Weight Sensing Longboard with Inline Wheel Motors

Nordle said:
Arlo1 said:
Google wheatstone bridge.
Yee.. but I wan't finished product not building my own.

You asked how it works......

In order to get a finished product you need to buy a working long board....
 
Ok I thought I could get the sensors + pcb and wanted to know what signal it gives to my controller?^^
Sorry for the misunderstanding
 
Nordle said:
Ok I thought I could get the sensors + pcb and wanted to know what signal it gives to my controller?^^
Sorry for the misunderstanding
Lets see if Justin reply's to that. I can't remember if he offers that. I know it takes a special epoxy and might need some machining on the trucks.
 
Take 3... (apologies for the mismatched front and rear wheels)

Trucks1.jpg
Trucks2.jpg
Trucks Side.jpg
View attachment 5
Deck Routed.jpg
Parts Placement.jpg
Finished, Bottom View.jpg
Finished, Side View.jpg
Finished, Side Profile.jpg


http://makerfaire.com/bay-area/
 
Justin,

Looking at the bottom of the board photos I can identify the two strain4 op-amp boards on the front, and the two controllers at the rear, but can only assume that the display/circuit board at the front of the board is a CA minus the housing?

[edit: I went back in this thread and Justin already clearly answered this question -- the answer is "yes" ... ]


Which controllers are you using to drive the motors? [edit: same as above -- answer is "ASI BAC500" controllers]

Assuming your use of a CA, is your throttle control based entirely on torque readings from the strain gages, or are you adding a PAS/RPM component to the CA settings from some unseen sensor(s)?

[edit: this question seems to be still open -- I didn't see any references to PAS inputs being used, and on thinking some more about it, I'm not sure what role this might play in the operation of the board.]]
 
Clean board Justin! Nice work!
 
Vanarian said:
Oh, where are the weight sensors hidden?
https://endless-sphere.com/forums/download/file.php?id=193932
 
Vanarian said:
Oh, where are the weight sensors hidden? Looks good, you should make cover for the cables glued on the trucks!

Ha yes, actually I deliberately left the cable run and the strain gauges visible and not covered up for the sake of being able to show and explain to people how it's done while at Maker Faire. But on the next run I'm going to machine a thin channel for the signal wire routing right in the aluminum and then backfill the channel so that the internal wiring is both completely hidden and protected. I have to say that working with these machined china hangars that come with the chinese hub wheels is a lot easier than the cast or forged trucks of previous builds, and the strain gauges seem a lot better behaved too with almost zero drift.

Knowing that we can just CNC machine a truck from a single piece of plate aluminum we'll try to design one that not only has the strain gauges and wires embedded but also the strain amplifier circuitry so that you could just provide 5V to the truck and get a ~1-4V signal back based on the weight. That would make it simpler for people to interface directly with arduinos or VESC's or whatever.

rowbiker said:
Looking at the bottom of the board photos I can identify the two strain4 op-amp boards on the front, and the two controllers at the rear, but can only assume that the display/circuit board at the front of the board is a CA minus the housing?

Yes indeed. Here's a closer shot of that.
Skateboard CA and Strain Amps.jpg
With Truck Installed.jpg
The more cushioned foam grip tape on this Landyachtz deck that we used made it really easy to slip a thin acrylic window over the cutout for the CA so that the screen is protected.
Embedded CA dop view.jpg
The firmware is a custom derivative of the normal CA firmware which uses the Aux and Torque analog input lines as front/rear weight signals.
 
Really great project you have there.. nice to see how it has evolved and all the hurdles you have faced to improve it and to make it as it is for you now..

Is there any follow up on this one? Seems like nobody has really asked any questions..

Dont you consider selling these ''sensor fitted'' trucks to anyone? If people are willing to pay sometimes close to 100usd for a controller, then I think you might get more than a few customers, if the cost can be reasonable. as the trucks would be also included..
 
Okami said:
Really great project you have there.. nice to see how it has evolved and all the hurdles you have faced to improve it and to make it as it is for you now..

Is there any follow up on this one? Seems like nobody has really asked any questions..

Ha no follow up on the forum but it's been performing rock solid since we finished it last spring and everyone who gives it a test ride when visiting our shop is blown away at how well it works.

Dont you consider selling these ''sensor fitted'' trucks to anyone? If people are willing to pay sometimes close to 100usd for a controller, then I think you might get more than a few customers, if the cost can be reasonable. as the trucks would be also included..

That is totally the plan. Actually on our next build I'm going to put the weight sensing elsewhere so that it can work with a majority existing motor/hangar setups, as that will be more universal and also easier for doing the electrical cable routing, and that is probably the approach we would use for the commercial venture. The truck will also have the strain gauge signal conditioning circuitry built in it so that you could just power it from 5V and then get a signal in the 1-4V range proportional to the weight. Then it should be easy for people to interface with their motor controllers with a simple arduino circuit or similar if they don't want to have a Cycle Analyst on their deck.
 
Grin posted new info about their weight sensing electric longboard:

"This one is very close to hitting all the marks for an electric skateboard conversion kit using our hands free lean control, including suspension trucks and a ruggedized miniature deck mounted CA." It's using LiGo batteries and "Potted dual FOC motor controllers".

More info and photos:

http://www.ebikes.ca/news/main-st-expo-maker-faire/
 
It's big news. Best skateboard in the world with that equipment. The man hours that have gone into developing that my mind boggles. This is the next era for ridables right here. Throttle, controller, batteries and motors are all executed so well. What a package.
 
travellin said:
Grin posted new info about their weight sensing electric longboard:
http://www.ebikes.ca/news/main-st-expo-maker-faire/

Indeed! Thanks for picking up on this. We had a pretty great showing of the boards at the Vancouver maker faire last weekend and both the recent builds survived 2 days of non stop use by kids, teenagers, and the odd adult. If anyone's ever exhibited a demo at a maker faire, you know this is no small testing ground for things to go wrong.

Rather than continuing on with this development thread, I decided to start a new one more specifically focused on the parts of a grin electric board kit here:
https://endless-sphere.com/forums/viewtopic.php?f=35&t=88901

Hummina Shadeeba said:
please post up the trucks when they're available.

Just follow this new thread above Hummina and I'll be talking about availability in the coming weeks.
 
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