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Forum: µC & Digital Electronics introducing my project "kicksurfer"


Author: Frank (Guest)
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I have been working on this during the last two years by now, and it is 
time to stop hiding in a cabinet.

It all started some years ago when I was commuting to work, and realized 
that my trip consisted of 20 minutes in a regional train, plus 10 
minutes walking to get there from home, plus another 15 minutes from the 
train station to my work place. In total that was 50 minutes of walking 
every day. Buying a foldable bike was an option then, but they are quite 
heavy and bulky especially when you have to lift them on a stairway. A 
colleague recommended me to use a kick scooter, they are very light 
(down to 6kg) and foldable. Said and done, but after some time using it 
each and every day, my hips and knees started hurting more and more. I 
realized that this kind of exercise was good for my condition, but not 
for my bones. Next natural step: electrification of my scooter.

As I am not a construction engineer, I decided to use an existing kick 
scooter model and upgrade it. My choice fell to this one:

OXELO Town XL susp
https://www.decathlon.de/city-roller-scooter-town-...

With 100€ it is a bit pricey, but I it is very well designed and doesn't 
all apart after the first few 100 kilometers. It is fully suspended and 
it has a stable folding mechanism. It also has lowered board, which 
reduces the required leg work during riding.

Because this is a quite popular model, there are almost identical 
Chinese copies of it, you can find them on ebay. They sell for roughly 
half the price.

At the beginning I developed my electric conversion kit just for my 
private fun and use. I have been using the prototype model for more than 
a year now, and the first battery is still alive after countless 
kilometers. And I realized that it would be the same fun each and every 
time that I step on it for a ride, that feeling does not seem to 
degrade. I get a lot of interest and positive feedback from people 
almost every time I come to a stop. All this helped me make my decision: 
make this a commercial product, and sell it to other enthusiasts.

That was when the kicksurfer project started. It was clear from the 
beginning that it would be a conversion kit for DIY'ers. It should be as 
simple to build as possible, and the price should be as low as possible. 
And, most importantly, it should be as convenient as possible.

As simple as possible: apart from the scooter and the kit, you only need 
a cordless screwdriver, a set of metal drills, a ruler (if available: 
caliper), and a hacksaw (if available: multifunction rotary tool). Build 
time should be less than two hours, but that is yet to determined.

As cheap as possible: targeted kit retail price (per lot of 100 kits) is 
449 euros. This includes everything you need: motor, battery, 
controller, charger, all construction parts.

As convenient as possible:
- smart: no levers, no handles - the controller senses the driver's 
actions and reacts on that
- standard mode: the driver kicks once, then the system permanently 
maintains the resulting speed - kick once, surf home
- street-legal mode for Germany: works like a Pedelec by only boosting 
each and every foot kick from the driver
- automatic brake detection: keeps down torque during braking and 
maintains speed thereafter
- automatic startup and shutdown: no power switch
- safe: driver detection ensures automatic torque cutoff when the driver 
steps off the scooter
- intuitive: feels exactly like a regular kick scooter, but with any 
friction removed
- speed: 2 to 20 km/h
- range: 10km (to be verified)
- charging time: 1.5 hours
- weight: 8kg

As of today, most parts of the kit are ready but there is some remaining 
work and money that I have to invest:
- battery pack transport test per UN38.3
- plastic injection mold tool for battery/controller housing, currently 
it is a 3D printed part - much too costly
- find and evaluate a suitable and safe charger, current model has CE 
mark on it but that is in fact [i]China Export[/i] - currently 
negotiations with two different manufacturers
- create mass test tool for controller board (needle bed adapter)
- add missing firmware features like configuration and firmware update 
via Bluetooth
- create PC / smart phone apps
- create step-by-step construction guide
- draw public attention and get funding for first mass production lot

Most recently I have set up a website for the project:

https://www.kicksurfer.de

It has just started and and I have to apologize that the main page is 
still empty. Both account management and blog system are running. If you 
are interested in this project, I would be happy if you would sign in 
for updates - I will regularly post updates in the blog section: 
https://www.kicksurfer.de/index.php/blog/

Latest post:
https://www.kicksurfer.de/index.php/2017/03/25/boa...

Author: Lockmann (Guest)
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It's a joke, isn't it? Who on mother earth will pay 449 Euro for next to 
nothing? What do I do with 100 kits? Feed them to the dog?

: Restored by Moderator
Author: Frank (Guest)
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Lockmann wrote:
> It's a joke, isn't it? Who on mother earth will pay 449 Euro for
> next to
> nothing? What do I do with 100 kits? Feed them to the dog?

That is the price per one kit, calculated from a production lot of 100 
kits. But what do you mean by next to nothing? You get a set of battery, 
motor (brushless hub motor with attached tire), controller, charger, and 
mechanical parts. Of course I need to include something for my fixed 
cost here, just UN battery test plus injection mold tool is 
>10,000euros. I don't expect to make any money from the first 100' lot.

Author: Codix (Guest)
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As your states: Nothing is ready to sell.
I think that this forum is the wrong place to offer your good.

Author: Frank (Guest)
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Codix wrote:
> As your states: Nothing is ready to sell.
> I think that this forum is the wrong place to offer your good.

I was posting it to introduce my work, and to receive feedback and your 
thoughts about it, maybe recommendations. I didn't expect this kind of 
reaction.

Author: Axel (Guest)
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what's the Maximum power Ratings of the driven Motor? Wich Controller do 
you intend to use?

---

Oh. there is no Motor, sry about this...

Author: Frank (Guest)
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Axel wrote:
> what's the Maximum power Ratings of the driven Motor? Wich
> Controller do
> you intend to use?
>
> ---
>
> Oh. there is no Motor, sry about this...

The kit will contain an 8'' 350W hub motor with integrated tyre. It 
directly replaces the rear wheel and is slim enough to fit into the 
wing.

The controller is a custom development, have a look at my blog. It 
allows torque control and the firmware runs FOC which improves 
efficiency and makes the vehicle very silent. I am thinking of making it 
open source hardware, but making the firmware open source as well 
requires some substantial work that I would need help with. Currently 
the controller is manually adapted to a specific motor.

Author: Feldstecher (Guest)
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Any pictures?

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