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Arduino DMX receiver design - improvements

bytebitten

I am trying to design an Arduino based DMX receiver for use in a show where we have some custom builds.

In this case; we want to control a LED strip over DMX.

The design has 2 options for control: over DMX or WiFi. The toggle switches between DMX, WiFi or none.

The WiFi will be for debugging/testing of when using at home.

 

For what I found as seen in the image, I have some questions / doubts about some elements:

  • Are the resistors correct? Especially the 68, 22 and 120 Ohms.(one 120 ohm at the end)
  • Will this wiring work for the MAX485?
  • Is it needed to disconnect Rx/Tx prior to flashing new programming on the Arduino?
  • Is the ESP-01 done correct? (improved again in v3)
  • Will the dip-switch work this way? (Arduino sets pinmode input_pullup)
  • Is the 470 Ohm resistor advised for controlling the LED strip? (Seems advised for pin protection with power-on current)

 

Old design v.1:

image

Design v.4:

image

Notes:

  • The Arduino is the 5v version
  • The 470 Ohm resistor goes to the LED strip
  • The LED strip has its own power
  • The toggle2P3T slide switch has the states [Rx+Tx > ESP], [Rx > MAX485, Tx > none], [Rx+Tx > none]
  • The build will be done in phases (LEDs>red>green>blue>yellow) to keep it all working

 

If someone has remarks, improvements or questions; keep 'm coming image

I am still not very experienced in this stuff, but you learn best by doing image

 

Message was edited with v2, v3 and v4 in bold.

v1 replaced for search engines.

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  • 0

    Hi Ruben,

     

    Are all the components in the module? Including both connectors? If so,I would not place the 120ohm resistor in that way, I would connect the connectors 1-1, 2-2, 3-3, the 120 resitor conected pin2-resistor-pin3, and it would be posible to disconect it, then I would place the 22ohm resistor, conector pin2-resistor-B, connector pin3-resistor-A.

     

    About the ESP-01, I think it works at 3v3, so for the Rx it should be place a voltage divider, its seems it is not well wired in the schematic.

     

    Also I would use different pins instead a toggle, so different UARTs in the Arduino, one for the 485, and another for the ESP, then with a toggle connected to digital input, you can switch to decide which UART to use (by software).

     

    Hope to be usefull, regards

  • 0 in reply to gihu

    For the DMX; I will check what resistors are excessive. From your answer I get some are.

     

    For the ESP-01; the Rx/Tx from 5v>3.3v needs a divider; that is where the 1K and 2K are for.

    But 3.3v>5v is compatible as they both have the same thresholds (where 2.4+v registers as up/1, if I'm correct).

     

    The UART pins would work, but from what I read these needs to be disconnected if reprogramming the Arduino. I want to do that without taking it all appart.

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  • 0 in reply to gihu

    For the DMX; I will check what resistors are excessive. From your answer I get some are.

     

    For the ESP-01; the Rx/Tx from 5v>3.3v needs a divider; that is where the 1K and 2K are for.

    But 3.3v>5v is compatible as they both have the same thresholds (where 2.4+v registers as up/1, if I'm correct).

     

    The UART pins would work, but from what I read these needs to be disconnected if reprogramming the Arduino. I want to do that without taking it all appart.

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