3D Printed Electric Longboard

Hello everyone!

As I prepare to attend college next semester I, like many others, have seen the appeal of electric longboards like Boosted Board as a practical, environmentally friendly, and simply awesome electric vehicle. I don't have $1500 dollars to spend on one of these vehicles, but that wasn't really the reason I wanted to build my own. I decided to build my own because I would not be able to stand not being allowed or able to repair the device I had saved for months to purchase. I'm sure many others feel this way as well.

So I began to explore what it would take to build my own electric longboard, and honestly I was rather disappointed. There were so many awesome guides for many high power or low cost longboards. The problem was, the technical requirements of making even the simplest of these vehicles were far outside of access to equipment. All other guides expect you to use a welder, CNC machine, or even a fully stocked machine shop. I don't even have access to a drill press.

As I explored other methods I began to realize I was not alone. There are many people out there who wish to make their own electric vehicle but don't have easy access to the skills or equipment so many of these tutorials require. The solution to me was obviously 3D printing. The power of 3D printing allows anyone to create complex components extremely easily. All that I had to do was create a 3D printable version of all the components people are struggling to manufacture and it would reduce the skill level required to create one of these vehicles significantly.

However, like I said, I wanted a longboard equivalent to the highest quality commercial versions. The internet is filled with budget longboard builds, this is not one of those builds. The most important spec to me was torque. I needed to be able to climb hills, as Cornell's campus is essentially on the side of a mountain.

Therefore the final specs are:



• Max speed: 20 mph
• Range: 14 kilometers
• Hill Grade: greater than 18% (steepest hill I could find)
• Weight: 14.5 pounds


Features:



• Safe Fast Charging (Full charge in one hour)
• Lights!
• Braking
• Waterproof

sorry guys. I was checking up on this instructable, and it appears as if instructables has removed all of my hyperlinks. Ill fix this when I have a chance.

3D Printed Components: https://drive.google.com/open?id=0B5OkSU2T21DVNTR...

Motor Mount:
• Motor Mount Top
• Motor Mount Top - opposite side
• 2x Motor Mount Bottom, mirror one
• 2x 14mm Spacers
Pullies and Wheel Hubs:
• 15ooth Pulley (must be nylon) or you can buy 15 Tooth Metal Pulley
• 38 Tooth PulleyMotor
• Wheel Inner Hub
• Wheel Outer Hub
Electronics Covers:
• 2x Battery Grip Front
• 2x Battery Grip Back
• Series To Parallel Cover
• Radio, BEC, and ESC Enclosure
Non-3D Printed Components:

Mechanical:
• Longboard
• 3/8in Threaded Rod Cut to: 3x6in, 1x7in, 1x5in 8x 3/8in Matching Locknuts
• 14x M4 Bolts, At Least 20mm Long
• 14X M4 Locknuts
• 6x 70mm Long M3 bolts
• 6x M3 Locknuts
• M3 Bolt 10mm
• M3 nut149kv Brushless Motor
• 2x LIPO Battery Protector
• 62 tooth belt

Electrical:
• 2x 5000mah 6 Cell LIPO Batteries
• 80 AMP Electronic Speed Controller (ESC)
• ESC Programing Card (Some say this is optional, they are wrong)
• Battery Elimination Circuit (bec)
• PWM Wires
• 12 AWG Wire Red and Black
• 4MM HXT Connectors

Charging:
• Battery Charger
• Power Supply
• Balance Connector

Lights:
• Arduino Nano
• 1M of 60 LED/M NeoPixel Strip

Controller Options:

Option One: Quanum Transmitter

Option Two: Wiiceiver Controller

Option Three: 3D Printed Controller (in progress)

• 2x XBee radios
• 2x XBee Adapters
• FTDI TTL Cable
• 10K Potentiometer
• 10K Resistor
• Large Push Button
• Small Push Button
• 8 LED NeoPixel Strip
• 350mah One Cell LIPO Battery

Tools and Equipment:
• Drill With Roughly 4mm Bit
• Basic Soldering Equipment
• Pliers
• Handsaw (to cut threaded rod)
• File
• 3D printer with at least 90mm^3 of build space

The most important consideration which so many overlook when building an electric longboard is the voltage of the batteries. The voltage is the factor which determines how fast a motor will spin but the torque is intrinsic to the motor itself. That means that the same motor will move twice as fast with a 12 cell battery bank as it would with a 6 cell battery bank, but with the exact same torque.

