matto
10 µW
Hello everyone! I'm new here and this is my first post.
I love the Onewheel (https://onewheel.com/) but U$D 1500 is out of my budget (specially considering the U$D 300 for the shipping to Europe). I enjoy making things, so I decided to build one myself. The thing is that this involves learning a LOT of (new for me) stuff. I’ve been looking all over the internet, and I’ve found that some people has already made some successfully: http://wackyboards.blogspot.com.es/search/label/motorized self balancing
I didn’t know where to start or who to ask, until I landed here. It’s like the holy grail of knowledge for these matters.
I’ve worked with ESCs, brushless motors and LiPo batteries when making a quadcopter, but as far as I’ve seen this is in a completely different level given the torque and currents needed for it to move a person.
I’ll begin with what I already know:
My idea is to keep it as simple as possible. I’ll use Arduino with a Gyroscope / Accelerometer IMU to get the position of the board and move the wheel in that direction. The wheel is going to be a gokart rear wheel, just like the original board. The structure is probably going to be two solid aluminium bars to hold the wheel hub. The upper covers might be made of wood just like the original (not sure about this yet).
So far so good, but I have some questions and I would appreciate ANY help very much:
1) The motor
I’ve been reading quite a bit and it looks like it has to be brushless and sensored. At first I though about using an e-bike motor just because it would make things easier. It already has the hub, the hall sensors and a planetary gear system inside. It’s also made for having good torque at low revs. The bad part is that I should find one that fits inside the wheel rim, and that does not exist.
The guys at onewheel make their own motors, and they look awesome, but I haven’t found one that fits my wheel. I found a guy who successfully implemented an e-bike motor in one of these boards (http://www.transistor-man.com/flying_nimbus.html), but he went through a lot of trouble doing it, and he had water jet cutters and a lathe, tools that I don't have access to. Also, at some point the plastic gears died and he had to machine new metal ones. All of this does not add up to the "keep it simple" I'm looking for.
So what I plan to do is something like the original onwheel, but on it's early stages: A chain that goes to an external motor. Something like this:
Or even better, with the chain on the inside like this:
This would also allow me to choose the gearing ratio instead of being forced to use the one inside the e-bike motor.
Now here is the part where I need your help: I've been trying to decide which motor should I use. I've read that the lower Kv, the more torque on low revs but less final speed. I think that is what I need since what I really want is a lot of torque on low revs so the board can take me trough slopes easily. The final speed is important to me, but I don't need it to reach 45 mph. I prefer torque over speed for this particular board.
I found these two cuties on Hobbyking:
http://www.hobbyking.com/hobbyking/store/__5142__Turnigy_80_100_B_130Kv_Brushless_Outrunner_eq_70_55_.html
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=36656
The first being the one I like the most, but it's out of stock. In the comments a lot of people claims that they have used these to successfully make quite powerful bikes, mopeds, and even a boat that moves 2 people!
None of these motors have hall effect sensors, and what I've read is that having them allows the motor to have a way smoother start on low revs, and that's exactly what I want. So that leaves me with two choices: Find a motor with similar specs, but that includes sensors or just add external sensors.
Do you think one of these is the correct choice for this project? If you don't, can you tell me which motor would you use and where to buy it?
2) The brakes
Another thing I want to replicate from the original onewheel is the brake. You can see in the promotional videos that when the rider goes down a slope, they can actually brake and go down slowly.
How can I do this? I've been reading about regenerative braking, but maybe it's even easier and all I have to do is to invert the direction of the motor and the more power I apply in the opposite direction, the more it will brake. Is this possible or just a thing in my mind? If it's not possible to do it this way, how could I do it?
3) The ESC
I've read in this same forum that RC ESCs are not the best choice for personal mobility vehicles because they are simply not made for that. I saw people recommending to use e-bike ESCs for a range of reasons and I see the logic behind that. Specially because they are prepared for sensored motors and to deliver full torque at all speeds.
Can you recommend me which e-bike ESC should I use for this project and where to buy it?
4) The batteries
I'm almost sure that I want to use LiPo batteries because of the capability they have to deliver big pikes of current if needed, for example, to sort a slope.
But I've also seen a lot of people using Lead Acid batteries or building clusters of LiFe cells.
Would you recommend me to stick with the LiPos or is there a better alternative?
5) The gearing
I've actually not read anything about this yet, but if you have any information of which ratio would be good for this project, it will be widely welcome.
So that's it. Sorry for the long post!
I know I'm asking way too much. Specially being the new kid on the neighbourhood, but I'm pretty excited with this idea, and I'm sure that with your wisdom I'll be able to make it real. ANY tip you can give me on any of these points will help me a lot.
I promise to post detailed updates of the project in this post as it grows up.
