This article describes a project with no implied warrany of any kind. Try it and use it at your own risk. Always wear a helmet for your safety and knee/elbow pads.
keywords: electric skateboard, Ridekick, fun, DIY, arduino nano, bluesmirf, bluetooth, roboremo app.
This projects has 2 parts: the skateboard adapter and the bluetooth control system upgrade.
What is it ?
-Your favorite skateboard or longboard pushed by an electric bike pusher trailer.
Does it have brakes?
- No, use your feet instead as on a regular skateboard.
Positions?
- Sitting & standing.
How do you make it work? DIY skateboard adapter
- DIY: bend a 1/4 in. thick piece of steel in a vise with a hammer to get it "L" shaped, dill holes in it for attachment screws and hitch bolt. No wizardry involved.
Sitting on it :
How far does it go?
- Depends on your battery, i have a Lead-acid 12AH that goes 12km or 8 miles ish and a LiFePO4 50AH that goes 100km or 60 miles ish with a bike, perhaps less here with those smaller wheels...
How fast does it go?
-i d recommend using it on the "P0" setting to prevent going too fast and accelerating too much - remember there are no brakes!
What about the electronic part?
- 2 options: use the throttle that comes with the Ridekick or make your own bluetooth control system as follows:
What parts do i need for the DIY bluetooth control system?
-the e-trailer - you ll have it already perhaps... https://ridekick.com/
-arduino Nano (see ebay).
-Bluesmirf bluetooth silver bluetooth adapter (https://www.sparkfun.com/products/12577) or you can try one super cheap bluetooth adapter from china...good luck with that as they are super hard to program and use, if they ever work.
-a dc-to-dc high efficiency converter to get ~5V DC from the 24 V battery of the ridekick (do not use the ridekick usb port as it only delivers 25mA before switching to error mode). - a dc to dc step down converter like a 2A LM2596 buck power converter 4-40V - at 150kHz (genuine).
-a few resistors and capacitors, a LED. see schematics.
-terminals and a prototype soldering board.
- XT60 male plug to solder
- Cu wires
The simple soldered connections
Schematics of the circuit board:
Video of the prototype spinning the wheel:
Arduino Nano source code to compile in IDE and upload on chip:
(select OLD Bootloader in the "tools/processor" menu, if your arduino is pre-2018 or replica from China)
/*****************************************************************************
//created by Maxime Cuypers on 29-march-2021 for ridekick control by bluetooth with roboremo on android phone
//bluetooth module Bluesmirf silver (10m range)
//
* AUTHOR : Maxime Cuypers
* COMPANY : private
* REVISION : 0.1
* DATE : 24/04/2021
********************************************************************************/
#include <SoftwareSerial.h>
/*******************************************************************************
* IO DEFINITION *
*******************************************************************************/
//setup bluetooth bluesmirf port
int bluetoothTx = 2; // TX-O pin of BT module to Arduino pin2
int bluetoothRx = 3; // RX-I pin of B module to Arduino pin3
SoftwareSerial bluetooth(bluetoothTx, bluetoothRx);
//const = variable "read-only".
// PWM is connected to pin 7.
const int pinPwm = 5;
int val=0;
int val2=51; // ridekick must start with throttle at 1-1.5V as zero speed.
int count=0;
unsigned long now; //unsigned to prevent problems with large numbers
/*******************************************************************************
* PRIVATE GLOBAL VARIABLES *
*******************************************************************************/
char cmd[1000];
int cmdIndex;
void exeCmd() { //runs only when a command is received
if( cmd[0]=='v' &&
cmd[1]=='i' &&
cmd[2]=='t' &&
cmd[3]=='e' &&
cmd[4]=='s' &&
cmd[5]=='s' &&
cmd[6]=='e' &&
cmd[7]==' ') {
String cmdStr;
String valueStr;
cmdStr = String(cmd);
valueStr = cmdStr.substring(8);
val = valueStr.toInt(); //special thanks to LP to get this to work
//for ridekick - voltage value |1-4|Volt range only. otherwise error E2. 1-1.5V = stop, 4V = full speed
//startup only 1-1.5V allowed, or E3
//E7 if usb throttle line (5V) draws more than 25mA.
// since val is stored into integer, decimal not stored, add .0 to allow decimal
val2= 51.00 + ( val * 0.66 ); // val2= 51.00 + ( val * 0.66 ) input 0-255 from roboremo, output 51-204 (1-4 Volt) here. Attention 1-3.18v if ridekick off. - full compatibility with train DC control board then. 0.6 +0.06 for adjustmnet with the LED take bit of power
analogWrite(pinPwm, val2);
}
if(cmd[0]=='s') { // stop
analogWrite(pinPwm, 51); // ridekick speed zero at 1 volt
delay(1000); //wait 1s after emergency stop before any other restart
}
if(cmd[0]=='c') { // FAILSAFE heartbeat signal "c" every 650ms from roboremo. see loop below
now= millis();
}
}
/*******************************************************************************
* FUNCTIONS *
*******************************************************************************/
void setup() { // at power on
delay(500); // wait for bluetooth module to start
// Initialize the PWM and DIR pins as digital outputs.(upon reset)
pinMode(pinPwm, OUTPUT);
// pinMode(pinDir, OUTPUT);
// change Bluetooth module baud rate to 9600:
bluetooth.begin(115200); // Bluetooth default baud is 115200
bluetooth.print("$");
bluetooth.print("$");
bluetooth.print("$"); // enter cmd mode
delay(250);
bluetooth.println("U,9600,N"); // change baud to 9600
bluetooth.begin(9600);
cmdIndex = 0;
now=millis(); //initialize the time reference for FAILSAFE
}
void loop() {
if(bluetooth.available()) {
char c = (char)bluetooth.read();
cmd[cmdIndex] = c;
if(cmdIndex<99) cmdIndex++;
if(c=='\n') { // each command ends with '\n'
exeCmd();
cmdIndex = 0;
}
}
//constant detection of presence of signal from roboremo heart beat
if(millis()-now > 2000) {
analogWrite(pinPwm, 0); // ridekick speed FAILSAFE to prevent a runaway!
}
}
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