Published April 5, 2021 © LGPL

Control sit/stand Desk height with a touch screen

Control IKEA Bekant Desk sit/stand height with M5Stack Core2 using two Relay units and a ToF (time-of-flight sensor VL53L0x) unit.

IntermediateWork in progress4 hours5,048

Control sit/stand Desk height with a touch screen

Things used in this project

Hardware components

M5Stack Core2 ESP32 IoT Development Kit

M5Stack Mini 3A Relay Unit

M5Stack Time-of-Flight (ToF) VL53L0X Laser Ranging Unit (MCP4725/)

IKEA BEKANT Desk sit/stand

https://www.ikea.com/ch/en/cat/bekant-desk-underframes-18965/ 902.552.52 (Underframe sit/stand f table tp, el, white120x80 cm) https://www.ikea.com/ch/en/assembly_instructions/bekant-underframe-sit-stand-f-table-tp-el-white__AA-1006070-9_pub.pdf 302.552.50 (Underframe sit/stand f table tp, el120x80 cm) https://www.ikea.com/ch/en/assembly_instructions/bekant-underframe-sit-stand-f-table-tp-el__AA-1006070-9_pub.pdf

IKEA BEKANT Table top

3M Double Sided Foam Adhesive Pads

To attach Time-of-Flight Distance Ranging Sensor under the desk

Jumper wires (generic)

Make <=> Make (to attach to relays), Male <=> Female (to extend)

Test Probe Connector, Hook

Test Clamp Wire Hook Test Clip (usually for Logic Analyzer) but used to hook to original two button backplane circuit

M5Stack M5GO/FIRE Battery Bottom

N.B. You need the Bottom2 M5GO Battery Bottom2 for Core2 to add port B and C for Relay https://docs.m5stack.com/#/en/base/m5go_bottom2

Software apps and online services

M5Stack UIFlow

Hand tools and fabrication machines

Multitool, Screwdriver

Used to break into the ABS enclosure of the original IKEA control (138684) also used for the 3.96 socket part of Relay M5Unit (Mini 3A Relay Unit) Part of iFixit's Pro Tech Toolkit

Metal Spudger

Used to break into the ABS enclosure of the original IKEA control (138684) Part of iFixit's Pro Tech Toolkit

Halberd Spudger

Used to break into the ABS enclosure of the original IKEA control (138684) Part of iFixit's Pro Tech Toolkit

Hot glue gun (generic)

Story

IKEA BEKANT Desk sit/stand (also available in Black and various colors table top)

The control provided with IKEA BEKANT sit/stand Desk was extremly basic with just two buttons UP and Down.

Basic control with two buttons

IKEA basic control for BEKANT sit/stand Desk

This project describe how I implemented a touch screen interface with 6 memory slots and a precise height mesurement using ST's VL53LOX Time-of-Flight (ToF) sensor, two relays and M5Stack Core2.

Control sit/stand Desk with a Touch screen interface and store up to 6 height values

The - button (left) move down the desk, the + button (right) move up the desk, the M button (center) will save the current height of the desk in any of the 6 memory slots that you will touch next. Pressing any memory button, will move the desk right to the correct height based on realtime Time-of-Flight measurement.

Time-of-Flight ranging sensor (ST's VL53L0X)

ToF M5Unit (Time-of-Flight Distance Ranging Sensor Unit (VL53L0X)

Two Relays (Mini 3A Relay) attached with two LEGO Black Technic pins and jumper wires

ToF ranging sensor (VL53L0X) attached under the desk with 3M double sided foarm adhesive pad

IKEA BEKANT control unit openned to extract button backplane and original circuit

I used the combinaison of iFixit's Halberd Spudger, Metal Spudger and Screwdriver to open it. (this is the second most difficult part)

I embedded the original circuit with three test clamp wire hook test clips in a M5stack case with glue

Ugly! (I agree) but I was not able to solder any cable directly on the flexible button backplane so I used the metal spudger to uncover each of the three lanes and hook them to jumper wires. Simple and no soldering required, only precision.