Thank you!
I love the Onewheel (https://onewheel.com/) but U$D 1500 is out of my budget (specially considering the U$D 300 for the shipping to Europe). I enjoy making things, so I decided to build one myself. The thing is that this involves learning a LOT of (new for me) stuff. I’ve been looking all over the internet, and I’ve found that some people has already made some successfully: http://wackyboards.blogspot.com.es/search/label/motorized self balancing
I didn’t know where to start or who to ask, until I landed here. It’s like the holy grail of knowledge for these matters.
I’ve worked with ESCs, brushless motors and LiPo batteries when making a quadcopter, but as far as I’ve seen this is in a completely different level given the torque and currents needed for it to move a person.
I’ll begin with what I already know:
My idea is to keep it as simple as possible. I’ll use Arduino with a Gyroscope / Accelerometer IMU to get the position of the board and move the wheel in that direction. The wheel is going to be a gokart rear wheel, just like the original board. The structure is probably going to be two solid aluminium bars to hold the wheel hub. The upper covers might be made of wood just like the original (not sure about this yet).
So far so good, but I have some questions and I would appreciate ANY help very much:
1) The motor
I’ve been reading quite a bit and it looks like it has to be brushless and sensored. At first I though about using an e-bike motor just because it would make things easier. It already has the hub, the hall sensors and a planetary gear system inside. It’s also made for having good torque at low revs. The bad part is that I should find one that fits inside the wheel rim, and that does not exist.
The guys at onewheel make their own motors, and they look awesome, but I haven’t found one that fits my wheel. I found a guy who successfully implemented an e-bike motor in one of these boards (http://www.transistor-man.com/flying_nimbus.html), but he went through a lot of trouble doing it, and he had water jet cutters and a lathe, tools that I don't have access to. Also, at some point the plastic gears died and he had to machine new metal ones. All of this does not add up to the "keep it simple" I'm looking for.
So what I plan to do is something like the original onwheel, but on it's early stages: A chain that goes to an external motor. Something like this:
Or even better, with the chain on the inside like this:
This would also allow me to choose the gearing ratio instead of being forced to use the one inside the e-bike motor.
Now here is the part where I need your help: I've been trying to decide which motor should I use. I've read that the lower Kv, the more torque on low revs but less final speed. I think that is what I need since what I really want is a lot of torque on low revs so the board can take me trough slopes easily. The final speed is important to me, but I don't need it to reach 45 mph. I prefer torque over speed for this particular board.
I found these two cuties on Hobbyking:
http://www.hobbyking.com/hobbyking/store/__5142__Turnigy_80_100_B_130Kv_Brushless_Outrunner_eq_70_55_.html
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=36656
The first being the one I like the most, but it's out of stock. In the comments a lot of people claims that they have used these to successfully make quite powerful bikes, mopeds, and even a boat that moves 2 people!
None of these motors have hall effect sensors, and what I've read is that having them allows the motor to have a way smoother start on low revs, and that's exactly what I want. So that leaves me with two choices: Find a motor with similar specs, but that includes sensors or just add external sensors.
Do you think one of these is the correct choice for this project? If you don't, can you tell me which motor would you use and where to buy it?
2) The brakes
Another thing I want to replicate from the original onewheel is the brake. You can see in the promotional videos that when the rider goes down a slope, they can actually brake and go down slowly.
How can I do this? I've been reading about regenerative braking, but maybe it's even easier and all I have to do is to invert the direction of the motor and the more power I apply in the opposite direction, the more it will brake. Is this possible or just a thing in my mind? If it's not possible to do it this way, how could I do it?
3) The ESC
I've read in this same forum that RC ESCs are not the best choice for personal mobility vehicles because they are simply not made for that. I saw people recommending to use e-bike ESCs for a range of reasons and I see the logic behind that. Specially because they are prepared for sensored motors and to deliver full torque at all speeds.
Can you recommend me which e-bike ESC should I use for this project and where to buy it?
4) The batteries
I'm almost sure that I want to use LiPo batteries because of the capability they have to deliver big pikes of current if needed, for example, to sort a slope.
But I've also seen a lot of people using Lead Acid batteries or building clusters of LiFe cells.
Would you recommend me to stick with the LiPos or is there a better alternative?
5) The gearing
I've actually not read anything about this yet, but if you have any information of which ratio would be good for this project, it will be widely welcome.
So that's it. Sorry for the long post!
I know I'm asking way too much. Specially being the new kid on the neighbourhood, but I'm pretty excited with this idea, and I'm sure that with your wisdom I'll be able to make it real. ANY tip you can give me on any of these points will help me a lot.
I promise to post detailed updates of the project in this post as it grows up.
Thank you!
