Metr app records GPS data together with VESC data

EFOIL.builders Electronics (ESC, remote, batteries)
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Get the app here: https://metr.at/
Have a look here, my first recording: Jun 2, 2019 - metr.at | wz32k
Have fun!

P.S.: Just to be clear: This data was recorded with a large windsurfboard without any foil.

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This is a good point. You can choose in the app if you prefer GPS data over the RPM based speed information. I tried this, gave motor poles 14 and 178mm diameter of the wheel and got speeds above 100km/h calculated :roll_eyes: .

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14 poles pairs no ? So may be with 7 and including propeller slip on the pitch : 7 and 130mm?

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Cool DATA !
Which VESC do you use ?

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Here are some of mine:

I use the Vesc six, it works great on top of the mast with proper cooling and a very torquy motor

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Got any pics of how you mounted it to the mast?

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Can you access to raw data in which you can copy paste rpm AND GPS data into your favourite spreadsheet ?
Or is it a SW switch that is made at processor level which is not powerful enough to compute both rpm AND GPS data at the same time but only ā€¦ rpm OR GPS data ?

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@Jezza sure hereā€˜s an old one:

image
56433B7F-EE92-4975-91CA-0939429FB0B2.jpeg3024Ɨ4032 2.39 MB

Will update my build thread soon.

Unfortunately up to now I didnā€˜t find a way, but in the app you can get more precise time steps and values.

3 Likes
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190412%20Peter%2035kph%2056pc
Your first log (12th April 2019) is impressive. 35kph at only 56% duty cycle before decelarating to 11kph in 10 secondsā€¦
Q1: What is your highest speed ever reached with your setup ?
Q2: What is your foil and its high AR front wing ? Levitaz or similar ?
Q3: Passed 35 kph, you enter another sport. Are you using straps or foothooks ?

As I am not familiar with formulaes, can sbdy help me ?
Q4: Can I say that the instantaneous power drawn from the battery is then U x I = 46.3V x 22.4A = 1037 W that would be more or less what @ELEVATE.rocks got in october 2018 with his optimised RL front wing at 300.000 Reynolds ?
Q5: can you extract the torque from your raw data. How de we calculate the torque from that data ?

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Iā€™m guessing you not using the tracks in the board? Or have cut through them and glassed it accordingly. I must look at the temperature data from your setup. I think mast cooling is probably the best and most sensible by far.

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[Edit] Looking at all those cooling fins that have appeared during the past months, I am not so sure that the contact surface between mast and plate is sufficient to be the best asset of this solution over a certain drawn power therefore speed. Time will tellā€¦

flightbox-1

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Hi @SoEFoil, topspeed up to now is little over 40km/h, more is possible, but as you write, beyond that is an adrenaline ride :wink:
The wing is an old simple fanatic SUP type, so not the fastest.
From the consumption point of view, it might be more than what you wrote, as you have to accelerate to that speed first. Peak right before is at 3.5-3.7kW at 85-93% duty cycle. So still buffer. With a faster wing you can go easily beyond.

1 Like
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Hi Sir,

Iā€™m an electronics engineering student and i just started working on efoil project. So i was wondering if you can provide me with some informations about the surfboard tracking.
and thank you.

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Hi Peter,
nice to see that you are riding on Chiemsee - Iā€™ve had my first test yesterday near Seebruck :surfing_man:
You are living there? Would be great to fly together next time :sunglasses:
Mike

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Hi @Hazem, Metr is a small blutetooth dongle that you can directly plug and play on the Vesc. Itā€™s a great and easy to use tool, with which you can monitor many parameters.

There is now another dongle by Trampa available, but I didnā€™t use it up to now.

Hi @SUP-MIKE, yea, it would be great to have a ride together!:slight_smile: Letā€™s do it!

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i understand metr is a device that we plug on the Vesc. But i donā€™t understand yet how we can collect data and display it on this app. Can you please provide me with some informations (where can i find this device? how can i display data? or is there a tutorial that explains how we do ?)

And Thank you again :slight_smile: .

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I had no chance with the trampa module and my pc with Windows ā€¦ Just order the metr at module at : metr

iOS 11 ā€¦

Trampa only Linux and Android 8.0+ for Smartphone , for pc on Windows i use the usb so far (?)

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FAQ and Setup guide are available by clicking on the top left menu symbol (3 horizontal lines).
The information is minimalist.
Better info probably available at support@metr.at

Menu

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thank you for these informations :blush:

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Would be great if one of the moderators (@pacificmeister @Hiorth @tylerclark) can allow iframes for the Metr App records like it is described here: