Fun with Interrupts

Something I avoided in college until my senior year was interrupts and interrupt service routines . 

They seemed a little scary.  Interrupts could happen at anything .  The service routines and to be fast and short .  

But they can make life easier and they're what makes multitasking possible .  

There are other ways , but I think a program that keeps checking a pin to see if a dit is still a dit , or if it's turned into a dash, or if some kind of space has happened , and if so , which one , would turn into a large state machine and a huge mess if not planned correctly.  

So , I sketched this out. Again, assuming a normal Arduino and an external audio source and the crude Schmitt trigger interface from a recent post.  

What I don't have worked out is the spacing values for what's a dit and what isn't . 

What's the best way to deal with a bad fist ?  

We shall see...  

A "Mic Check" for the Esplora

The Arduino website has some good sample code .  

I found this bit that looked like a microphone test .  

I haven't tried it yet , but I roughed in a squelch control ....  I think . 

Second Small Arduino Experiment

After getting that first experiment going where we are reading the speaker out line from the Baofeng into the Arduino, we'd move on to working with the Digital input and those Schmitt triggers ...

I don't have any code yet , just this rough but for the comments block . 

Thoughts on an Arduino / Baofeng Experiment

Thinking about how to detect a signal and how to distinguish it from static / noise .  

Luckily , we have A and D inputs on the Arduino. 

I'll have to keep my eyes open at Hamfest for some of these small parts . 

I'll try to write some rough code after Hamfest.  I've got a couple plain Arduinos and an Esplora with an on-board mic. 

NVIS QRP and QRPP style on 40m last Saturday

Last Saturday was a very fruitful "fun" net.  We had 5 participants from the Tulsa/Broken Arrow area, Collinsville,  Yukon, and even Dallas/Fort Worth.  All on PSK31, with a change to Oliva 8-500 for good measure.

N5PT gave the most complete signal reports.  He was running 5 watts and I consistently copied him at 21 db at my location on PSK31.  The rest of the reports below are for Olivia 8-500, which will usually be a full 15 db lower due to its broadbandedness compared to PSK31.

Tim KG1GEM out of Dallas was between -6 and -9 db, but 90%+ copy.

Scott KD5NJR was 1.9 db at 5 watts and then dropped to -2 db at 1 watt.  Great copy.

Scott KC5SHE was -12 db and had the least copy of the group.  However, Jeff 5ME (Broken Arrow) was able to copy Scott at 24 db on PSK31 and could have easily relayed to N5PT or KG1GEM if necessary.

Like Scott KD5NJR stated, 1 watt between his location and Collinsville would be impossible on 2m or 6m.  Definitely out of the question to OKC or Dallas.  But he was having a blast running 1 watt on 40m NVIS.

We're going to do the "fun" net again this upcoming Saturday (February 28th) at 2:30 PM on 7036 kHz with a center frequency of 1500 Hz.  We'll start out on PSK-31 and adjust from time to time.  TxID will be used to make sure stations know what is the current mode from net control.

Weekend Hammin' de Scott KD5NJR

Had the opportunity to play some "Ham Radio" Saturday late-morning / early afternoon with Steve KE5URG. 

1) Showed him how to set up his Buddipole.  ie: using the included table to pull out the right amount of telescoping whip and make the right tap settings.

2) Showed him how to use his MFJ Versa-Tuner's cross needle SWR meter and tuner controls to find a good tuner solution.  This is where FLDIGI's TUNE feature lets me get both hands on the tuner instead of worrying about whistling into the mic while holding the PTT down.


3) After feeling good about SWR, worked a couple 10m European DX (The Netherlands) stations.  One on the 817 and one on Steve's Ten-Tec Scout.


4) Switching to 20m module on the Scout; worked the Titan Missile Museum WE7GV and a ice fishing shack on frozen Goose Lake in Minnesota.  Temp in ZIP 74012 :  72F.  Temp at ice fishing QTH : 0F.


That Buddipole antenna is a lot of fun.


73
Scott
KD5NJR

Radio Shack

How did everyone fare as the Radio Shack's closed down ?  I grabbed some pretty good deals.  Mostly on little sensors and stuff for the Arduino / BasicStamp class microprocessors.  -- Scott KD5NJR