USB connection lost shortly after starting a roast

I’ve been seeing something unusual and wanted to check to see whether anyone else is encountering a similar issue.

About 30 seconds after drop, Roastime reports that the USB connection is lost. If I quickly unplug and reconnect the USB cable, Roastime detects the roaster and everything is fine, save for a little step in my roast curve where the software was not receiving data from the roaster.

If I had to guess, it’s been happening about 2/3 of the time, going back around 4-6 months.

I haven’t tried swapping USB cables yet but I think I’ll do that on the next roast. I’d think if it were really a cable issue, the problem would tend to recur throughout a roast.

As a tangent, it might be nice if the data logging between the Bullet and Roastime were such that the missing time were accounted for in the roast profile. The step I see in the roast curve suggests that Roastime is using its own time base when handling the samples from the roaster, rather than using elapsed time data from the roaster. If it were, it seems that glitches like this could be represented as a missing data segment along the x-axis of the roast graph.

My config:
Bullet v1.5, 110V, SN 1578, purchased 2/2019.
FW 541 (?, whatever the latest production release is)
RT 2.5.5
MacBook Pro, MacOS 10.14.6

This may not apply as I use the Win 10 version of RT 2.5.5.

There was an issue with comm for Bullet <–> RT several months back which seems to have been resolved (I think!) in the Win 10 version. What I can’t recall is which f/w & s/w versions were involved. I’ve been using f/w 553 (beta) without issue since it came out a couple months ago.

And of course there’s always the blind hope approach of reinstalling both f/w & s/w. Sadly it does help sometime,s especially if you’re having an issue with comm!


Thanks, Bruce. I’ll try switching to the beta firmware on the next roast and see whether that addresses the problem.

I had to give up on one of my macBook Pros with the Bullet - it just wouldn’t stay connected. Fortunately, I had a much older macBook pro handy, and it’s been working great. I think Apple’s USB is near one end of the spec, and the Bullet’s is at another. I’ve had issues with macOS and USB on other devices - it’s frustrating.

I’d surprised if it’s a hardware issue, given the repeatability. The connection drops at exactly the same time after the start of each roast, and then stays connected from there on out. I did a back to back session last night and the drop happened during the first roast but not the second.

Have yet to try a different cable and/or port; I’ll do that next roast if I can remember…