Rewire issues with barcode scanners translating numbers to midinotes

    Mar 18 2011 | 4:58 am
    Hey, I am in urgent need of help here. I have an installation to put up within the next 36 hours and I've brick-walled hard.
    My project consists of bluetooth wireless barcode scanners scanning barcodes into max which are translated into pairs of integers that are used as values for midi messages sent to reason through rewire. (link to the project site:
    The problem I'm having is that after a random interval of time consecutive scanning, reason ceases to respond to the midi signals sent through rewire. I get an error in the max window saying "rewire~ queue stepped on itself".
    I've searched through the forums and came across a couple of other references to this issue. One post ( suggests to use the "good old virtual MIDI buses'from MaxMSP 1' and 'from MaxMSP 2'and assign MIDI buses 'A'&'B' to them in Reason."
    I'm currently running Max 5.1 and Reason 4 on Windows 7 (because the blue-tooth barcode scanners cannot connect to Mac's) . 'from max MSP1' and 'from MaxMSP2' do not appear in either the Max 5.1 midi setup window or the Reason window.
    Any ideas on what I could do to deal with this "queue stepped on itself" issue?
    Here's the patch and attached is my reason file:

    • Mar 18 2011 | 5:42 am
      Never mind guys, fixed it using copperlan virtual midi install for windows 7.
    • Mar 18 2011 | 8:04 pm
      hi there,
      So, your fix was using the "good old virtual MIDI buses" approach, right?
      If you do want to go back and get it working with just ReWire, here's an idea to try. I haven't encountered this "queue stepped on itself" message, but back when I was doing a lot of ReWire hacking, there *was* some weird issue about Reason needing to see periodic "tempo" messages, in order to keep it responsive.
      If you're not running any sequencing in Reason (just using it for sound modules), then easy! Just put this chain feeding the rewire~ object: [loadbang] -> [metro 1000] -> [tempo 120]. (That last one being a message box).
      If you do care about what tempo you're actually telling Reason, then adjust the message you're sending it appropriately.
      Any help?
    • Sep 22 2013 | 7:51 am
      a useful barcode scanner source, share with you, hope it helps.
    • Aug 01 2015 | 3:35 am
      Hi, Clintonzz. Thanks for sharing the barcode scanner with us. I will check it later.