Despite this, most electric longboard builders completely overlook this fact and build 6 cell systems, mainly because it is cheaper. This is a huge mistake because while you may technically achieve the same max speed your torque, the factor that is the reason an electric longboard should exist in the first place, will be much, much weaker. Any longboard build which claims specs like "25 miles per hour and 20% hill grade" which are based on a 6 cell system are more than slightly over exaggerating. Because all components in an electric longboard must be built to the same voltage, there is no way to undo this mistake once the project has been started.

The longboard is powered by two 5000 miliamp hour 6 cell batteries wired in series to effectively achieve one 5000 miliamp hour 12 cell battery bank. The cell rating on a LIPO tells you the voltage it operates at. One cell has a maximum of 4.2 volts so the entire bank charges to a max of 50.4 volts.

This power is used to drive a 149kv brushless outrunner motor. The kv rating is essentially how fast a motor spins per volt. The rule of thumb is the lower the kv rating, the higher the torque of the motor. If you've seen other electric longboard builds you'll realize that this 149 kv rating is much lower usual. This is because most of those longboards operate on 6 cells and need the extra RPMs (and sacrifice torque to achieve it). Because this motor operates on 12 cells, it will move at virtually the same speed as a 300kv motor running on 6 cells but with FAR greater torque.

This section is the core of this project. When building an electric longboard, everyone agrees the most difficult part, by far, is creating a motor mount. There were, until now, only 3 options:



1. Buying a premade clamping mount: There are mounts sold online such as this one and this one however, once shipping is taken into account, both of them total more than 125 dollars on sale. That is a ridiculous amount of money especially since I've heard some very poor reviews and they don't look like they'd fit my motor.
2. Welding one: If you have the skills, equipment, and confidence that you can weld one of these $35 (+ s/h) motor mounts that is absolutely the path you should take. This guide is for those who do not.
3. Building your own clamping mount: There are multiple GREAT instructables and tutorials which detail the procedure to create your own clamping motor mount. The problem with these is they usually require a stocked machine shop and technical skills many people don't have. In fact, some of them require a full blown 50,000 cnc machine. So, while tutorials like those by Vulcaman (my German alter ego) are awesome, if I were to put the effort into gaining access to that machinery I would probably be able to just weld it.


If a motor mount existed that was cheap, easy to assemble, that anyone could use or even modify to fit their needs, it would decrease the level of technical knowledge and equipment to complete this project exponentially. That is the beauty of 3D printing. I can use what is my strongest capability, 3D modeling, to not only overcome my own technical limitations, but help others who are struggling with the same problem.

That's what makes this motor mount the focus of this project, creation of what appears to be the first 3D printed electric longboard motor mount, available to anyone.**

The final result is a zero flex adjustable motor mount which doesn't even require power tools to assemble, let alone a machine shop. Like I said in the previous slide this is one of the highest torque motors you will ever see on an electric longboard, and the mount will never flinch the slightest even under stall conditions. This is because this is also one of the only motor mounts which grips on to both sides of the trucks, adding a degree of support even a metal single sided mount couldn't match. It even has a plate positioned behind the motor which you could install a bearing if you wanted to make both wheels driven or simply add even more support to the motor, though I found this to be unnecessary.

Despite its strong performance, the best part about this mount is how easy and cheap it is to assemble. All it requires, other than a 3D printer, is a couple inches of threaded rod, some lock nuts, and a pair of pliers. All of that could be purchased for a few dollars and requires no technical skill to operate. Plus, it was all printed on a 100mm^3 Printrbot Play, one of the most basic 3D printer setups available. That means that nearly every printer could achieve the same results

**Since this project has been posted multiple other "3D printed electric long boards" have popped up, making this project a little less unique then it used to be. My design has had some obvious influences on some of them, which I am flattered by :)

The longboard I chose for this project is the Quest Super Cruiser. The one and only thing special about this longboard is the fact that it is the first result when you search the word "longboard" on Amazon. This was done intentionally, to show pretty much any typical longboard would work, even the most generic one. The only factor you really have to worry about is the height of the board of the ground, as some longboards with a lowered deck might have clearance issues. The longboard is also the biggest factor in deciding the weight of the vehicle and how it will feel while riding. Over all, just pick the longboard which fits you best.

