[Noisebridge-discuss] arduino dmx receiver

Phillip Pearson pp at myelin.nz
Thu Mar 31 22:40:36 UTC 2016


Thanks!  The boards are my own design -- an ISO3088 chip plus isolated
DC-DC converter, and Neutrik connectors.

I can confirm that the DMX code out there for Arduino and friends is a bit
flaky :)  As Mitch says, though, DMX code written for the Duemilanove
should work fine on an Uno, because it uses either GPIO or HardwareSerial;
the FTDI chip isn't required.

I haven't tried receiving DMX on an Arduino, but I've implemented DMX
reception on a Freescale KE04 ARM chip, and it's not super hard.  The only
tricky part is that the DMX packet starts with a 'break', where the data
line is held low for ~50 us (12.5 bit times).  This will show up as a
framing error, and is probably what you need to edit hardwareserial.cpp
for.  I won't have time for a few days, but when I get these boards up and
running I'll see about hooking one to an Arduino and testing out some
receive code there.  I've been using a Teensy and a USB-DMX adapter
(Chinese uDMX clone) on the sending side so far.

Cheers,
Phil


On Thu, Mar 31, 2016 at 1:56 PM, robb <sf99er at gmail.com> wrote:

> thx for the responses
>
> @PhilIP nice boards! (your pic rendered) are those mathertels?
> my usb>rs-485(dmx) adapter/converter has 3 connectors (grd, D+ & D-) which
> connect to a neutrik xlr panel connector (see attached).
>> @Mitch although there are lots of posts/pages describing how to code dmx
> on arduinos, most of the work has been done related to transmitting dmx
> (mostly on pre-uno versions, which are very hard to find) and not receiving
> it. the few libraries for receiving dmx are quite old & don't seem to be
> very straight forward, i.e. require editing hardwareserial.cpp at a keyword
> that does not actually exist in the file (ArDMX).
> thanks for the invite to hhn. food not bombs just brought me a wheelchair,
> so i might be able to take you up on it soon.
>
> cheers
> ~r
>
> lulzlux - ASK (Activist Support Krewe)
>
> On Thu, Mar 31, 2016 at 1:32 AM, Phillip Pearson <pp at myelin.nz> wrote:
>
>> I sent the following response but it may have gotten rejected by the list
>> software because of the embedded image:
>>
>> I've been working on DMX stuff for a little bit... have been soldering up
>> DMX interface boards at NB tonight, in fact!
>>
>> [picture of DMX boards removed]
>>
>> Is your FTDI to RS485 adapter designed for DMX output -- i.e. on one end
>> it has a female XLR connector that would plug into one of the boards above?
>>
>> Can you email me a photo of your setup so I can get a better idea of how
>> the RS485 modules are wired up?
>>
>> Cheers,
>> Phil
>>
>> On Thu, Mar 31, 2016 at 1:18 AM, Mitch Altman <maltman23 at hotmail.com>
>> wrote:
>>
>>> Hi Robb,
>>>
>>> If you don't get an answer here, try searching for "Arduino DMX" you'll
>>> find plenty that people have worked out.  Also, please come to Circuit
>>> Hacking Monday, every Monday at 7:30pm, where people help each other with
>>> everything hardware.
>>>
>>> Cheers,
>>> Mitch.
>>>
>>> ------------------------------
>>> From: sf99er at gmail.com
>>> Date: Wed, 30 Mar 2016 21:35:49 -0700
>>> To: noisebridge-discuss at lists.noisebridge.net
>>> Subject: [Noisebridge-discuss] arduino dmx receiver
>>>
>>>
>>> hey gang,
>>> anyone know how to code an arduino to receive dmx and output pwm to
>>> leds? i think i've tried everything on the arduino site's dmx page but
>>> nothing seems to work.
>>>
>>> my setup is qlcplus > ftdi to rs-485 adapter > ttl to rs-485 module >
>>> arduino
>>>
>>> i will come sweep, mop & dust noisebridge, when my broken foot heals, if
>>> someone can point me in the right direction.
>>>
>>> thx for being there
>>>  ~r
>>>
>>> _______________________________________________ Noisebridge-discuss
>>> mailing list Noisebridge-discuss at lists.noisebridge.net
>>> https://www.noisebridge.net/mailman/listinfo/noisebridge-discuss
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>>> _______________________________________________
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>>>
>>
>
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