After having an extremely productive day on January 18th, I had a thought: What if every day were January 18th? Well, at the push of a button, now it can!

The button, switch, and display are wired to an Arduino.  The Arduino communicates with a python script running on the router, which controls a Squid3 proxy blacklist.  In SOPA mode, the whole of the internet is my oyster.  In NOPA mode, however, distracting websites like reddit, hacker news, and hackaday are blocked.  This isn’t very useful without a great deal of self control, however.  In weaker instances, nuclear mode must be employed.  Turn the key switch and press the button and all distracting sites are blocked for one hour.  The only recourse is to restart the router, but the router requires 15 minutes to restart, blocking the entirety of the web for the duration.  Overriding nuclear mode is not appealing.

All code is posted online at https://github.com/Zuph/SOPA-Box

A video demonstration and more pictures of construction lie below the break.

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This Saturday, January 21st, there will be a KiCad Workshop from 1pm to 5pm.  Sign up here: http://www.eventbrite.com/event/2696636713.

KiCad is a free utility for designing and laying out printed circuit boards.  Printed circuit boards connect your circuits together without the need for breadboards and jumper wires.  With circuit prototyping services cheaper than ever, it’s simple to turn your design into a real, working board.

This workshop will cover the basics of KiCad, from Schematic Capture, to Board Layout, you’ll walk out of the workshop with the knowledge necessary to take your circuit ideas from dream to reality.

If you’re already familiary with Eagle, KiCad has a number of advantages, including unlimited board size, up to 16 copper layers on your board, multiple sheets of schematic, and more.

Please install KiCad before coming to this workshop.  If you have any problems, or questions, don’t hesitate to let us know.  If you need help installing KiCad, show up early and we’ll try to help you out.

Learn soldering and basic Arduino programming in this workshop. The cost of this workshop also covers the materials cost for a freeduino microcontroller kit. Your assembled Freeduino is yours to keep! Use the vast open resources of the Arduino community to come up with your own electronic applications. This workshop is intended to teach you necessary skills for further exploration in the world of Arduino.

Limited Seating!

More information and registration here!

IT’S TIME FOR A LVL1 MEGA-WORKSHOP!

Sign up now on EventBrite:http://lvl1summercamp2011.eventbrite.com

This summer only, at the LVL1 hackerspace in Louisville, KY, you can learn how to Design, Etch, Solder and Program your very own microcontroller project.

This series of four workshops will take place across every Saturday in June, from 1pm to 5pm.  The first Saturday, you’ll learn how to use EagleCAD to route PCBs for manufacture.  No more perfboard!

The second Saturday, you’ll learn how to use dangerous chemicals to turn a blank copper board into a functional AVR programmer!  With this clone of LadyAda’s USBTinyISP, you’ll be able to program almost ever AtTiny and AtMega chip ever manufactured, freeing you from the surly bonds of the Arduino develoment environment.

The third Saturday, you’ll learn extremely useful skills in prototyping with surface mount components, soldering tiny parts on to the boards you etched the week previous.  Surface Mount soldering is  an important skill, as projects and parts get smaller and more powerful.

Finally, on the fourth Saturday, you’ll learn how to program a CapsLocker, a nefarious device which masquerades as USB keyboard.  This device is capable of entering any key sequence at any interval, super useful for makinG SURE YOUR MARK ALWAYS TYPES LIKE THIIS.  Or p#erha#ps #ann#o#yin# him# in ##eve#n #mo#r#e interes#ting #ways.

If you want to enroll in all four workshops, purchase the four-pack and the four pack only!  If you’d like to participate in just the etching and building, purchase the “Etching It and Soldering It” ticket.  If you’d like to participate in any just the Eagle or Programming workshop, without the fun parts to take home, simply purchase those tickets separately.  If you’re confused, or would like any combination of the above workshops, contact us!

LVL1 members, you get a discount! Contact the appropriate authorities!

Sign up now on EventBrite:http://lvl1summercamp2011.eventbrite.com

After the scrub on the launch pad for flight attempt A, we went back to the books, to try and figure out what we could do to improve our odds the next time around. One of our biggest setbacks was the inability make an antenna suitable for our use: We needed an antenna tuned for 149 MHz, not needing a ground plane, weighing as little as possible.

After 4 tries, and some expensive test equipment, the end result was a Quadrifilar Helix antenna weighing only 80 grams!

Our ground test antenna was a 5/8ths wave whip antenna, which works well, but unfortunately needs a ground plane. Tests with both a quarter-wave dipole and a J-pole antenna were lackluster. Documentation from our satellite service provider implied that a quadrifilar helix antenna would provide the best coverage at all. While these antennas are pretty, their design and construction was voodoo magic at first.