Be aware of the shape of the longboard trucks to make sure its compatible with the motor mount, though it appears to be compatible with nearly all longboard trucks. They all appear to fit the same basic shape profile, 3 flat sides and a curved top. If you do happen to have a longboard you want to use, but my mount won't fit it, message me! The fact that this is a 3D printing project allows for an unparalleled level of collaborative design, even across huge distances. Plus, once we have a model that works for you, I can update this instructable to further help anyone else with the same issue.

In order to convert the high RPM of the motor to a reasonable speed you are going to need to gear it down. The size of the gears will change depending on various factors including the size of the wheels and what your needs from the longboard are. I personally chose to focus on torque with a gear ratio of 12 to 38, resulting in a top speed of 20mph.

The best way to calculate what gear ratio you will need is to use this Excel spread sheet:

https://drive.google.com/folderview?id=0B5OkSU2T21...

It will take into account all of your individual factors to allow you to pick what gear ratio is best for you. Once you know your gear ratio, you must calculate your belt size. To do that you can use this calculator https://sdp-si.com/eStore/CenterDistanceDesigner. This will ask you for your gear sizes and your "center to center" distance. This is the distance between the center of the pullies. For this motor mount the absolute minimum is 74mm. Aim for slightly above that when picking your belt size. Remember, the motor mount is adjustable, so going a tooth or two bigger won't hurt.

In order to attach the large pulley to the wheel you must drill six 4mm holes into one of your longboard wheels in a circle with a 32mm diameter. Take your time. You technically have four chances to get it right, but avoid that if you can. I personally mistakenly had all of my holes off by exactly 1.6 millimeters in the same direction. Instead of re-drilling the holes, I edited the pullies and the hubs and reprinted them. Oddly enough, it worked perfectly! Rapid prototyping to the rescue!

I also designed the "hubs" which fit into either side of the wheels. One of these would normally print with the large tooth pulley. By printing them separate it makes them MUCH easier to print and allows the pulley to be replaced without reprinting the entire thing. The entire thing is held together by six 70mm M3 bolts with locknuts.

To attach the small pulley to the motor you'll want to file down one side of the motor shaft. The 10mm M3 bolt and nut are used to hold it in place. This pulley can NOT be made of PLA. I posted a picture above of what will happen if you attempt to use a PLA version of this pulley. Either 3D print it in nylon or buy an equivalent pulley online. I used a nylon pulley initially, but after a few months of use and two replacements I simply purchased a metal pully from SPI. I recommend this as the safest course. If you do choose to go the nylon route make sure you dry the filament in a 200 degree Fahrenheit oven for a few hours. I've only had mine for a few weeks and kept it in an air proof box the entire time, yet I still struggled to get good bonding between layers until after I dried it. With something like this, where strength is a necessity, I would recommend freshly drying it.

All of these models are included in the "Final Models" folder of my google drive.

https://drive.google.com/open?id=0B5OkSU2T21DVNTRK...

The ESC I have chosen for this project is the VESC. I originally chose a different ESC for this project however after a month I noticed some braking inconsistencies which weren't adequate.

I am glad I made this switch. The capabilities of this esc are amazing. Not only does it have a lot of powerful features such as regenerative breaking, but the quality of the sensor-less speed detection is impeccable.

The configuration is pretty basic, just follow the guide posted blow.

http://www.electric-skateboard.builders/t/new-vesc-user-read-this-complete-walktrough-of-the-vesc/2980

The wiring for this longboard differs slightly from that of other electric longboards. That is because one of my requirements for this build is I wanted as few wires coming out of the longboard as possible while charging.

That is what the little black box with 5 terminals coming out of it is for. In the normal configuration where both batteries are on the lower level the system is in series. When you move the battery on the left from its lower position to the higher terminal it cuts power to the longboard and puts the two batteries in parallel. You can then plug your charger into the port on the top. You also must connect the two balance charge cords together using the Balance Connector, an annoyance I couldn't avoid.

This is optional and a luxury, but I believe its worth it. If you want to take this to the next level, you could try building a battery management system. This is essentially a board designed to maintain the correct voltage between all the cells, so you don't have to carry around a bulky balance charger to charge it. I personally was running low on budget as it is so I took the inexpensive route.

Using the charger I outlined in the parts section you should be able to safety output 10 amps to the entire system, charging it in roughly one hour. The power supply is not small but the charger itself could fit in your pocket. Over all, the system would not be difficult to fit in a backpack.

