New England Radio Discussion Society summary

Discussion of upcoming radio events.

New England Radio Discussion Society summary

Postby AI2Q » Wed Nov 30, 2011 5:01 pm

Hams attending last night's meeting of the New England Radio Discussion Society were treated to a great presentation by AB1PU. Tom played a brief video showing the folks involved with the advent of the Arduino microcomputer platform, and he also brought his own Arduino board and PC for demonstration purposes.

Tom's hands-on demo and show-and-tell included a brief description of how the Arduino integrated development environment worked.

To everyone's delight, he then showed samples of his coding, winding up with running a number of basic Arduino programs. One generated a Morse output signal that followed the text that was input to the Arduino system. Quite nifty.

One thing Tom was cautious about was not letting his Atmel AVR microcomputer output pins deliver more than 2Ø milliamperes (2Ø mA) to his speaker load or LED load. He didn't want to smoke the chip.

This got me thinking about how NERDS folks can start to connect the dots. Think about it: with one or perhaps two resistors and a 15-cent 2N2222 bipolar transfer resistor (aka transistor), Tom's current-constrained output pin could easily drive a big loudspeaker, or perhaps key a large relay coil which could, in turn, perhaps key his rig or flash a honkin' big 25Ø watt light bulb in time with the CW rhythm. Alternatively, the output pin on the Arduino chip could key a big solid-state relay or triac. The possibilities are endless....

You could use your knowledge of Ohm's Law and how a transistor works to draw the schematic for this, and determine the values for the parts, and poke the parts into a prototyping board like the one we used for setting up the transistor amplifier, or the one Tom uses for his input/output (I/O) experiments. Looking at the manufacturer's data sheet for the transistor and the Atmel chip would help us learn more about schematics and mechanical and electrical specifications, too.

Show-and-tell, anyone?

Because we're essentially limited to about two hours time per NERDS pow-wow at the firehouse, we never got to the show-and-tell portion of the meeting. Nonetheless, there were a number of interesting things NERDS folks brought along.

These things were quickly looked at before everyone had to head out the door, but they deserve more time and explanation.

N1YQV, Harvey, for example, had three interesting, albeit timeworn, illustrated books about antique radios.

K0ZK, Arn, was packing a ultra-low power digital synthesizer kit that he intends to embed in a VFO for QRP applications. Arn's kit uses the direct digital synthesis (DDS) technique based on an Analog Devices Inc. DDS chip married to an Atmel microcontroller.

AI2Q, Alex, brought along his miniature rendition of the PIC microcontroller-based Norcal software frequency counter.

To beat the band, KB1GTT, Jared, whipped out a pocket -sized 10-MHz oscilloscope that was no bigger than an iPhone smartphone. His tiny color o'scope had no fewer than two analog input channels and two digital input channels, and even packed a built-in signal generator! What a revolutionary age we live in.

Here's my suggestion: How about we do a re-do of last night's hasty last-minute show-and-tell for our next NERDS meeting on December 13th?

W1SLP, Pete, for example, has some fine examples of yesteryear's test equipment that can reveal how things have changed. W3NA, John, a DX Century Club Honor Roll member, has one of the most extensive foreign DX QSL card collections this side of the border. For his part, AA1LO, Dave, has some great QRP rigs built from kits, as well as station accessories he has built. N1UE, Darden, has a unique electronics course that's based on a QRP transceiver kit. The list goes on ...

I'd be willing to bet we could all dig up some interesting Amateur Radio item to show-and-tell.

Please use this reflector to let everyone know how you feel about this idea for our next meeting.

I look forward to seeing comments. Until then, very 73, AI2Q, Alex, Member: ARRL, FOC, RSGB, CWops, QRP-L, Antique Wireless Association, Wide Area Amateur Radio Network, New England Radio Discussion Society
http://home.roadrunner.com/~alexmm
AI2Q
 
Posts: 168
Joined: Thu Oct 20, 2011 11:36 am

Return to Events

Who is online

Users browsing this forum: No registered users and 2 guests

cron