How do I use the serial commands?

[rhannink]

Hello,

First off all, great product, works like a charm, but I would like to connect it to my domotic system (HA) and Google system.
I recompiled the code with the #define SERIALCOMMS.

I flashed the firmware with a pocket AVR programmer and this all works fine.

When I connect an FDTI232 to the pins MISO and SCK I see the following commands in my terminal when I press the up or down button.

14:51:02.422 -> <+���<+���<+���<+���<+���<+���<+���<+���<=�z�<+���<=�⸮�<+���<=�⸮�<+���<=�⸮�<+���<=�⸮�<+��<=�⸮�<+� �<=�⸮�<-� �<-���<-���<-���<-���<-���<-���<-���<-���<-���<-���<-���<-���<=�⸮�<-���<=�⸮�<-���<=�⸮�<-���<=�{�<-���<=�f�<-��<=�Z�<-� �<=�Q�<-���<=�N�<+���<+���<+���<+���<=�⸮�<+���<=�⸮�<+���<=�⸮�<+���<=�⸮�<+���<=�⸮�<+��<=�⸮�<+� �<=�⸮�<-� �<-���<-���<-���<-���<=�⸮�<-���<=�⸮�<-���<=�o�<-���<=�W�<-���<=�B�<-��<=�6�<-� �<=�-�<-���<=�*�<+���<+���<+���<+���<+���<+���<+���<+���<+���<+���<=�⸮�<+���<=���<+���<=�)�<+���<=�>�<+���<=�P�<+��<=�\�<+� �<=�e�<-� �<-���<-���<-���<-���<-���<=�⸮�<-���<=�⸮�<-���<=�⸮�<-���<=�⸮�<-���<=�⸮�<-��<=�⸮�<-� �<=�⸮�<-���<=�{�<+� �<+��<+���<+���<=�⸮�<+���<=�⸮�<+���<=�⸮�<+���<=�

So that looks ok, but how can I sent a command via a serial terminal program? I tried to sent <- and <+ with or without returns, but nothing happens. What am I missing. Do i need to sent more bytes ? Can I use a serial terminal command line at all to sent commands?

Eventually I would like to use an ESP(8266 or 32) to control the megadesk. Maybe someone has some example code on what command/bytes exactly to sent over the serial line?

Thanks in advance
Remco

[tagno25]

Here is where I described the command structure
#12 (comment)

The commands are mostly binary, with ASCII command indicators.

For initial testing I was using Termite with the "Hex View" plugin.

[rhannink]

Thanks,

Ik will look into that...

[philwmcdonald]

With #70 there's the option of enabling pure ascii commands/responses. No need to read/write raw bytes over serial to control.
format is very similar to before:

<W3000,3.     # writes  location 3 with height 3000.
<T3000,255.   # plays a 3000Hz tone for 1sec
<C0.0.        # reports current height
<+300..       # nudge desk up by 300
<L,5.         # recall position from slot 2
<l,5.         # recall position from down-button slot 2
<R.0/         # read eeprom slot 0

After the marker byte '<', there's the Command byte, then two fields of ascii integer digits.
Terminate each field with any non-digit character eg !,./ or a line-break.
missing digits are interpreted as a 0 so <L.. is valid and passes two 0s to the L command.
First field (position) can be any number up to a maximum of 65535, the second field (slot) has a maximum of 255.

  data start (first byte)
    char   meaning
  -----------------
    <      start Rx Marker

  command (second byte)
    cmd    meaning
  -----------------
    +      increase
    -      decrease
    =      absolute
    C      Ask for current location
    S      Save location to (UpButton) EEPROM
    s      Save location to Downbutton EEPROM
    L      Load (Upbutton) location from EEPROM and move
    l      load Downbutton location from EEPROM and move
    W      Write arbitrary data to EEPROM
    R      Read arbitrary data from EEPROM
    T      play tone

  position (third/fourth bytes or 1st digit field. max 65535)
    cmd    meaning
  -----------------
    +-     relative to current position
    =SsW   absolute position
    T      tone frequency
    CRLl   (ignore)

  push_addr (fifth byte or 2nd digit field. max 255)
    cmd    meaning
  -----------------
    SLlWwR EEPROM pushCount/slot
    T      tone duration/4 ms. (250 == 1s)
    +-=C   (ignore)

[rhannink]

