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bluehash

What are you doing right now..?

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Building up my wireless sensor boards.  It's basically a miniaturized fraunchpad with a 900MHz xbee radio that runs off of a single cell LiPo battery.  The current design lets it mount a CC2541 sensor tag as a daughterboard (shown in the pics).  Was hoping to have it running today, but I ordered the wrong size comparator (MS8 instead of S8).  

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As much as I despise Solaris, the "tip" command was rather nice. I just use minicom under linux but even it uses the fullscreen-terminal ncurses library.

I don't mind minicom, but I need something a bit more special-purpose.  I suspect it will want to have a GUI someday, but since the meat of it is POSIX C, all the GUI needs to be is the GUI.  That is the only way, I've found, to allow a good degree of independence of platform, independence of library version (I'm looking at you, Qt), and independence from having a damn terminal app that is a 36MB application and eats 100MB RAM.

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Just got schooled on the ins & outs of fprintf() et al.

 

Apparently by default, when you allocate a stdio handle it enables full buffering, so fprintf() won't show anything... until you run fflush() on the handle.  There's a setvbuf() call that lets you set the buffer (full or line-buffered, where newline triggers an auto-flush) and/or change it to non-buffered mode.

It seems like printf() must issue fflush() automatically at the end of each execution though, so you never see anything wrong when the filedes is STDOUT_FILENO & you use printf() to output, but if you assign the output of fopen() to a FILE ptr and use fprintf() on it (even though it's supposed to be the same as stdout), that fprintf() won't show anything automatically.  Had me confused for a bit.

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I'll start. 

I have a Baofeng UV-B5 radio($30) that I use as a scanner and listen to hams in my area. My model comes with a flash flight button which is disabled, but used on a similar model. I came across this link to connect that button to control the LCD backlight on/off, which is great, so I can see the screen at night, and consumes only 10ma.

 

attachicon.gifbaofeng_uv-b5-flashlight_mod_bacllight_lcd.JPG

Success!

 

I just bought a Baofeng UV-5RA to monitor until I get my license.  Great little unit for $30!

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Playing Hay Day.                           And regenerating for new and exciting year.

 

 

Oh, and trying to make enough money to buy this thing (you MUST read reviews.)

Wow! :ohmy:

 

@@RobG , How about one of these instead?  The screen is a little smaller....but still... :laugh:

 

http://4gte.com/tektronix-dpo70404c-4-channel-4-ghz-oscilloscope.html

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Oh, and trying to make enough money to buy this thing (you MUST read reviews.)

Should go alright on a pi, but where's the challenge in just plugging in a hdmi cable? Who's up for hacking an interface then writing an Energia library?

 

 

Sent from my iPhone using Tapatalk

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I have a Baofeng UV-B5 radio($30) that I use as a scanner and listen to hams in my area. My model comes with a flash flight button which is disabled, but used on a similar model. I came across this link to connect that button to control the LCD backlight on/off, which is great, so I can see the screen at night, and consumes only 10ma.

 

I just bought a Baofeng UV-5RA to monitor until I get my license.  Great little unit for $30!

 

Seems to sell like hotcakes, the UPS man just dropped a Baofeng UV-5R+ on my doorstep :) I hope to use it as a test signal  to fiddle with my AIS project. (Carrier signal only, I don't think it is able to transmit data)

 

Besides that, I successfully put my $2.50 reflow oven into production. No more handsoldering of QFNs.

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Heat 0.25" aluminum slab to 160C (gently, it should be stable at 160C or only slowly increasing), add aluminum tray with PCB and temperature probe inside, cover with 2nd tray, wait till PCB reaches 160C plus another minute or so, turn up the stove to max, wait till PCB reaches 220C, take tray off the stove and let cool, season to taste.

 

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Saw chicken's dAISy project. Thought it was cool.

 

Ordered this $10ish RT2832U DVB-T USB stick from dx.com, came in 3 weeks. Install gnu-radio, rtl-sdr, gqrx and dump1090.

 

Now watching planes over my house.

 

I am inside and using the stock antenna, can capture at most half a dozen planes.

Will build an elevated outdoor antenna when it's warmer. Should catch tenths of planes.

 

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Links, details?

 

There were a few posts in HackADay, DP, etc mentioning the use of such DVB-T sticks as SDRs. I was following links to links and understand it can also receive ADS-B, which is similar to the AIS (chicken's dAISy project) but instead of boats, it's for planes, I leant.

 

Basically you need to get rtl-sdr, which expose these DVB-T sticks w/ the RTL chipset for use as an SDR. dump1090 is a script front-end that make use of rtl-sdr to get the ADS-B 1090Mhz signal and decode it. It also has an option to visualize the data via google earth (served via port 8080).

 
The gnu-radio, gqrx are for other fun activities like spectrum scanning and such.
 

There were various info out there but this is by far the most straight forward for plane plotting.

 

http://oh2fxd.wordpress.com/2013/10/15/building-a-complete-adsb-receiver-unit-from-a-to-z/

 

This link mentioned the use of a dedicated system-on-usb run the own set-up and has the advantage of (1) 24/7 streaming of flight data, (2) system can be attached at the base of antenna outdoor for best reception.

For myself, I am running it off a ubuntu / mint netbook.

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