Thanks to some design documentation here: http://jcoppens.com/ant/qfh/index.en.php and some help from the balloon community, we had some baselines for creating such an antenna. We still went through *quite* a few revisions.  We went through 3 revisions that didn’t work, and one which works pretty darn well!

Here are the antennas which didn’t work:

And Finally, this is the antenna that DID work.  This antenna worked 

after we finally broke down and purchased an MFJ Antenna Analyzer.  The antenna analyzer allowed us to very precisely tune the antenna.  A Quad Helix antenna is two full-wave loop antennas, wrapped in a helix, and shorted at the feed-point.  One loop is tuned slightly above the target frequency, and the other loop is tuned slightly below the target frequency.  This affects the circular polarization which makes this sort of antenna exceptionally suited for satellite work.

The antenna is constructed of fiberglass, wood, and music wire.  The central support is 5/16ths inch fiberglass rod.  This is sold in 3 foot lengths at hobby stores as a push rod kit.  Look near the model airplane parts.  The non-conductive cross supports are 1/8th inch dowel rod or bamboo skewers.  The conductive supports are made of 1/16th” music wire, and the helix elements are much, much smaller music wire.  Music wire is spring steel wire, and can also be found in hobby stores, near the model airplanes.

In order to maintain the helical shape of the antenna, it’s VERY important to precisely measure the lateral placement of the supports (where they fall along the length of the rod) and their angle.  It is surprisingly difficult to mark a black fiberglass rod legibly!  The most effective means I found to mark the rod was to take the rod against a 90 degree angled surface, such as a door jamb, and run a file between the edge of the jamb and the rod.  This engraved a straight reference line into the fiberglass rod.  The rod is marked for length, based on the dimensions given in the earlier calculator (with some additional slack for tuning!) divided by 4.  The supports for the long and short loops are offset initially by 1 cm, to give room for the cross-braces to cross paths.

Then, I made a jig to hold the rod and drill holes for the cross-supports.  Using a drill press, I simply made a made a reference hole, then marked the centerline of the hole with a carpenter’s square.  Pilot holes were drill perpendicular to the rod hole by a trial and error method (this is the 3rd iteration of the jig).  Then, angle guides are drawn on the rod hole, to give an angle reference.  This is also done with the carpenter’s square, believe it or not!  It could have been done more precisely with some actual drafting tools, but we work with what we have.

To drill out the rod, the jig is clamped to the drill press, and lined up with the appropriate size drill bit, then the length markings etched into the fiberglass rod earlier are lined up with the appropriate angle marking (they’re lettered, so I don’t make dumb mistakes!)

After all the holes are drilled, the music wire and wood supports are cut to length, and placed in the drilled rod.

At the feed point, the two halves of each loop must be insulated from each other, so the wire is cut in half, and coated with liquid tape before being inserted.  Hot glue provides some structural support here!

In order to solder the helix element wire to the thicker support wire, we had to use silver-bearing plumber’s solder, and plumber’s flux.  You’ll also need one heck of a soldering iron.  At LVL1, we’re lucky enough to have a box full of killer irons.

Unfortunately, only the 260 watt iron here worked! The 120 and 140 watt irons didn’t heat sufficiently to create a good joint.  After about an hour of tuning the antenna, we killed the 260 watt iron, and had to switch to a butane soldering torch (which also worked well).

After soldering each of the connections, it was simply a matter of hooking each loop individually to the tuner, and shortening the length of the loop until it tuned at the desired frequency.  (After some potentially heretical advice, we adjusted the one loop to 149.5 MHz, and the other to 148.5 MHz).  This takes a lot of time, but can be summed up quickly:  shorten each loop by 1cm at a time until you’re there.

Wire the feedpoint as an infinite balun, as shown here:

http://jcoppens.com/ant/qfh/img/v2/012.jpeg

For no particular reason, we also put 4 turns in the coax near the feedpoint.  It can’t hurt.

With all the coax, but without considering the dowel rod you see in the 4th picture, the antenna weighs a stunning 80 grams.  This is under 3 oz!

After configuring both loops, and hanging the antenna in free space, we saw resonance and SWR dip to 1.2:1 at 149MHz.  PERFECT.

In order to test the antenna with the Digi M10 Dev Kit without staying outside, Dan and I rigged the dev kit with a 2mW Xbee Series 2.5 as a wireless serial link.  Now we can be up to 500 feet away while we test our antenna.  This means no more late nights in the parking lot!

Unfortunately, the receive performance of this antenna is not so great.  The satellite beacon signal is around 137 MHz, and our antenna is tuned for 149 MHz.  The modem won’t transmit unless it can hear the beacon signal.  Whenever it keys up, however, those packets fly out.  We’ve never seen any performance like it.

LVL1 is great.  A place for creative and motivated people to get together and goad each-other into doing more creative things.  It’s also a great gathering place for tools, as well as knowledge.  A few months ago, the spoiled electrical engineer that I am, I never would have considered making my own PCBs.  Any project worth taking off the breadboard was worth sending to China to get made “right.”

Of course, there isn’t always time and money to send something to China.  Today’s installment is the Sumo-bot board I’m trying to put together for the Hive13 sumobot competition.  Unfortunately, it doesn’t look like poor Snoopy bot will make it to the ring, but the board making process itself is worth talking about.

Laying out a PCB using software like Eagle is beyond the scope of this post.  If you can follow the appropriate Sparkfun Tutorial, it’s pretty easy to pick up.  Something to note:  for single sided home-made PCBs, put all traces and surface mount components on the BOTTOM layer.  Put any necessary jumpers on the top layer.  When you’re ready to print, just turn off all the layers you don’t want turned into copper.

So, to make a PCB, you’ll need a few things:

• Cheap Photo Paper
• A Laser Printer
• Copper Clad FR4
• A laminator with a straight feed path
• OR a clothes iron
• A sink
• Plastic, non-reactive bowls or tupperware tubs
• Muriatic Acid (Hydrochloric Acid, sold as a pool supply)
• Hydrogen Peroxide
• Acetone
• Nitrile or Latex Gloves
• Baking Soda
• Drill Press
• OR Dremel + Dremel Drill press
• Really tiny drill bits

You can pick all of this stuff up at a hardware or grocery store.  Muriatic Acid is simply HCl, and you can get the stuff for about $8 a gallon in the pool supplies.  A gallon lasts a LONG time.  A laminator with a straight feed path can be had for about $30.  You might have to carve out the back of the thing to allow the board to feed through.  A clothes iron will also work, but you’ll have to be a lot more careful. Copper Clad FR4 can be had at Radio Shack, although they aren’t the cheapest source.

So, let’s get started.  Step 1:

Print your circuit board on the photopaper, shiny side up.

Cut out the design and line it up with your copper-clad board.  Once you have an idea for how much PCB you’ll need, score the board on both sides with a utility knife, and break off the proper amount.  (The proper amount is just slightly larger than your PCBs).

Step 2:

Rough up your PCB under running water.

Use some scotchbrite or something here.  You don’t want to remove copper, you just want to make the surface a little rougher than it was before.  Make sure you rinse off any oil that may have transferred from your skin during handling.  After this step, be careful not to touch the surface of the PCB until after etching.

Dry the PCB thoroughly.

Step 3:

Line up the cut-out photo paper images of your board, and feed the PCB into the laminator.

When you feed the paper and PCB into the laminator, be very careful to ensure that the paper does not slip or slide.  After the first run through the laminator, they will stick to the board, so you don’t need to be careful.

Feed the PCB and paper through the laminator several times, from different angles.  I usually feed through 10 or 15 times.  Careful, the PCB will be very hot to the touch.

If you’re using an iron here, the same rules apply.   Don’t use enough heat to singe the paper, but not much less than that.  Apply smooth, even pressure, and go over the PCB several times.  Be very careful and consistent during this step, or you’ll get unreliable results.

Step 4:

Rinse the paper off the PCB.

First, run warm water over the paper until it is soaked through.  Then, using the pads of your fingers only, rub the paper off the board.  After a few minutes of this, you should be left with the toner only.

Be very careful, and make sure there isn’t a thin layer of paper or glossy film still attached.  This will not etch properly, and will cause bridges.

After this step, you should end up with a board that looks like this:

You’ll notice that there is some residue left over from the paper in this image.  After I took this picture, I soaked the board a little longer, and was a little more careful about removing the paper.

If your board doesn’t look right here, use acetone and wash the toner off.  Then, repeat these steps from the beginning.  Eventually you’ll end up with a board that can be etched.

Step 5:

Mix your chemicals.

Please, exercise EXTREME caution in this step.  These chemicals can badly burn you.  Wear latex gloves, wear safety goggles, and ALWAYS add the Muriatic Acid to the Hydrogen Peroxide, NOT the other way around.

Do this outside, or in a well ventilated room.  Muriatic Acid is not pleasant in the lungs.

Using non-reactive measure cups, mix 2 parts hydrogen peroxide and 1 part muriatic acid.  1 cup hydrogen peroxide and 1/2 cup muriatic acid is plenty to etch a PCB.

In one tupperware tub, I have the acid mixture.  In the other, water.

Step 6:

Etch.

Toss the PCB in the acid bath, and watch the copper dissolve.

As the etch progresses, it helps to agitate the acid mixture.  I simply rock the tub back and forth.  The copper turns the bath lime green.

Here we’re nearly done.  Make sure the copper on the bottom of the board has dissolved, as well.  When all the copper is gone (check between all the pads and traces), remove the board from the acid bath (using tongs!) and dip it in water.  At this point, the board is safe to handle with hands.

When you’re done with the etchant, pour it into a non-reactive container, and keep it until there’s a local chemical disposal day.  Supposedly, you can revive the etchant with some additional hydrogen peroxide, but I haven’t successfully done so yet.

You can neutralize what remains in the tub with some baking soda.

Honestly, I just throw the baking soda away, and rinse out the container, but this definitely isn’t the best way to handle things.  Run the water for a long time, the etchant can corrode your pipes.

Step 7:

Remove the toner.

Rinse the board with acetone, and scrub until all the toner is gone.

You’ll notice some bridges in this picture. At this point, you’ll want to go through with a multimeter, and make sure any suspect portions of the board check out electrically.  You can fix any bridges with a set of dental picks, or an xacto knife.

At this point, you can also square up the board by scoring it with a knife, or using a jigsaw.

Step 8:

Drill.

Using a drill press and really tiny drill bits, drill out your PCB in the appropriate spots.

I’m using a Dremel drill press and some drill bits from Electronics Goldmine.  

In order to avoid breakage, and reduce hole ovularity, adjust the drill press to that it begins just above the surface of the PCB, and stops just beyond the other side of the PCB (adjust press for minimal travel).

Step 9:

Done!

Begin your sumobot exhibition matches as soon as possible.

This Tuesday is shaping up to be a Super Tuesday!  Tuesdays at 8:00pm are our regular meeting times, but this Tuesday, 4/12/11, we’re throwing in a Sumo-bot throw-down, and a Yuri’s Night  Celebration.

What: LVL1 Tuesday Meeting, Yuri’s Night Celebration, and Sumo-bot throw-down!

When: Tuesday, April 12th, 2011

Where: The LVL1 Hackerspace, 814 East Broadway, Entrance on the rear alley

For visitors, our regular meetings usually consist of 30 minutes of talking about LVL1 business, events, and miscellany, followed by building, hacking, making and general mayhem, extending well into the night.  This Tuesday, however, we’ll be celebrating Yuri’s Night, a world-wide party commemorating the 50th anniversary of mankind first slipping the surly bonds of earth, and extending our reach into space.

LVL1 will be hosting members of the Louisville Astronomical Society for some urban star gazing, and we’ll be trying to listen for the ARRISat, an amateur radio satellite currently attached to the International Space Station, transmitting just for Yuri’s Night, before it becomes fully armed and operational later this year.

In addition, almost a dozen members of the LVL1 community have been working on Sumo-bots for the upcoming tournament at Hive13, Cincinnati’s hackerspace.  We’ve got enough bots running around here for our own tournament, so we’ll be doing exposition matches all evening, building, testing and tweaking our sumos!

Come one, come all to LVL1 this Tuesday at 8:00pm.  Anyone and everyone is always welcome.

The LVL1 Hackerspace will be hosting a Surface Mount Soldering

Workshop on Saturday, November 20th, 2010 from 1 to 5pm.  This
workshop will teach you the basics of soldering surface mount
components with a standard soldering iron, using a standard soldering
iron tip.   You’ll be given the tools required to build your own
surface mount projects, and during the workshop, you’ll work on
assembling your own Open Balloon CPU (A design of LVL1′s own White
Star Balloon Team).  You’ll solder 0805 Resistors and Capacitors, 1206
LEDs, and TQFP Microcontrollers, among others.  You’ll learn about the
packages  which can be hand soldered, and the packages which cannot,
along with the techniques required to assemble a working board.

At the end of the workshop, you’ll walk out with the knowledge and
skills required to build any reasonable surface mount project, along
with your own Open Balloon CPU.  These tools include small-gauge
solder, flux, non-magnetic tweezers, and a magnifying loupe.  The Open
Balloon CPU you’ll be assembling is a VERY general purpose sensor
platform, which can be used for a variety of projects which aren’t
related to Balloons or UAVs whatsoever.  Aside from the form factor of
the PCB, everything about the electronics design is generalized for
whatever development the user sees fit.  We will be outfitting the
Balloon CPU with a temperature sensor and Microcontroller, along with
all the passive components required to burn code onto the chip.  If
desired, workshop attendees may add additional sensors (a Real Time
Clock and/or a Barometer) for additional cost.

