jupitersky
1 µW
- Joined
- Sep 22, 2020
- Messages
- 2
I’m interested in converting a front wheelchair attachment that I have into an electric attachment. I have some questions with regards to the e-conversion process that I’d appreciate some help with.
The attachment lifts the front wheels (casters) off the ground slightly. This allows for much better all-terrain access, without needing to wheelie constantly or risking getting thrown off of the wheelchair when it comes to a sudden stop on rocks, uneven surfaces, etc. Here are a few images of the actual front wheelchair attachment that I am looking to make electric, in order to give you some context:
The why:
I have some neurological problems and am in need of a wheelchair due to a recent serious infection that attacked my nervous system. One of the problems is that I can’t go for long distances outside, as I get very tired very easily and am very weak. This is not that uncommon, and there are a few power assist devices (a motor that you attach to your chair) that help to propel it. Unfortunately, I’ve tried out the major market competitors and none of the solutions have quite worked for me. Plus they are super expensive and unreliable, with extremely poor warranty service, and after dropping 4K on a wheelchair and getting scammed out of a power wheelchair for 5k+, I’d rather build my own.
The plan:
I already have a front wheelchair attachment that lifts off my front casters, kinda turning it into a tricycle configuration. I’d like to do an e kit conversion to the wheel (in the style of a lot of the scooters or e-bikes out there). Basically I would be replacing part 104 on the diagram (see images below). This is a similar design to the little scooters that clip on to the front of a wheelchair, which works quite well, while being quite a bit more portable.
Eventually I would love to make this Bluetooth-powered with a python microcontroller, but for v. 1.0 I’ll focus on making everything wired.
There are two ways to do this:
1) Just replace the tyre with a hub motor tyre that fits the existing housing. Unfortunately, I haven’t found a commercially available hub motor that is the right dimensions. The two forks are 75 cm apart from each other, and the axle cannot extend past these points - everything I have found on aliexpress or similar is either too wide or has an axle that extends past the two forks.
This means that the best option is looking like:
2) Replacing the entire fork part, as well as adding in a hub motor, speed control, and battery. This means that I am replacing and machining the fork (P005) and the tyre (P035).
I have ordered the following parts on AliExpress:
- Kit, includes 12-inch hub motor with tire, BLDC controller, and thumb throttle with LCD display (36V 350W motor) - https://www.aliexpress.com/item/4000169008204.html?spm=a2g0s.9042311.0.0.5bc74c4dU6GiuP
- Battery, water bottle style, 36V, 14Ah Samsung. Can be charged via USB
https://www.aliexpress.com/item/4001359961031.html?spm=a2g0o.cart.0.0.777d3c00lZU97E&mp=1
My questions are as follows:
Questions:
- How do I connect the battery to the speed control and hub motor? What sort of cables do you recommend? How do I make sure that the cables that I choose are at least somewhat waterproof?
- How do I connect the other parts of the speed control? 2 battery leads should go to the battery, 3 motor phase should go to the hub motor, display should go to the LCD display, what about the remaining connections? What do I connect the PAS sensor, brake, and hall to? Do I need to plug in the wires labeled ‘light, horn, USB power wire’?
- Is it worth it to do the 14Ah battery over the 11.6Ah battery? How much range do you find that you get roughly from one vs. the other?
- Do I need anything else in order to make this work in addition to the battery and cables?
- Pros and cons of a water bottle style vs a rack style battery? This specific battery seems straightforward to charge and has a nice battery level indicator, so that seems great, but anything I could be missing out on by not using a rack style one?
To give you a little more detail about my background, in case that is helpful to know when trying to explain things: I know how to solder and am quite technical, though my experience is primarily with software rather than hardware.
And then with regards to machining the actual fork part:
- I believe this part was made by cutting it down using something like a water jet and then welding the parts together. For a prototype, I believe that I’d try to 3D print the part. Ultimately, the final part should be quite durable. What is the best way to get this part machined/made? I used to have access to a machine shop, and have used a water jet and laser cutter, so have some experience with this kind of thing, but no longer have access to a shop and have quite a few physical problems that would keep me from machining the part myself. What would you recommend as the best way to get this part done on demand? What would be the best machining technique, both for a prototype and for a final product?
