Dual+ (2000W)gammaray wrote:Hey agraham, which Boosted Board do you own? There are three versions of the Boosted Boards (http://shop.boostedboards.com/collectio ... ted-boards) running 1000W, 1500W, and 2000W.agraham wrote: As requested here is a video. It's blurry and blown out because my phone sucks but it's Justin and Robbie on my Boosted and their weight sensing board in a drag race.
And indeed it was. Here's the whole 30+km commute loop: The lion's gate bridge is a tad nervewracking on a powerboard. The joints between the bridge segments are harsh on skateboard wheels, and the railing on the mid-section leaves a gap that unlike on the 2nd narrows bridge is large enough that the board could shoot right through it. So the risk of bailing and then watching the longboard roll overboard is a definite possibility Before I left in the morning I also reduced the CA data's averaging so that we could look a bit more closely at the signal dynamics on the board. The special skateboard CA firmware has an 11Hz data output rate, so it gives good time resolution of all the weight signals on the trucks while riding. In the CA trip analyzer program, the front weight shows up in the "H.RPM" column, and the rear weight is in the "H.Watts" column, purple and green lines respectively in the graph snipped below, every time there is a bump in the track you see these spike up to 200+ lb. http://www.ebikes.ca/tools/trip-analyze ... rip=zWNULAjustin_le wrote: Weather permitting I'll ride it again back to work in the morning, this time taking the spirit trail to the lions gate bridge and then riding through Stanley park and along the waterfront bike path back to the shop. Should be a thrilling way to start the day.
Oh I've been waiting for this moment for over a decade, it's all finally coming around full circle which is great. When we started the UBC ebike club in 2003/2004 about half the projects were electric boards, starting with the loaner ExKate that I started this thread with. Plus a few 3-wheeler board using small scooter hub motors. These were geared motors and couldn't do regen, so we had a cable actuated drum brake for slowing down: And then the balancing 2-wheeled "project emanual", which is definitely due for a 2015 build update If anyone's interested I saved most of the website we had for that and put it here:onloop wrote: ... may i ask what has focused your attention on the realm of eboards lately?
For some people for sure. I won't go so far as that as a generalization; the future for inner city transportation should include human sized EV's of all kinds. Boards for some, trikes for others, bikes for many, and giant self driving cars? BLAH, take that american idea of transportation utopia right back to the suburbs.....ebikes are so 2014... the future is eboards?
That's part of it too!My guess would be weather. First weeks of sunshine in the PNW.
justin_le wrote: If anyone's interested I saved most of the website we had for that and put it here:
Though all the original videos were hosted on the long gone google video.
That's actually been the most successful of eboards I've build so far in terms of years of continuous usage, build in 2006 for burning man, here it is at the 2008 car free festival (the remote in the hand is just for steering, there was something up with the differential lean sensors at the time): Upgraded the deck to use the ends of a snowboard rather than plywood to good effect and had it at the several Maker Fairs right up until 2012. The sharp snowboard edge did gouge a few shins so eventually I put a rubber bumper on the nose and tail:sk8norcal wrote: I don't remember seeing this one,
Not far off. Strain gauges are just resistors etched in a zig zag grid, and when the surface of the metal is under tension, it stretches, elongating and thinning the resistor wire causing its resistance to increase tinyest amount (<<1%). Similarly, when the metal surface is under compression, the resistive wire gets shorter and fatter, lowering its resistance by a fraction of a percent. It's one of the most deceptively simple and ridiculously accurate electromechanical sensor devices, but it does require a high precision low drift instrumentation amplifier to turn the bridge output into a 0-5V signal.onloop wrote: was i close?
Hope the Rojas work out for you. Can't wait to see this project mature.justin_le wrote:Last year Lone_Deranger mentioned the Rojas Hybrid trucks on this thread,
https://endless-sphere.com/forums/viewto ... 80#p904580
Yes of course. I've already experimented with this approach as a throttle for ebikes and Arlo built a very nice regen brake lever for a motorcycle; the lever is fixed but a strain gauge senses how hard you are squeezing and it works brilliant:onloop wrote: So here is my question, and of course this is that exact opposite of what you are building (skateboard without remote) , is it possible to make a wireless hand control with zero moving parts?
Yes and no. It would be much more reliable in the long term than a pot, which will inevitably develop wiper problems. But it's also way overkill for precision and accuracy than what you need in a hand squeeze sensitive throttle device. There are other ways to sense squeezing force that are more than adequate for a throttle and a lot cheaper for mass production. A flexure with a moving magnet and hall sensor is one common approach, and force sensitive resistors are really simple to use for this kind of thing too.Would it make sense to replace a potentiometer with strain gauges?
Then don't wait for it to happen, go out and build one!It would make for a really cool looking remote.
Clearly your plan is to make a kit that people can buy and combine with some Rojas trucks. Are you thinking an in-wheel motor kit or a weight-sensing board kit or perhaps both? Is that a long term plan or a medium term plan? Basically what I'm trying to say here is "take my money!"justin_le wrote:Up until this point I had always been chucking the truck hangar in a lathe in order to machine a round section concentric with the axle for the motor to slide on, which isn't something that most people have the ability to do. But the Rojas trucks have a totally round steel hanger that means we can fit an inline motor on the truck with no modification.
Same here! Except that I do live close enough to work that I could ride a board there, and say, enjoy a cigar on my way. Not to mention it would be perhaps the very fastest form of on-campus transportation. Our city is very hilly (I ride an 18%er every day) so regular boards aren't practical. You'd be walking 60% of the time, uphill or downhill.ohzee wrote:Yea this thread makes me want to start practicing on a skate board again.
As a kid I used a skateboard to get around and worked quite well. Just been a long time.
Google wheatstone bridge.Nordle wrote:Any chance to buy a set of strain gauge + pcb? how does it work, pwm?
Yee.. but I wan't finished product not building my own.Arlo1 wrote:Google wheatstone bridge.