Hey everyone!
Together with @hexakopter we present you the all new Metr Pro bluetooth module! It is based on the latest tech from Nordic nRF52 and packs a punch!
Hardware Features
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Metal Shield for interference protection. This is very important because a lot of EMI is coming from our high current fast switching setups in some cases disturbing the correct operation of the module. The main unit is shielded to mitigate that.
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Optional external 2.4GHz antenna. Recommended if you have carbon fiber enclosure or you experience a lot of issues with bluetooth module disconnecting. It makes a noticeable difference. In our tests external antenna doubled the range of operation. But even the default configuration with internal PCB antenna still has much better connection than HM-10.
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Three bright colored LEDs for easy diagnostics.
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Blue LED (bottom) is for bluetooth. When it is blinking slowly, the module is in Discovery mode. It is advertising and you should be able to find it within your mobile app. |
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Blue LED rapidly blinking means the data is exchanged via bluetooth. Each incoming and outgoing bluetooth packet results in a little blink. |
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Green LED (center) is for UART. When it is blinking the module is negotiating BAUD rate and RX / TX pin positions. Usually after half a second it becomes solid green which means the negotiation is successful. |
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Red LED (top) is for errors. When it’s ON, some error has happened. It might be wrong security PIN code, or UART communication problem. Metr Pro will try to report this error back to the Metr app. |
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Additional nRF52 pinouts on the back of the module. Currently these pins are not used but we might have some ideas like adding a Micro SD card or another UART to communicate with some other stuff
Software Features
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BLE security with Elliptic Curve Cryptography and Man-in-the-Middle protection. All the modules that we use today have bad security or no security at all. It is only a matter of time before someone starts messing around with it. Think about it this way: your board can be hacked, your settings can be messed up, this can result in serious injury. The chance is very low, but why risk?
Metr Pro will never bypass communication from an unpaired phone to the VESC. Each Metr Pro module has a random 6 digit PIN code label on the back side which is used for pairing. Once paired, all the communication is encrypted and secure. -
Works with all the apps. We made sure Metr Pro supports every VESC app. There are more and more apps and they are getting better and better. Thanks to all the amazing software developers out there!
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Latest updates from Benjamin made possible what we call VESC Tool Direct. Forget about TCP Bridge. Connect directly from the desktop version of VESC Tool. Supported on Windows, Mac and Linux.
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Works with all the hardware. No matter what VESC variant you have, no matter what firmware you have installed*, no matter what BAUD rate you have, Metr Pro works with everything. It has automatic BAUD rate detection and automatic RX / TX pins detection. There is only one cable and only one way to connect it. After being connected it detects RX and TX pins as well as BAUD rates programmatically until successful connection is made. And it has no issues with Android Oreo.
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Updatable over the air. The module itself is running a special firmware that implements the whole BLE stack, UART, VESC protocol + custom Metr protocol. New features can be (and will be) constantly added and you can update the module effortlessly with the Metr app over the air.
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Parallel VESC firmware update with automatic settings backup and restore. With just one click the new firmware can be sent simultaneously to both of your VESCs connected via CAN and motor + app configuration will be restored after the update. Everything in just one minute. Ben and Nico have been hitting hard with the new updates and we think that is awesome. With Metr Pro you can keep up without too much hassle.
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Startup Mode. From the Modes tab you can assign one of your modes to be a startup mode and it will automatically apply when you power on your VESC, even if your phone is not around. I like to use it as a warm up. I set up a mode with low-amp, low-speed as startup and ride it for 5-10 first minutes before changing to a faster one. This helps to avoid the stressful situations I sometimes had when accidentally pushing trigger too much in the morning on the way to work.
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True Dual Realtime Data. Metr Pro constantly communicates with both VESCs connected via CAN, repacks the data and sends it to the Metr app. Just in case you want to see both motor temperatures and both motor currents independently and understand if one motor starts to perform worse and needs some service. The delivery speed and density of Realtime Data is also improved. With these modules you will have faster updates and much more detail.
We can’t wait for you to use Metr Pro in your builds! This module is no longer just a serial bridge between VESC and mobile, it is a full-fledged VESC-addon with smart features. Each Metr Pro is crafted in Germany by @hexakopter and individually tested before shipping. It is available starting today. Get yours now!
Pricing:
Metr Pro €40 Metr Pro with external antenna €52 For EU customers there is additional 25% VAT Worldwide shipping: €12
Now hit us with your questions!
I should trade up from my hm-10…
Also VESC-Tool doesn’t work well with BLE devices iirc in some Operating Systems 
I refuse to use CAN.