Hello,

Finally found time to implement the serial commands. I flashed the latest firmware with the serial commands enabled and connected a esp8266 to the serial port. I loaded the following ESPHOME code onto the ESP and now I can control my Ikea desk from Home Assistant and through Google Home (Ok Google activate standing/sitting/middle)

  name: desk
  platform: ESP8266
  board: d1_mini

logger:

api:
  password: ""

ota:
  password: ""

wifi:
  ssid: "xxxxxxxxxxx"
  password: "xxxxxxxxx"

  ap:
    ssid: "Desk Fallback Hotspot"
    password: "xxxxxxxxxx"

captive_portal:

uart:
  baud_rate: 115200
  tx_pin: D0

switch:
  - platform: uart
    name: "Desk up"
    data: '<L0,4.'
  - platform: uart
    name: "Desk down"
    data: '<L0,3.'
  - platform: uart
    name: "Desk middle"
    data: '<L0,5.'

This code automatically gives me 3 switches within HA.
Works great, also the possibility to recalibrate and set the min and max heigth is a welcome addition.

Gr. Remco

[gcormier]

Wow, that's awesome that it was so easy with esphome! Nice work!

[rhannink]

Only to bad, the power regulators of the megadesk can only deliver 5V/500mA. Now I need an additional powersupply to feed the ESP. Maybe in a new version you can upgrade the regulators to 1A or 1.5A types (they have same package I think). And maybe add an extra sideways connector with RX,TX,5V and GND. The current header cannot have a paring connector due to the height of the housing.

Keep up your great work...

Remco

[gcormier]

The issue is not the part itself, but the thermal limitations of a linear regulator in a small space.

https://www.gadgetronicx.com/calculators/linear-regulator-power-dissipation-calculator/

It is best to tap the 24V(30V) independently to power the secondary MCU with an independent regulator, DC BUCK or linear.

[rhannink]

Maybe it helps if you cascade the 7812 and the 7805 to lower the voltagedrop, but the 7812 then needs to deliver more power, still a lot of heat dissipation.
I will use a buck converter to bring down the 24V to 5V.

Thanks.

[gcormier]

At the end of the day there is still around 7-13W of power to dissipate. A buck would be best for sure :)

[benfysh]

@rhannink have you documented this in more detail anywhere? Thanks

[rhannink]

Hello @benfysh,

I did not find the time to document this project on GitHub. What I did was:

• Buy Megadesk controller on Tindie. https://www.tindie.com/products/gcormier/megadesk/
• Flash the controller with the latest firmware with serial commands enabled. You need the Sparkfun AVR programmer for this
• Flash a Wemos D1 mini (or any other ESP) with the esphome software.
• Connect de D0 pin from the ESP8266 (TX1) to the RX pin of the megadesk (PIN 4 MOSI)
• Power the ESP8266 from the Ikea Desk by using a 24-5V Buck converter
• Configure the ESP8266 in Home Assistant with the following settings:

 name: desk
  platform: ESP8266
  board: d1_mini

logger:

api:
  password: ""

ota:
  password: ""

wifi:
  ssid: "xxxxxxxxxxx"
  password: "xxxxxxxxx"

  ap:
    ssid: "Desk Fallback Hotspot"
    password: "xxxxxxxxxx"

captive_portal:

uart:
  baud_rate: 115200
  tx_pin: D0

switch:
  - platform: uart
    name: "Desk up"
    data: '<L0,4.'
  - platform: uart
    name: "Desk down"
    data: '<L0,3.'
  - platform: uart
    name: "Desk middle"
    data: '<L0,5.'

Now you have 3 switches available in HA for 3 different presets (I have 3 presets programmed in the megadesk controller 1-low, 2-high and 3-in between).

[tobru]

I wrote a blog post about it, maybe it helps: https://tobru.ch/ikea-bekant-table-control-over-mqtt-with-megadesk-and-esp32/

[benfysh]

@rhannink & @tobru thanks both looks like I have a few more things to buy :) Megadesk is already working well for me I just like the idea of automating it and running automation when it is set to different heights.

[rhannink]

@benfysh , indeed it is very cool, once it is hooked up to HA you can also control it with Google Home. "Ok Google I want to standup", "Ok Google, I want to sit down".

[gcormier]

Gonna add a todo to bring out some info in the docs so people don't have to dig in issues for the commands.

[gcormier]

Added serial/esphome documentation to bottom of readme.