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• DSM/DSMX Schematic

  PhillyFlyers • 10/18/2020 at 23:06 • 0 comments

  In case you just wanted to view the schematic (Eagle PCB/SCH files are attached to this project in a zip file)

• MZ-32: Binding with the DSM Module

  PhillyFlyers • 10/18/2020 at 22:46 • 0 comments

  If using the MZ-32, binding is done via the 'I/O Set' menu as shown in the image below.

  First thing you need to make sure you do is have the DATA output set to 'SP'.  Then make sure you also have power applied to the DATA port.

  (See the RED circled areas on the picture below)

  Next step is to click on the CIRCLE with 3 dots, to bring up the SP (DSM) sub menu...

  Next step is to select the CORRECT DSM PROTOCOL, via the 'MODE' menu item on the top left.

  1) MODE 1 ==> DSMX

  2) MODE 2 ==> DSM2

  
  Click on the '---' button next to the BIND button, this will start the BIND sequence, just wait, it could take up to 30 secs before the bind completes.  If nothing happens, try it again.  If it contines to fail, switch the MODE to the other DSM format and try again

  
  Below is what you will see once the BIND is initiaited, eventually it will switch from 'SEND' back to '---' once the sequence completes...

  If the BInd completes, just CANCEL out of the menu and fly your model!   If it all failed, you can tap on the middle power rail (above to (+) in the data port below to cut off the 5V power to the module, and then power it back on, and repeat the BIND sequence.
  

• MZ-32: Attaching the DSM Module

  PhillyFlyers • 10/18/2020 at 22:39 • 0 comments

  If using this module on your MZ-32, you want to make sure you connect the servo wire CORRECTLY to the DATA PORT on the back of the Tx.  There is NO notch on the data pin ports to prevent you from installing it backwards!

  
  Make sure you look at the picture below to see the correct orientation!  The GND (black) wire goes to the RIGHT MOST pin of the 3-pin DATA port!!!!
  

  
  

  
  

• Harvesting an OEM DSM/DSMx RF Module

  PhillyFlyers • 10/18/2020 at 22:32 • 0 comments

  In order to build this module, you will of course need to first locate a genuine Spektrum, Horizon Hobby (or other OEM DSM Transmitter.   It seems as if the following models are currently the cheapest to find for DSM RF Modules.

  1)  DX5e  - Spektrum 5 channel radio (Ebay for approx $45 or so?)
  2)  MLP4DSM  - Horizon Hobby (Blade) 4 channel radio  (Ebay for approx $40 or so?)
  3)  DX6e - Spektrum 6 channel radio - (Ebay for at least $150 + )  -- by far the most expensive route
  

  I'm sure there are others as well that use OEM DSM RF modules, these are just the first 3 I know of..

  It's quite easy to unsolder the RF module from the OEM tx board, with a good large-tip iron for plenty of heat, and a nice spool of copper solder braid.  With these two tools, you can easily heat up and suck up the solder around the pins, and then pop out the RF module.  It's normally just held on the top side with some simple double-sided foam gap filling tape.

  DX5e Module - TOP
  

  DX5e Module (Bottom)  -  Part Number:  X1TX0 REVB
  

  MLP4DSM Module
  

• Assembling the PCB

  PhillyFlyers • 10/18/2020 at 22:25 • 0 comments

  This PCB was designed around SMT (surface mount components), just to save space... I know these can be a little difficult to solder if you don't have a decent iron with a small solder tip, and some type of desktop magnifier or glasses with magnification.

  
  I also added TWO LEDs for 'Power' indication and 'Data' indication.  (The DATA LED illuminates when the signal line goes LOW, since it's inactive state is High.  It will appear to essentially be always on because of the 125k baud uart traffic.. but it is actually pulsating, just quite fast!

  I did NOT populate the JR header on the bottom right in my samples shown, as you don't need to buy/solder on this header unless you plan on using this module in another Tx that has a JR compatible module bay (like a Taranis, etc)... ie you do NOT need this header when using the MZ-32.
  

  
  You can also build the similar board by John Prikkel (http://johnprikkel.blogspot.com/2014/07/jr-dsmx.html) if you are not comfortable with surface mount components.   Flux paste is your friend!!!

  
  ** Note **:   I don't really like the original setup where people are using a simple diode + pull-up resistor in order to interface 5v (or higher) from the Tx UART signal to the RF Module signal in.  It works, but not the best way to do it.  I used a simple 74LVC1G125 line driver/buffer that can put out a nice clean 3.3v signal, and take up to 5.5v on the input even while powered from 3.3v.

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