Member Since: July 9, 2007

Country: United States



Engineer, experimenter, FAE

Spoken Languages


Programming Languages

C, Assembly


Johns Hopkins, University of Maryland, Virginia Tech


http://www.hazmat.com/matt http://www.hazmat.com/

  • What kind of shock/vibe can this take? IP67- does that mean it is potted? The datasheet/manual don't have any mention other than temperature (operates -25° to 60°C)

  • I have a couple favorites, I've used Metcal at work- nice, and so easy to change tips. For myself, I've given up on ANYTHING that is not temperature controlled- I would consider a butane iron for emergencies, but a temperature controlled iron does everything better. They heat up faster, they are less likely to destroy boards and components, tips last far longer, are less of a fire hazard- they are just better (for any use of your soldering iron that is actually soldering).

  • To be clear "adjustable" does not mean temperature controlled? Temperature controlled is a pretty important distinction.

  • The code isn't that short- according to the configuration bits, everything above 0x800 is code-protected and reads out as 0x0000.

  • When will there be an Autonomous combat robot competition at AVC?

  • I've been working on a display using this and a Microchip PIC32- video of it in operation is here: https://youtu.be/XUCN45TIdpM - the text is generated from an ASCII string and being written to the display via DMA, so it should not be very processor intensive. I've got it in a Github repo https://github.com/MattAtHazmat/PIC32LEDStrip, but it is way out of date right now, as I'm not quite an expert at Git... I messed something up, and I've been spending my time working on the code rather than figuring out Git.

  • I met a gentleman that built turbine controls for model aircraft and drones that used a Microchip dsPIC30. Turbines are amazing, remember to keep the control loop very quick- things can go very badly very quickly, it would be a shame to see this destroyed by a momentary lean condition.

    I am clearly quite envious that I missed this auction- may I ask what it runs for (the turbine sans generator)?

  • Caps over the unused ends of this cable (or shielding) would make virtually unmeasurable changes. The power in the cable in USB is always the same- it isn't affected by speed. Also, the data rate on the cable is not a factor of the serial port speed you're running. To really measure the EMI, you don't really use a scope (you won't see much at all)- you ought to use a spectrum analyzer.

  • Yes, each packet has CRC, but in my experience, most drivers deal with CRC failure horribly. USB just isn't designed to run over a lossy medium. There is no "automatic" downshifting to lower speeds if the connection is poor. It is a statistics game, as long as the vast majority of the packets are good, USB works great, but the overall bit error rate that USB is designed for is something like a single bit error in minutes of operation.

    Diagnosing USB cable problems is miserable- I had a bunch of USB 1.x cables that I ended up just cutting up and recycling because they kept getting into the mix and I'd spend a couple hours diagnosing what I thought was a USB driver problem, but turned out to be a non USB 2.0 cable. (It would connect and enumerate, but eventually fail, and the Windows error messages are particularly un-helpful.)

    The issue is not if the situation is ideal or not, it's a matter of what kind of issues you may be buying yourself into. I'm sure it will work to move data most of the time, but Murphy's law is even more reliable than Godwin's law.

    When space is at a premium, this cable is awesome, and I really see how useful it could be, but USB cables are cheap and pretty small. This very well could find its way into my travel bag (for charging), but I will make it a point that a cable of this type should never be in my lab, except hooked up to a network analyzer as a demonstration of transmission line stub filters.

  • Depending on you you talk to, I could be an expert (or not :). Yes, it might fail CRC, but in my experience USB cable issues are absolutely a pain to identify- USB just isn't designed to run over a lossy medium- I'll think I'll post a reply a little higher in the thread so people don't miss this.

No public wish lists :(