Member #343890

Member Since: August 7, 2012

Country: Norway

  • Great write-up! I have been accessing udev before, for the RTL-SDR, but what is shown here to make the USB-serial devices show up not just as ttyUSB-forever-changing, helped on understanding it. I got an FTDI cable to show up with a distinct symlink, but some of the PL2303-based cables here seem to not show much of distinct values for anything (urbnum and version properties, but even these were the same on two of the cables here). Still, this is nice to know.

  • In the day of the «glass-TTYs» the maximum baud rate supported was 19200. This was the practical maximum for devices such as the 8251A used in VT-100s and several others up through the 1980s. I did some investigations as to why that was, having these niftly little Picotux devices that ran their serial port at 38400.

  • The Wifi and Bluetooth is connected to some other IO lines, and do not share bandwidth with the USB-channels.

  • No header pins installed, and maybe a set of loose header pins included, would seem to be the most flexible option. Depending on what I want to build, I may desire to solder on pins that fit into an IC socket, or maybe I may want to use long pins that stick out both ways, or maybe female header or some male-female combination like what we see on Arduino shields. Or just solder on wires.

    Having to desolder existing pins is always fraught with risk, and it should not be necessary to do that. Having to solder in pins or connectors or wires or whatever happens to be desired right here and now is much preferable.

  • I was wondering about some of the same things, and now that I have one here, I did some measurements. (1) The multimeter showed there is an open circuit (>2 Megaohms anyway) between either of the pins of the plugs and the tip of the sheath, so the sheath is isolated. Thus it may be connected to ground without further ado. The MAX31855 digitizer will be happy and won’t flag the SCG (Thermocouple shorted to GND). (3) The cable from top of the probe to the fitted plug is about 1.75 meters (or 5 feet 8 inches) long, making the entire assembly almost 2 meters from the tip of the probe to the tips of the pins on the plug. (2) This is just my speculation, but maybe the max temperature limit has to do with some kind of plastic parts located in the tip of the sheath where the hot thermocouple junction is isolated – maybe this will melt at higher temperatures?

  • Ah, I’ve been looking around for some small-signal P-channel MOSFETs in TO-92 or similar packages for a while, along with their complementary N-channel devices. Have a couple of design ideas requiring these, and although I have some stock of P- and N-channel devices in SOT23 packages, I still have been on the lookout for some through-hole ones. And here they are.

    The other components are bonus ones to me right now; though the voltage references are also something I would have been looking for sooner rather than later. As for LM317, the 2N3904 and 2N3906 and the diodes, these are generally useful and convenient to have around and available right here.

    Overall, this is an excellent collection of small devices.

  • I have had the wind sensors up on the roof here in southern Norway since December 2012, and they have been working fine for about a year now, in temperatures down to -19 C (-2 F). I did not put the rain sensor up there, as it gets filled with debris from the trees around here, and I have to clean it out occasionally. As it isn’t heated, it doesn’t work below freezing, however, it starts working again once thawed out.

  • Having previously got all his ducks in a row, Jake has now upgraded and put his owls in a row.

  • Weaker and cheaper perhaps, but it is also using less power (1500 mW instead of 3500 mW) so it is a better option when the additional RAM, USB and Ethernet is not necessary.

  • I think the main difference here is that the price of the Raspberry Pi is significantly less than the price of some of the older alternatives. You mention the kit costing almost $700 – and here are the Raspberry Pi for just under $40 – add the power supply and the SD card that are needed and you may have spent something like $70. At prices like that, many more can afford to experiment. Then they post on their blogs or on the forums about what they are doing for everyone else to read and be inspired by. That sort of thing grows exponentially.

No public wish lists :(