- How do I make sure that my parts will fit together, apart from just careful measurements with calipers?
And finally, the CAD of the hub motor I am getting in case that is helpful:
The attachment lifts the front wheels (casters) off the ground slightly. This allows for much better all-terrain access, without needing to wheelie constantly or risking getting thrown off of the wheelchair when it comes to a sudden stop on rocks, uneven surfaces, etc. Here are a few images of the actual front wheelchair attachment that I am looking to make electric, in order to give you some context:
The why:
I have some neurological problems and am in need of a wheelchair due to a recent serious infection that attacked my nervous system. One of the problems is that I can’t go for long distances outside, as I get very tired very easily and am very weak. This is not that uncommon, and there are a few power assist devices (a motor that you attach to your chair) that help to propel it. Unfortunately, I’ve tried out the major market competitors and none of the solutions have quite worked for me. Plus they are super expensive and unreliable, with extremely poor warranty service, and after dropping 4K on a wheelchair and getting scammed out of a power wheelchair for 5k+, I’d rather build my own.
The plan:
I already have a front wheelchair attachment that lifts off my front casters, kinda turning it into a tricycle configuration. I’d like to do an e kit conversion to the wheel (in the style of a lot of the scooters or e-bikes out there). Basically I would be replacing part 104 on the diagram (see images below). This is a similar design to the little scooters that clip on to the front of a wheelchair, which works quite well, while being quite a bit more portable.
Eventually I would love to make this Bluetooth-powered with a python microcontroller, but for v. 1.0 I’ll focus on making everything wired.
There are two ways to do this:
1) Just replace the tyre with a hub motor tyre that fits the existing housing. Unfortunately, I haven’t found a commercially available hub motor that is the right dimensions. The two forks are 75 cm apart from each other, and the axle cannot extend past these points - everything I have found on aliexpress or similar is either too wide or has an axle that extends past the two forks.
This means that the best option is looking like:
2) Replacing the entire fork part, as well as adding in a hub motor, speed control, and battery. This means that I am replacing and machining the fork (P005) and the tyre (P035).
I have ordered the following parts on AliExpress:
- Kit, includes 12-inch hub motor with tire, BLDC controller, and thumb throttle with LCD display (36V 350W motor) - https://www.aliexpress.com/item/4000169008204.html?spm=a2g0s.9042311.0.0.5bc74c4dU6GiuP
- Battery, water bottle style, 36V, 14Ah Samsung. Can be charged via USB
https://www.aliexpress.com/item/4001359961031.html?spm=a2g0o.cart.0.0.777d3c00lZU97E&mp=1
My questions are as follows:
Questions:
- How do I connect the battery to the speed control and hub motor? What sort of cables do you recommend? How do I make sure that the cables that I choose are at least somewhat waterproof?
- How do I connect the other parts of the speed control? 2 battery leads should go to the battery, 3 motor phase should go to the hub motor, display should go to the LCD display, what about the remaining connections? What do I connect the PAS sensor, brake, and hall to? Do I need to plug in the wires labeled ‘light, horn, USB power wire’?
- Is it worth it to do the 14Ah battery over the 11.6Ah battery? How much range do you find that you get roughly from one vs. the other?
- Do I need anything else in order to make this work in addition to the battery and cables?
- Pros and cons of a water bottle style vs a rack style battery? This specific battery seems straightforward to charge and has a nice battery level indicator, so that seems great, but anything I could be missing out on by not using a rack style one?
To give you a little more detail about my background, in case that is helpful to know when trying to explain things: I know how to solder and am quite technical, though my experience is primarily with software rather than hardware.
And then with regards to machining the actual fork part:
- I believe this part was made by cutting it down using something like a water jet and then welding the parts together. For a prototype, I believe that I’d try to 3D print the part. Ultimately, the final part should be quite durable. What is the best way to get this part machined/made? I used to have access to a machine shop, and have used a water jet and laser cutter, so have some experience with this kind of thing, but no longer have access to a shop and have quite a few physical problems that would keep me from machining the part myself. What would you recommend as the best way to get this part done on demand? What would be the best machining technique, both for a prototype and for a final product?
- How do I make sure that my parts will fit together, apart from just careful measurements with calipers?
And finally, the CAD of the hub motor I am getting in case that is helpful:
