ELRSk8 - ELRS remote

[vap]

Ok, he’re we go, I’ll probably edit this post multiple times. But I need to start somewhere, and I think version 1.0 is ready.

GITHUB - GitHub - vapgames/ELRSk8-ELRS-Skateboard-Remote: ELRSk8 is an open source electric skateboard remote utilizing the power of ExpressLRS
//THINGIVERSE POST INCOMING
//MORE DIAGRAMS INCOMING
//MAYBE BUILD VIDEO

I wanted a remote with a number of specific features:

• High reliability, low latency connection. ELRS.
• Durable throttle control with bearings, high reliability sensor and tension adjustment.
• Ergonomic grip for use with wrist guards and gloves.
• Telemetry.
• 3d printed with easily sourced components.

I’ve been gradually working on this project for over a year, at this point I’ve implemented all key features, and I’ve been riding using the prototype for the last 6 months and it works great.

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Remote config:

• ExpressLRS (ELRS) - Currently it is the most reliable opensource link protocol with great interference and failsafe handling. ELRS receivers can be configured as transmitters, and there’s a huge selection of different models. You can use any esp8285 based receiver for TX, I recommend “Happymodel ep1 TCXO” as TX and “Happymodel EPW6 TCXO” as RX.
  
  aliexpress ep1
  aliexpress epw6

• controller: RA4M1 it’s compact and setup is straightforward. Alternatively you can use STM32F103C8T6 Blue pill (but you need to flash bootloader and remove pins to make it fit). Xiao RA4M1 OR Waveshare RA4M1
  
  aliexpress RA4M1 and Waveshare

• Sensor: SS49E or A1324 linear hall sensor.
  
  aliexpress link

• Cylindrical neodimium magnets 5x3

• Bearings: MR128 ZZ (or MR128 RS) 8 * 12 * 3.5mm
  
  aliexpress link

• Spring from Bic lighter.

• Battery: 802540 or 902540 900mah li-ion spicy pillow (lasts >6 hours, haven’t tested beyond that)
  

• Usb C port: generic pcb soldered 4 pin port.
  
  aliexpress link

• 6x6x7 button for telemetry menu
  

• Power switch: KCD1-110
  
  aliexpress link

• OLED 0.49" i2c 64x32
  
  aliexpress link

• Power supply:

  • 5v UPS module ND1A05MA - combines 0.5A charging and discharging, but seems like it’s not very widely available
    
    aliexpress link

  • alternatively you can use 2 separate modules for charging and discharging. Look for 500ma small capacity charging module + 5v boost module
    
    aliexpress charger
    aliexpress boost 1 or boost 2
    MAKE SURE YOU SET BOOST TO 5V, stock is 12v, I’ve killed 1 controller like that

• Shell printed with PETG (or any other low friction material). Grips printed with TPU95a.

• Hardware

  • set of m2 screws 6-12mm aliexpress link
  • m5x4 or m5x4 set screw (same as in HTD5m pulley)
    

• Optional WS2812 LEDs

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Receiver

• Any ELRS receiver will do. But if you want to have telemetry at this point you’ll need a PWM receiver. I use Happymodel EPW6, it can do UART and PWM at the same time.

• For telemetry - same RA4M1 / STM32F103C8T6 to talk to VESC (or any other arduino-compatible controller that can do 2 UARTS)
  

  

[vap]

Board config is done on receiver side, so you can seamlessly use same remote with multiple boards with different cell/wheel/gearing configurations.

Here’s a little info on how to deal with ELRS:

How to enter ELRS WIFI mode

• For me ELRS WIFI doesn’t work on my laptop, but it works on my phone.

• By default ELRS receiver/transmitter will go into WIFI mode 60 seconds after power up, if there’s no connection.

• For fresh receiver you can power it with GND and +5v and wait 60 seconds.

• If connection was established between remote and the board receiver, it will not go into WIFI mode until power cycle. So to connect WIFI to your board - keep remote turned off, power the board on, wait 60 seconds.

• For soldered remote, the TX module will not go into WIFI mode while it’s receiving packets from arduino controller. To go into WIFI mode you need to flash empty sketch (like a blinker sketch) onto the remote, then wait 60 seconds.

• Choose WIFI named ExpressLRS RX (or TX). Press “Use network as is”:
  

  

• After this you can go into a browser and type address 10.0.0.1
  Here you can set your Bind Phrase, tweak pin settings, and upload the firmware (that you download from web flasher)
  

  
  

How to flash Ep1 as TX

Go to ExpressLRS Web Flasher
Choose Receiver:

Choose latest ELRS and these receiver settings:

Set your bind phrase, go to Advanced Settings and check “Flash RX as TX”

Either download firmware and flash using WIFI (to be added).

Or flash using FTDI adapter and UART, while boot pins on the receiver are shorted (to be added).

How to configure EPW6 for PPM and UART telemetry

CH1 is throttle PWM, I’ve increased mine to 100HZ, test this for your particular VESC. Make sure to setup failsafe pos to 1500.

CH2 and CH3 should be Serial TX and RX.

How to flash with FTDI adapter

The “I wasn’t asking” method that I prefer over WIFI flashing.
//schematic

[dimos15]

Awesome! can’t wait to try it

[vap]

Updated receiver chematic, wrong UART connection.