MiniPiio RS232 v0.10

** UPDATE: You can get these boards at in the DTronixs store

As promised we spent our weekend building the other MiniPiio designs. So without any further ado, here’s the MiniPiio_RS232.

This is for anyone who wants a RS232 port on the Raspberry Pi but doesn’t want to give up one of the two precious USB ports or clutter their desk with a USB hub to use a USB to RS232 adapter.

Unfortunately, there’s a mistake in the dimensions of the PCB. Instead of being 50 x 40mm like the other MiniPiio’s, the MiniPiio_RS232 is 45 x 42mm so its wider and shorter than the others. Being shorter is not a problem just ask Napoleon, but being wider does mean it interferes with the RCA Composite Video connector. 30-seconds with a file cuts it down to size but it does mean back to the drawing board or rather Design Spark PCB.

It was easy to fix, but just means another trip to the PCB manufacturer for another batch of boards. A PDF for the schematics is here.

17 Responses to MiniPiio RS232 v0.10

  1. […] UPDATE: The first PCB’s have arrived see here and heres the first built board ** Like this:LikeBe the first to like […]

  2. samdecrock says:


    Where/how can I get such a board and/or it’s components?


    • zuzebox says:

      The components you should be able to get at most electronic shops.


      U1 – MAX3232 (16-PIn DIL)
      C1-C5 – 0.1uF capacitors
      K1 – 26W-Position/ Double Row 2.54mm Socket
      K2 – 9W D connectot Male RA PCB Mounted
      PCB – MiniPiio RS232

      I’m getting another batch of the PCB’s made so if anyone is interested drop me a line at (remove _at_ and replace with @)

  3. ftaurino says:

    very useful. can you also put the pcb file on this site?



  4. promy says:

    How do you enable this in debian? With me, the ttyS0 or similar does not show up?

    • zuzebox says:

      If you want to use it with your own programs, you’ll need to disable the serial in /boot/cmdline.txt (I think there is another file as well). Search the Raspberry Pi forums for more details.


  5. howard says:


    I’d like this board but do you have any drivers so that can it be used from Basic ?
    I know the old *FX 2 and *FX3 commands currently don’t work from the RISC OS BBC Basic.

    • zuzebox says:

      I’ve not tried BASIC yet but it works find from the OS, wiringPi and Python so it should work under BASIC

      • howard says:

        If you could possibly try it and let us know which commands are used from Basic to direct data in and out of the RS232 board that would be really helpful.


  6. […] Rocrail is using the ddx library to send the commands through the serial port of the rpi. The booster board (ord-3) is powering the test track. Peter Gilling, designer of the board, advised on reducing the value of the resistor R1 – I am currently using 390 ohms- , this is also convinent for usb-rs232 converters. He was also concerned about the rpi being able to generate the signal… This is something that needs further tests… so far, with just one loco and without launching rocview, it seems to work OK. The raspberry has been adapted with a connector to generate the right voltage levels. It is based on this design I found on internet. […]

  7. zxzxzkz says:

    Does this output +/- 12v or does it just do 5v like most USB adapters? Is it possible to get it to do +/-12v if I have +12v and -12v supplies handy? I want to embed this in a machine where there are spare molex power connectors that supply 5v and +/-12v as well as GND.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: