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.

.

Signup at EventBrite http://www.eventbrite.com/event/2562787366

After the popularity of Butterscotch I seem to have got a reputation for adding fire to things (even though it was FireTim that did the pyro half of Butterscotch).  So when the Mythbusters posted a link to a fire breathing pumpkin I was bombarded with questions about when I would be building one.  Not being the type to do what others expect me to do I rejected the idea of doing a pyro pumpkin outright.

Though I was set on not building a fire breathing pumpkin it did make me think about building other things inside of a pumpkin.   Then it hit me just two days before Halloween. I needed to build a pumpkin that would forcefully deliver candy to Trick-or-Treaters much in the same way they would deliver eggs to my house if I did not provide candy to them.  From that point on I had a mission. Throwing sleep and other responsibilities to the wind I went to the bowels of the LVL1 bone yard to hack together a candy launching pumpkin.

After design concessions due to time and help from fellow LVL1ers (thanks FireTim and Jon the Kilted) I was able to defend my house this year.  Although I never saw the pumpkin Mythbusters link and I am sure it is cool I considered this a spite project similar to JAC 101 Micro-Laser Cutter.  I just hope everyone enjoys it as much as I enjoyed making it.

I have posted an instructable for this project to help others defend themselves next All Hallows’ Eve… but really, why wait.  Go to that instructable and start defending yourself for Thanksgiving, Hanukkah, or Christmas.  There is nothing like a fruitcake chucking Santa to keep those damn carolers at bay.

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

Well here is your chance! LVL1 is raising money to buy a laser cutter for the space. With a laser cutter you can do all sorts of neato things like this…

http://www.epiloglaser.com/sample_club.htm

Scroll thought the link and think about what you want to make. Then donate to the laser cutter fund. The sooner we make it to $2500, the sooner we can get a laser cutter for all to share. IT IS GONNA BE SO AWESOME!

Here is the Laser Cutter we are going to buy.

http://www.fullspectrumengineering.com/co2laserv2-40w.html

and a video of it in action…

As you can see, you want to give to this fund! Watch the progress bar on the right side of this blog to see how much further we have to go!

By using the donate button below you will be taken to Paypal to make a donation to the laser cutter fund. When you use this button the donation is earmarked for the laser cutter fund, not the general fund.

DO IT FOR THE DINO!

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.

We are having a Car-B-Gone workshop at the space this afternoon. Sorry we did not get the Eventbright announcement up. Just show up to build your very own Car-B-Gone tonight at 8-ish. If you do not know what a Car-B-Gone is… it is another fine Mitch Altman project. Read about it here

Following the Car-B-Gone workshop will be the ever popular Beer-B-Gone workshop. Hope to see everyone there.

Brian