The E-Board Project: Episode IV

While Premiere Pro is rendering in the background I figured I would start writing already. First of all special thanks to my colleague and dear friend Mike who helped me a lot today with the Arduino and the brushless motor.

The mount for the belt wheel is still temporary but we wanted something to mess around with. So here is how it works. The lithium battery powers a brushless motor controller which is intended for I believe model airplanes. Since I don’t have an RF receiver communicating with controller to make the motor run I need something else. For prototyping I am using an Arduino UNO right now but that will be replaced by an Arduino Nano in the final build. Since the RF transmitter only uses a PWM signal do control the controller this was pretty easy (with the help of Mike ;-)).

I actually only wanted to test the motor today since I have never actually used it since I bought it. Mike however helped me to build a little test setup and well he did most of the coding. I am sure I could have done it myself but he is just way faster. I call him the Arduino whisperer ^^. Since I had camera siting right next to me I shot a few scenes and edited them really quick to give you a quick few of what we did. We also tried the motor with the drive shaft which worked pretty well. Only the motor mount is missing and we are ready for a testspin.

The E-Board Project: Episode III

So while I was gone over the weekend my new thread cutters came in the mail. I also got a wireless Nunchuck from Logic 3. This one is going to replace the wired one I am using for prototyping.

So long story short. I finished the first drive shaft. I am probably going to finish one side of the drive train first. That way I can make changes to the other side in case something shouldn't work as planed. Pretty much all that was left to do was to cut a thread on the shaft and make the washer, which is supposed to form a force fit with the wheele and the shaft.

  

Since there isn't really a lot of  area for the washer to press against inside the wheele I thought to myself. Why not increase the transmitable torque by adding a cylindrical press fit? I was in the shop so I didn't have anything to do the calculations with. I decided that 1/10 mm excess should work ok. I knew that that the bearings usually have aroung 5/100 mm and they sit pretty tight. So double that sounds good to me.

                                                  

 It turned out that 1/10 is quiet a bit when it comes to actually putting the part into place. I figured if I heat the wheele and cool the washer it might actually make difference. So I put the washer in the freezer for a few minutes which cooled the part to around -7°C and heated the wheel in hot water which was around 55°C. Who would have thought it would work... well actually it didn't. I had to use a hammer to get it in but oh well it was worth a try.

 Onve the washe was in there I only needed to add the nut an it was DONE! I need to get some M10 self securing washers though because I am too worried it will loosen.
I thought I would add a quick screen shot out of my CAD software for comparison. I think it turned out pretty good

The E-Board Project: Episode II

Another day another chalange. So here is a tiny little update from last nights work. I am almost finished with the drive shaft. The Flange connection is finished and it's working very well. So without many words, here are some pics of the current progress.

                 

The E-Board Project: Episode I

So today I actually got a little bit done after work. At first I would like to share some of the goals I set myself for this project.

With this project I want to build a board with wich I will actually commute between home work and my university. I also want to use this project to improve my electronics skills and also hopefully my manufacturing skills. Once this project is finished and all the bugs are ironed out I am planing on open sourcing all the plans so everbody who as acces to the right tools easily build their own E-board.

Right now I am planing to have around 1600 W of power. After a few calculations this should be more than enough for cruising and also going uphill. I want to get a range of at least 15 km out of the board and most importantly add as little weight as possible to the board. To enhance the range I am planing on implementing e regenrativ breaking system later on. The drive system will be universal. So it wont matter what kind of wheels or what kind of deck you want to use. Even regualr skate bearings can be used so you can mix it all up just how you like it. I might even build a kind of adapter system wich will work with at least more tha just this one truck.

So what kind of parts are going to be on board? Well I am going to be using Orangatang Durian wheels. I chose those mainly because of the rather big diameter of 75mm. This will allow for smoother and easier riding in town. We have a lot of cobblestone here so I hope riding over that wont be too bad.

 Since I wont be manufacturing my own trucks from scratch I am starting of with a pair of Caliber trucks. The somewhat square cross section will hopefully allow for easy motor mounting.

 

 The board will be powered by two brushless motors. Each of wich have around 800W of power. My first idea I had a few years back was to use hub motors on each wheel. However there arent really any motors that would fit my requirements. Building my own hub motor is kind of out of question at this point since I don't really know how. Maybe in a later version I will actually get around and try building my own motors. For now those Turnigy will do. 

In order to get the power to the wheels I am using a belt drive. Belt drives have a higher eficiency than chain or gear drives and dont need any lubricants.

To make sure the drive shaft is stable I am using SKF 608 bearings. As a mechanical engineer I realy only trust SKF or FAG bearings :-P.

In order to have some sort of throttle controle I am using a Wii Nunchuck right now for tests. I kinda want to design my own controler since all those wireless nunchucks out there aren't realy that pretty. Today I got an Logic3 wireless controler in the mail wich will be replacing the wired Nunchuck I used for tests before.

I haven't really decided on a deck yet. I kinda really want to try one from Bareknuckle Longboards but also want to build another deck myself. But thats one of the last parts I will be thinking about. One the drive chain is up and running I will be deciding on the overal design.

What is done so far:

Like I said I got a few things done today. I was working mostly on the drive shaft today. I am using a mill/lathe combo mashine we have at work. Following there are some pics going from the aluinum blanc tho the finished shaft. Well almost finished. I need to buy new thread cutter to cut a thred at the narrow end of the shaft. I also need to drill holes in order to flange the shaft to the belt wheel. I will add some more detailed pics of the finished belt wheel later.

The smal belt wheel next to the drive shaft is supposed to go on the motor. Since the motor shaft doen't provide anything to creat a tight fit I will have to improvise some and greate a  force fit. The cylincdircal press fit I made today doesnt work that well yet and isn't easy to mount. I will look into that once I finish the drive shaft. Probably will have to order new  belt wheels first though since this one is pretty much ruined now.

Still need to put a thread on the shaft once I get a new set of thread cuters. Also need to turn a smal  custome washer that goes where the bearing usually would sit.

 All put together and already mounted to the truck.Only the flange connection is missing.

 

 Belt wheel with 22 H7 bearing seat. There is one on ther other side that also serves as centering for the drive shaft.

 

So that's that for today. I probbably wont get around to work on the board till next week. Maybe a bit of arduino programming over the weekend. Oh and by the way. Everyone who thinks an E-board is just for lazy people... well I am lazy. But I also own and use a regular longboard ;-).

See you next time

Ppanda