- Software
- SolidWorksPrusaSlicerArduino IDE
- Production
- 3D printing · Original Prusa MK4S
- Course
- ZPC, BUT FME · 2024
- Role
- Whole product by myself — design, mechanics, electronics, software
Introduction
AxisCore came out of the ZPC course at BUT, based on the MIT How to Make (Almost) Anything course. The brief was open: come up with my own product, design it, print it, test it and present it.
I chose a three-axis phone gimbal because it combines everything at once: mechanics, electronics and programming. Until then I knew Arduino and servo motors, and not much more.
The original plan was based on a Storm32 control board and three brushless motors. They are not commonly available in the Czech Republic, so I picked brands with good reviews and ordered them from AliExpress.
The brushless motors turned out to be a completely different level from servos. I burned two Storm32 boards, and I could not even calibrate the motors; they barely started. I never found the cause. For a first project it was too big a jump.
The second board burned out a week before the deadline. I went back to servo motors and redesigned the whole concept around them. There was no time for a full redesign, so I sacrificed the X axis, which tilts the phone up and down.
How it came about
01 Desk stabiliser
First design
The first idea was for a desk. A phone or camera sits on a telescopic shaft, which is turned and extended by a worm gear. Two motors, an Arduino with a gyroscope, a joystick and a reset button are hidden in the box underneath.
02 Tripod for the field
Second design
Then I tried a tripod. The motors and electronics sit in a box between the legs; each leg has a threaded shaft with a guide groove and a joint with a foot, so the tripod adapts to uneven ground. It is controlled by a separate controller.
03 Handheld gimbal
Third design
In the end, a classic handheld gimbal. A motor in the handle turns the whole arms, two motors by the phone tilt and turn it, and the gyroscope sits by the phone. The handle has a joystick and two buttons. I modelled this design in SolidWorks and built it.
Parts
Gallery
01Second arm prototype with brushless motors and a Storm32 board
02First arm prototype
03Printing parts on the Original Prusa MK4S
04Handle made of two printed parts
In motion
Result
The gimbal worked: it rotated the whole arms around the Y axis, turned the phone between portrait and landscape, and the Home button returned it to the starting position. The phone is held by MagSafe. I tried it with an original iPhone and with a Samsung in a third-party MagSafe case, and both phones held and rotated without problems. It had no third axis and no gyroscope, so it did not stabilise on its own; it was controlled with a joystick.
The committee still rated the project as very ambitious and successful. What I'm most glad about is that I managed to redesign the whole concept in a week and bring it to a working state.
Where it’s heading
I plan a version 2.0: a rechargeable battery, stronger servos, a gyroscope, simpler and faster controls with better response, and a folding structure. I haven't got to it yet.
Specifications
- axes built / designed
- burned Storm32 boards
- week to redesign the concept
- sketched concepts
- Axes
- 2 of 3 designed (Y rotation, Z portrait / landscape)
- Drive
- Servo motors (originally 3× brushless GBM2804)
- Control
- Arduino Nano (originally Storm32)
- Mount
- MagSafe (iPhone and Samsung in MagSafe case)
- Controls
- Joystick and Home button
- Gyroscope
- No, ran out of time
What I learned
01
Brushless motors and Storm32
I went into an area I didn't understand. Two boards burned out and the motors could not be calibrated. For a first project it was too big a jump.
02
New concept in a week
After the second burned board I had a week until the deadline. I went back to servo motors and sacrificed one axis so the product could work as a whole.
03
Gyroscope didn't fit in the time
I wouldn't have got gyroscope stabilisation into decent shape in the time available. So I handed in a joystick-controlled gimbal that worked reliably.