You'll also need to decide how you want to power your radio receiver. This is what the "BEC" or battery elimination circuit is for. Essentially, its a circuit that makes it so you don't need an extra battery to run your receiver. This was an absolute must for me as I am going for the whole "2 wire charging" thing and an entire separate battery would ruin that. You don't have to take that route and could simply buy a separate one cell battery if you wish.

You'll need something to hold your batteries and electronics in a way which will keep them stable and protected. Some custom-form their own box, others glue a piece of tupperware to their board. But this is a 3D printed vehicle build, why not 3D print the housings?

The only way to securely attach the electronics to the board is to drill into the longboard. Unfortunately this means you will need a drill for this step, and a 4mm drill bit.

Be very careful when you drill the holes, there is no going back. Luckily since the electronics hand on the bottom of the longboard, any mistakes you make won't be easily noticed.

9/6 this section is currently being updated to include more details.

Now that you've chosen all of your components, you're going to need a way to control the longboard! There are multiple premade radio transmitters on the market, my particular favorites being the Quanum controller for its price/ease of use and the Wii Nunchuck style controllers for their attractive design.

However, neither of these controllers really felt right to me. They were either two bulky, two hard to control, or just didn't scream electric longboard to me. But hey, I have a 3d printer and decent electronics experience! Why not make my own?

40 dollars latter I have a light and extremely power efficient (4+ hours of use) handheld controller which feels great. Its design is very similar to the Boosted Board controller with its top mounted thumb wheel. the design is simple, a small radio transceiver, an arduino nano, and a potentiometer. The code is in my master project folder, like evrything else.

This segment was going to be a multi-step, detailed tutorial on how to make water resistant enclosures and sealing cracks between the board and 3d printed parts.

That's until I found out that making rc electronics waterproof is actually super easy!

All you need is this stuff called CorrosionX! Its this spray which, through some weird chemical properties, binds to exposed metal and sticks to it, preventing it from making electrical contact with the minerals in water. This stuff is so great I was able to use bare NeoPixel strips on the bottom of the board.

This spray doesn't just make things water resistant. In most cases, it makes it waterproof. I don't have the guts to test it, but as you can see in the video embedded above a simple spray can make exposed electronics fully submersible. Far better waterproofing than an electric longboard would ever need.

Just spray everything from the light strips, to the esc, to the battery terminals. Because this stuff also acts as a lubricant, so its even a good idea to spray the longboard's wheel bearings. The actual application is really that simple, though I included a video by FlightTest above, mainly because I found it to be entertaining.

That all being said, rain is a longboarder's worst enemy. I have not experienced it myself but I have heard that a longboard is extremely difficult to ride in the rain. This guide intended to remove your fear of puddles, not to allow you to ride in a thunderstorm.

The lights for this project are more than just to get a good thumbnail (though they totally do). One of the biggest complaints I've seen from commercial electric longboard owners is how because there are no built in lights its absolutely terrifying to ride in the dark. Multiple times I have seen guides where people will take stick on bulbs and put them on the bottom of their longboard for exactly this reason. Given we are building own own longboard, I think we can do better than this.

The lights for this project are one meter of black NeoPixel strips. They are controlled by an arduino nano which is connected and powered by the radio receiver. The wiring for these lights is extremely simple. Just connect their power and ground lines to the power and ground lines of the arduino. Then, connect their "data in" lines to any of the digital ports on the arduino, I did pins 2 and 5.

The code which controls these lights is in the following folder:

https://drive.google.com/folderview?id=0B5OkSU2T21DVOEpmZVhJekZ3MlE&usp=sharing

Every PLA 3D printed Part for this project was created using the following settings on a PrintrBot Play:

Layer Height: 0.2065mm (Maximum Speed, lowest quality)

Shell Thickness: 1.2 mm

Bottom/Top Thickness: 1.2mm

Fill Density: 60%

Print Speed:60mm/s

Print Temperature: 208 Degrees

Support Type: Everywhere

Platform Adhesion type: Raft

The 12 tooth pulley, as I've said before, was printed in nylon. This print differed in too many individual ways to list. nylon is a very temperamental material, so it took a long time to find settings which work for it effectively.

In case you'd like to access my full 3D Printing profiles, I have attached a link here for you to download them here:

https://drive.google.com/folderview?id=0B5OkSU2T21...

Thanks!