If you can read newsprint, and have a reasonably steady hand, you can
solder surface mount components!  We will also be doing demonstrations
of hot-air soldering and hotplate reflow soldering, to provide a small
taste of even more advanced soldering techniques.  We can provide
soldering irons, but if you would prefer to bring your own, feel free.
We also recommend you bring a laptop.  If you’ve got an FTDI cable
and AVR programmer, you can start hacking at your balloon CPU
immediately!

For a preview of the skills we’ll be teaching, watch this Youtube
video: http://www.youtube.com/watch?v=3NN7UGWYmBY

Note:  If we do not fill at least 12 seats by November 10th, 2010, the
workshop will be cancelled, and all tickets will be refunded.  Sign up
early, and sign up often!  Any questions, feel free to send them to
bradluyster (at) gmail.com

Sign up early, and sign up often!  Seating is limited.  Buy tickets at eventbrite: http://www.eventbrite.com/event/1000984973

This soldering workshop will take place at 1PM on October, 16th, at LVL1 (814 E. Broadway).  This workshop will bring in 15 Electrical Engineering students from the University, with 5 walk-in seats held for the LVL1 community.  These seats are first-come, first-serve, and the cost will be $10.

Students in this workshop will be soldering together a small variable frequency sound generator based on a 555 timer IC.  Students will learn basic thru-hole soldering skills, wiring components to perfboard.

The IEEE Louisville Student Section is a University Student Organization which serves as a professional and social network for Electrical Engineering students at the University of Louisville.

In three weeks, we went from this

To This

 
 
 
 
 
 
 
 
 
In brief, this board uses the I2C bus to communicate with multiple slave modules and sensors in order to accomplish the task of managing our balloon’s flight.  More information can be found at our wiki.

To fabricate these PCBs, we chose Gold Phoenix, located in Hubei, China.  They offer some really incredible deals on PCB manufacturing, including $100 for a 2-layer board, 155 Square Inches, 5 day turnaround + 3 days shipping.  We chose this fabrication house since Sparkfun uses them for their own products, as well as BatchPCB services.

Much more below the break.

Knowing the Design Limits of the board house, the board was designed with a margin above this.  The $100 service gives you up to 8 mil trace width and spacing.  For this board, most traces are 12 mils, while the remainder are 10 mils.  Most traces have a separation of at least 15 mils, while some are as close as 10 mils.  The ground planes on either side of the board  have a 12 mil isolation from surrounding components and traces.  The text is primarily 66 mils in height, at an 8% aspect ratio, while some pinout text is only 32 mils in height.  If this doesn’t mean anything to you, no worries!

In order to place an order with Gold Phoenix, you simply zip your Gerber files and send an email describing what you need to  a sales representative in Canada.  It’s a little odd sending stuff like this to an arbitrary yahoo.ca email address, but it works out.  A human will be looking at your files every step of the way, so some extra description about how the Gerbers fit together definitely won’t hurt.

When they calculate the number of boards they receive, they divide your project’s size by the board size, in our case, 155 / 6.15.  This yields 25 boards, even though there would be no way to fit 25 of these PCBs on the max panel size of 14.5″x10″.

When I got the boards back from the fab house, they looked like this:

 
 
 
 
 
 
 
I could not be happier at how these turned out.  I was quoted for 25 boards, and received 27. Even the portions of the board which came really close to the fab house’s design limits turned out great!  I can’t spot a single electrical error on any of these boards.  The Silkscreen registration  is a little off on a few boards, although there’s only one PCB for which this may become a problem.

Of course, the first thing I did was solder it together.

The AtMega 324PA TQFP package wasn’t too difficult to solder, and all the programming connections worked perfectly, even though their routing was some of the squirreliest  on the board.

Unfortunately, I can’t say the same about quite a few other properties of this board.  My Cad files had a few errors  on them which weren’t caught before the board was sent for fabrication.  Gold Phoenix faithfully reproduced these errors, and a few components won’t work properly.  The pinout for the temperature sensor was mirrored horizontally and vertically, and the landing pattern for the Real Time Clock on the reverse of the board used an SO16 pattern instead of an SO16 Wide pattern.

Fortunately, this design’s modularity means that neither of these errors are fatal.  The barometer includes a temperature sensor, and timing data can be received from a GPS unit.

In the mean time, the project keeps hammering forward.