 mm (.629921 in)
- wire diameter 1mm (.0393701 in)
- coils 4 total
- product number: century 3663
- supplier: century spring corp, mw industries,
object detection
pad angles
sk8mini
Adjust speed for helm, for deck slant
- Arrows rt left center
- Shift up down, go stop
- Calibrate
Dorm room swarm motion capture https://m.youtube.com/watch?v=0ql20JKrscQ&pp=ygUYRXNwMzIgZHJvbmUgc3dhcm0gdmlzaW9u
Diy drone https://th.aliexpress.com/item/32776829828.html?gatewayAdapt=glo2tha
Pull-up resistor project https://m.youtube.com/shorts/y_QIEyC-uUk
Calculate turning radius and use this to plot destination point to the right or left of the cone
- Max steering angle 27°
- wheelbase WB = 12.5cm
- Turning radius TR = WB/tan(a)
- TR = 125mm / tan(27)
- TR = 125mm / 0.509525449
- TR = 245mm
Make chart of deck angle to rudder angle
Find equation or interpolation
Interpolate table of deck tilt to steering angle then check a deck tilt of half.
- Max deck tilt 18°
- Max steering angle 27°
| resting helm angle | deck tilt | steering angle | circumference | |
|---|---|---|---|---|
| 0 | 0 | 0 | amidships | |
| 4.5 | 6.75 | 1/4 | ||
| 9 | 13.5 | 1/2 | ||
| 13.5 | 20.25 | 3/4 | ||
| 18 | 27 | full |
steering angle = comparison of front and back wheels
- the pair of right wheels and the pair of left wheels will have the same angle
- steering angle = rudder angle = wheel angle
Throttle adjustment
Develop direct ratio for rudder to right wheel throttle.
- Consider turning radius and circumference of each wheel.
- develop ratios for both right and left wheels
- In future, we might use two motors
radius = 245mm circumference = 245 * pi = 769.7
axle width = right wheel TR left wheel circumference
speed differential for each wheel depending on deck tilt
PID
A type of controller.
Develop PID for helm to rudder
IMU
Implement IMU on sk8 to get deck roll angle
- Digital motion processor (DMP), included on the mpu 6050.
What is a DMP?
- gyros have Lots of fluctuation
- even when sitting motionless on the floor
- Noise in the data
- Smoothing or Averaging
- Fusion algorithms: of data from multiple sensors: gyroscope and accelerometers
Inertial navigation system
Kalman filter
When stationary, every object is experiencing 1G of downward Force.
TODO
make a map of yellow cones, center points
x cover motor with tape
make another photo set
write python code to:
find the wheels, center points calc the centerpoint and angle of the sk8 (two choices) weight target, centerpoint calc the vector of the sk8, ie, change angle to vector (one choice)
convert python code to c++ and install on awacs
implement esp now to send coordinates from awacs to sk8
write code on sk8 to plot course (taken from previously written python program)
write code to
find yellow cones make a list of coordinates send changes from awacs to sk8
find earlier python code for plotting course
wheels black 0d0e06, threshhold 5
cones yellow bcb44f b7b159 9b925b
Azimuthal projection with minimum interruption
https://en.m.wikipedia.org/wiki/Interruption_(map_projection)
pilot
Arduino IDE settings:
- Board: Arduino Nano ESP32
- Port: ttyACM0
IMU
MPU6050
IMU AHRS
Quiic cable
| i2c | quiic | arduino | sk8mini |
|---|---|---|---|
| scl | yellow | A4 | blue |
| sda | blue | A5 | green |
AWACS
ESP32-CAM, by Espressif and AI Thinker
Best source of info: https://github.com/espressif/esp32-camera
Arduino IDE settings:
- Board: AI Thinker ESP32-CAM
- Port: ttyUSB0
Isolate minimal code to
- return Jason from url get
- set camera settings'
- return image from camera
Is it possible to edit EXIF header?B
3 lenses: 60, 120, 160 degrees fov wide
photo folders:
- ~/sk8mini/awacs/photos/60/
- ~/sk8mini/awacs/photos/120/
- ~/sk8mini/awacs/photos/160/
webapps/robots/robots/sk8mini/awacs/cam.ino
- empty setup() and loop() methods
- not used
robots/sk8mini/awacs/example/CameraWebServer/CameraWebServer.ino
- modified to connect to wifi as access point
- connected as station: slow
- connected as access point: less slow
- implement webserver commands
- /index.html
- /capture
- :81/stream
cam.py
- connect to the wifi
- call the webserver on the awacs
- use the esp32-cam “capture” command
- receive the returned image
- save it to hard disk
two decisions:
- framesize
- lens
- fov
- distortion
- clarity
- color
Lens Comparison
ov2640
longlens
label: DCX 2640 V2
fov: 120 degrees
long lens
maximum fish-eye type of distortion
filename: d_longlens_svga_8.jpg