Hook test clips attached to each lanes (delicate!)

Maybe there is a ribbon flat cable (like for Raspberry Pi camera) with regular jumber cable as clean solution to connect to the 3 Pins (3.3V).

All components in one picture

And yes this is basically an elevator for Cats...

M5Stack's UIFlow with the code in Blocky

Demo time (video)

https://d.tube/v/lordbaco42/QmRSA3gH5yfTULoqZr4ci66VAbjTLQRQ1bw6icr3v8F8h6

Check also my new project using M5Paper

https://m5stack.hackster.io/baco/control-sit-stand-desk-height-with-a-paper-e-ink-display-51837e

IKEA hackers' article and FAQ

https://www.ikeahackers.net/2021/04/ikea-bekant-touch-screen-control.html

Code

M5Stack Python Code

from m5stack import *
from m5stack_ui import *
from uiflow import *
import time
import unit

screen = M5Screen()
screen.clean_screen()
screen.set_screen_bg_color(0x000000)
relay0 = unit.get(unit.RELAY, unit.PORTB)
relay1 = unit.get(unit.RELAY, unit.PORTC)
tof0 = unit.get(unit.TOF, unit.PORTA)


m = None
height = None
m1 = None
target = None
m2 = None
m3 = None
m4 = None
m5 = None
m6 = None
offset = None


height_lbl = M5Label('0', x=151, y=153, color=0x00ff00, font=FONT_MONT_26, parent=None)
bar0 = M5Bar(x=10, y=189, w=300, h=12, min=65, max=115, bg_c=0x707070, color=0x00ff00, parent=None)
label1 = M5Label('-', x=63, y=208, color=0x00ff00, font=FONT_MONT_32, parent=None)
label2 = M5Label('+', x=239, y=208, color=0x00f000, font=FONT_MONT_32, parent=None)
label3 = M5Label('M', x=152, y=210, color=0x00ff00, font=FONT_MONT_20, parent=None)
m1_btn = M5Btn(text='M1', x=35, y=27, w=70, h=30, bg_c=0x000000, text_c=0x00ff00, font=FONT_MONT_24, parent=None)
m2_btn = M5Btn(text='M2', x=125, y=27, w=70, h=30, bg_c=0x000000, text_c=0x00ff00, font=FONT_MONT_24, parent=None)
m3_btn = M5Btn(text='M3', x=214, y=27, w=70, h=30, bg_c=0x000000, text_c=0x00ff00, font=FONT_MONT_24, parent=None)
m4_btn = M5Btn(text='M4', x=35, y=98, w=70, h=30, bg_c=0x000000, text_c=0x00ff00, font=FONT_MONT_24, parent=None)
m5_btn = M5Btn(text='M5', x=125, y=98, w=70, h=30, bg_c=0x000000, text_c=0x00ff00, font=FONT_MONT_24, parent=None)
m6_btn = M5Btn(text='M6', x=214, y=98, w=70, h=30, bg_c=0x000000, text_c=0x00ff00, font=FONT_MONT_24, parent=None)

from numbers import Number


# Describe this function...
def up():
  global m, height, m1, target, m2, m3, m4, m5, m6, offset
  relay0.on()
  relay1.off()

# Describe this function...
def down():
  global m, height, m1, target, m2, m3, m4, m5, m6, offset
  relay0.on()
  relay1.on()

# Describe this function...
def stop():
  global m, height, m1, target, m2, m3, m4, m5, m6, offset
  relay0.off()
  relay1.off()

# Describe this function...
def init():
  global m, height, m1, target, m2, m3, m4, m5, m6, offset
  m = 0
  m1 = 65
  m2 = 75
  m3 = 85
  m4 = 95
  m5 = 105
  m6 = 115
  target = 0
  offset = 2

