Member #134773

Member Since: May 19, 2010

Country: United States

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I started playing with electronics in the mid-1960s, and with computers shortly after Neil Armstrong took “one small step”. I got a degree in CS in 1980, and started working then as an engineer.

  • You missed one of the best features on the Teensy 3.5/3.6: Just add a battery and you have a fully battery-backed RTCC (Real Time Clock Calendar). Combined with the uSD, it can make an excellent stand-alone datalogging computer. The price is more attractive than slower, lower pin count boards that require addition of off-board RTCC and uSD.

  • To some extent, we have a similar background: I first started “tinkering” with electronics about a half-century ago (at about age 12), and with computers shortly after Neil Armstrong took his “one small step” (by volunteering in my high school’s DP department after school). I studied some EE, then math, and then left school for a year working as a tech in an electronics factory, then went back to college and got my CS degree. Spent 23 years working in the chip-building industry, mostly doing specialized compilers for testers (think multi-million-dollar voltmeters), and also “masterminding” some of the “architecture” of them.

    Anyway, I’ve seen a lot change in the last half-century. Much has gone more to computers, and digital stuff. I design several circuits a year, some never get beyond the “solderless breadboard” stage, some get custom PCBs and multiple copies made. The modules available can do some really nifty things, but having a good knowledge of the underlying electronics can both come in handy (e.g., knowing how to use a transistor to drive a relay based on the output from an Arduino, and knowing that you have to have a squelching diode across the coil and why you need it) and make you appreciate the technology all the more.

    Find something that interests you, find some blogs (such as this one) to read (adafruit.com also has some interesting stuff), spend a few bucks on some toys and start playing. You have a leg up in some respects: a volt is still a volt and an ohm is still an ohm. You might pick up a copy of the Radio Amateur’s Handbook (www.arrl.org), even if you’re not into Ham Radio, as it’s an excellent treatise on the more-or-less current “state of the art” of electronics. (Might not be “bleeding edge”, but it’s generally pretty current, and gets updated annually.) Also, check the ARRL’s website for Hamfests in your area. I usually see some folks doing “antique” stuff at most of the Hamfests I go to, if that’s what excites you!

  • FWIW, a lot of Amateur (“Ham”) Radio repeaters are based on Motorola Micor radios that were built back in the 1970s. We use them because they are extremely rugged, can be gotten surplus at very good prices, and are reasonably easy to convert to our needs.

    As Byron said, we really don’t make electronics like this anymore.

  • I trust that you examined the schematic carefully before the “surgery”. Some circuits of this vintage use SCRs rather than transistors to control power to things. Unlike a transistor, an SCR is expecting to see the “load” go through 0 volts to turn off. (Once turned on, an SCR stays on until the voltage drops to [nearly] zero or goes negative.)

    Assuming that’s the case, the only real need for the capacitor in the rectifier circuit is for “aesthetics” – it avoids a 120 Hz (you said you used a full-wave bridge) flicker. It should not significantly impact the life of the LEDs to leave the cap out. (Incandescent lights don’t respond rapidly enough to exhibit a flicker when operating on 60 Hz.)

  • I find it ironic that I was stressing out because of an 11 minute+ video about time stress – I needed to take a shower before a doctor appointment. (I don’t normally have much time stress in my life, being semi-retired.)

    Anyway, as a customer, I’d like to welcome you to SparkFun!

  • The banner at the top of the page says

    SparkFun will be closed for the Thanksgiving holiday from 3pm on 11/23 through 11/27.

    That means you’ll be closed during the entire Black Friday sale. I trust that you’ll have someone monitoring, since nothing can possibly go wrong go wrong go wrong!

  • I’ve just tested the RTCC on a 3.5, and posted my results there. (The “short version” is “it works”.)

  • I’ve now had a chance to play with it a bit. (I had to update my Arduino code to one that will work with Teensyduino.)

    I’ve soldered “header” pins onto a 3.5, and cut a m/m jumper in two and soldered one of the pieces to the Vbat connection. It’s in a solderless breadboard socket, and at the moment, the only wires go to a CR2032 coin cell.

    After a little other tinkering to make sure the system was working, I tried out the TimeTeensy3 demo (which grabs the time from the host computer, and sets the RTCC to that). I then modified a copy, commenting out the setting functions (and adding to the message printed so I know that it’s the version running).

    I unplugged the USB for >10 minutes, and when I plugged it back in, the time corresponds to the Mac’s time, so it sure looks like the RTC is running! EXCELLENT!

  • I had gotten a bit excited when I saw that the nRF52832 Breakout included a 32.768 kHz crystal, but on digging into the data sheet I discovered that the “RTC” is a “Real Time Counter”, NOT a “Real Time Clock”, thus explaining the lack of a “Vbat” connection. Oh well – hopefully I’ll find time to play with my Teensy 3.5 in the next few days.

    Guess it would be a bit much for Shawn’s demo to have used a Pi in the case to talk to one of the Bluetooth-capable products, talking to the other Bluetooth-capable products, in turn connected to Serial Controlled Motor Driver controlling a DC fan… :-)

  • FWIW, the “RTC” (based on the 32.768 crystal) is a “Real Time Counter”, NOT a “Real Time Clock”. (This explains why there’s no provision for a backup battery connection, usually labeled “Vbat”.)

    I’m sure some will still find this board useful, but personally, I have no need for Bluetooth at the moment.

No public wish lists :(