Just to show the model
Link to where I bought it: https://www.fwheel.cc/Product-Self-Balancing-Electric-Unicycle/two-wheel-scooter-basic.html
It’s very easy, leave them a message and they will contact you in short time or talk with them telling about your needs online, then pay for it.
Power button back side.
4 wire cable is for the power button other is for the LED
The main circuit board and a motor controller.
The motor controllers control only the side motor each. They do communicate with each other because of the red-black-brown wire that goes from all the way on the right to the motors in the middle.
Explained a bit better in the next photo.
The inside of a wheel
This is where the motor is housed, now I have opened it up I think I can say it’s a 3 phase AC motor. Some of you may be thinking “why would you use an AC motor on a DC system?” This is because AC motors have greater control over their start up torque and are generally more efficient at higher power requirements.
The way you can tell it’s a 3 phase AC is because you have 3 separate relatively large wires connected directly to the main circuit board next to the DC-AC converters, and then a 6 wire phase controller which is nesacary for an accurate 3 phase AC motor.
Pressure Pad Module
No a great photo… Originally I thought this was a motor controller but upon further inspection decided that it was more likely some sort of logic board for the pressure pads.
The Main Microprocessor
It’s a ARM STM32F103 (specs for ya nerds: http://www.st.com/web/en/catalog/mmc/FM141/SC1169/SS1031) To put it into perspective it has similar specs to a commodore 64 (probably even better.) Remember that the motor controllers do a lot of the work in this device so it’s power doesn’t matter very much. It costs about $5 on Ebay right now.
Central motor assemble
I used to think that: “This picture shows the middle section of the device, and the main mechanism that keeps you balanced. The motors are hidden in the cylindrical metal housing on either side. I get the impression from he wiring/size that they use the same motors for the central rotation as well as for the main wheels.” However that is wrong. There are only 2 motors in the entire mini segway and they are located inside each wheel. The way it does keep balance is a physics effect called and Inverted pendulum, you can read some more about it here: https://en.wikipedia.org/wiki/Inverted_pendulum
The main reason I disassembled it is in this photo too. There is a small pin that is visible right in the middle, you can see it;s housing on either side. This pin is not attached to anything and is designed to ensure that the 2 sides don’t rotate away. It can slide into the opposite side and lock up which severely damages control and makes it quite dangerous. The way to fix it is to to just tilt it back into place. I may do a fix for this later, however it require more dis-assembly.
One of the central motors
Once again, not a great photo
Back of the Charging side
battery and a motor controller
Power also goe
And the moment you have all been waiting for…
Awww, looks like I have a Chinese battery. No Samsung for me. Nevertheless I am still impressed with the battery life. Really excellent Made in China battery.
A quick warning is that this battery is very large to travel with on US airplanes, meaning be careful fly with your mini segway! This battery is 144 watt hours. Make sure you do your research if you want to fly with it! Source: wattHours=voltage*ampHours; https://www.faa.gov/about/office_org/headquarters_offices/ash/ash_programs/hazmat/passenger_info/media/faa_airline_passengers_and_batteries.pdf
EDIT: Reddit user /u/fred28046 reports that he as taken it in carry on in a plane. I would still recommend caution when traveling by air.
Stopping battery wobble
I noticed that the battery was a bit loose and I didn’t like that so I found a piece of plexiglass and jammed it in to secure the battery…
A pressure sensor.
One of the pressure sensors. There is only 2 on each side and they appear to be lined up with the outermost edge of the pad above.
You can see it is linked via a small cable to the motor controller. Then it goes to the microprocessor on the motor controller after passing through some resistors and such.
Top plate removed
It could be unscrewed from the inside.
The rubber pads have metal bottoms to allow the weight to be distributed to the sensors even when you’re not directly on top of the sensors. The outer plastic shell secured the rubber on, once that was removed you could just take it off.
The entire Insides!
On the right you have the side which has the power button. This section houses the main circuit board and a motor. The left side has the battery and a motor controller. One thing I noticed is that there is a metal frame on the inside which explains why these things can take such a beating (although I still wouldn’t jump onto it.) Looks/feels like it’s made out of steel are aluminium, most likely aluminium.
Reassembled and it works!
Anyway this thing is too much fun and I am enjoying it a ton! Being able to do a tear down is an added bonus!
Related product: Self balancing scooter QQ1