# Describe this function...
def refresh():
  global m, height, m1, target, m2, m3, m4, m5, m6, offset
  height = int(((tof0.distance) / 10))
  height = (height if isinstance(height, Number) else 0) + offset
  bar0.set_value(height)
  height_lbl.set_text(str(height))
  m1_btn.set_btn_text(str(m1))
  m2_btn.set_btn_text(str(m2))
  m3_btn.set_btn_text(str(m3))
  m4_btn.set_btn_text(str(m4))
  m5_btn.set_btn_text(str(m5))
  m6_btn.set_btn_text(str(m6))


def m1_btn_pressed():
  global m, height, m1, target, m2, m3, m4, m5, m6, offset
  if m != 0:
    m1 = m
    m = 0
  else:
    target = m1
  pass
m1_btn.pressed(m1_btn_pressed)

def m2_btn_pressed():
  global m, height, m1, target, m2, m3, m4, m5, m6, offset
  if m != 0:
    m2 = m
    m = 0
  else:
    target = m2
  pass
m2_btn.pressed(m2_btn_pressed)

def m3_btn_pressed():
  global m, height, m1, target, m2, m3, m4, m5, m6, offset
  if m != 0:
    m3 = m
    m = 0
  else:
    target = m3
  pass
m3_btn.pressed(m3_btn_pressed)

def m4_btn_pressed():
  global m, height, m1, target, m2, m3, m4, m5, m6, offset
  if m != 0:
    m4 = m
    m = 0
  else:
    target = m4
  pass
m4_btn.pressed(m4_btn_pressed)

def m5_btn_pressed():
  global m, height, m1, target, m2, m3, m4, m5, m6, offset
  if m != 0:
    m5 = m
    m = 0
  else:
    target = m5
  pass
m5_btn.pressed(m5_btn_pressed)

def m6_btn_pressed():
  global m, height, m1, target, m2, m3, m4, m5, m6, offset
  if m != 0:
    m6 = m
    m = 0
  else:
    target = m6
  pass
m6_btn.pressed(m6_btn_pressed)

def buttonA_wasPressed():
  global m, height, m1, target, m2, m3, m4, m5, m6, offset
  down()
  pass
btnA.wasPressed(buttonA_wasPressed)

def buttonC_wasPressed():
  global m, height, m1, target, m2, m3, m4, m5, m6, offset
  up()
  pass
btnC.wasPressed(buttonC_wasPressed)

def buttonB_wasPressed():
  global m, height, m1, target, m2, m3, m4, m5, m6, offset
  m = height
  pass
btnB.wasPressed(buttonB_wasPressed)

def buttonA_wasReleased():
  global m, height, m1, target, m2, m3, m4, m5, m6, offset
  stop()
  target = 0
  pass
btnA.wasReleased(buttonA_wasReleased)

def buttonC_wasReleased():
  global m, height, m1, target, m2, m3, m4, m5, m6, offset
  stop()
  target = 0
  pass
btnC.wasReleased(buttonC_wasReleased)

def buttonB_wasReleased():
  global m, height, m1, target, m2, m3, m4, m5, m6, offset
  stop()
  target = 0
  pass
btnB.wasReleased(buttonB_wasReleased)


init()
while True:
  refresh()
  if target == 0:
    pass
  elif height < target:
    up()
  elif height > target:
    down()
  else:
    stop()
    target = 0
  wait_ms(100)
  wait_ms(2)

Credits

Baco

2 projects • 3 followers

Control sit/stand Desk height with a touch screen

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Schematics

M5Stack UiFlow Blocky

M5Stack UiFlow Blocky Code

Code

M5Stack Python Code

Credits

Baco

Comments

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Control sit/stand Desk height with a touch screen

Control sit/stand Desk height with a touch screen

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Schematics

M5Stack UiFlow Blocky

M5Stack UiFlow Blocky Code

Code

M5Stack Python Code

Credits

Baco

Comments

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