Member Project of the Week: Hacking a bargain LED lantern

I’ve often found there’s always a bit of “Tim the Tool Man Taylor” in every hacker.  That is, we all endeavor to make something bigger, badder, and more powerful than anything in it’s class.  Such is the thinking behind this project.  My Mom is an avid shopper, and she is often finding all sorts of bargains.  This time around, she found a camping LED lantern, with 12 LEDs, and a marked luminance of about 30 lumens.

1_first_impression

When I took it out of the box and powered it on, the light was adequate, but not for an LED freak like myself.  Furthermore, I don’t know who designs these things, but they obviously don’t test their own creations.  The lights were mounted facing up, reflecting off a hyperbolic cone.  Unfortunately this means that the majority of the light would be shining out from horizontal upward into the eyes of anyone near it.  As well, none of the light went onto the surface the lantern was sitting on.  These two aspects rendered it quite useless as lanterns go.

2_better_look_at_reflector

Seriously, who designed this and didn’t test it?

My mom was a bit disappointed that she apparently didn’t find as good a bargain as she thought, but I reminded her that with a bit of elbow grease and a few cheap components, I could make it better.  You see, the hardest part of making a good lantern isn’t the light engine, it’s the plastic housing.  The ones she bought already had what I considered to be a pretty nice plastic housing, it just needed an upgrade of the light engine.

Analysis

3_there_is_space

On opening the battery compartment, I noticed that there was some space in it for extra electronics.

4_there_is_hope

Red arrow shows extra space untouched by the 3 D-cell battery carrier.

Knowing that white LEDs run at a forward voltage of 3.4v, and wanting to not use any type of resistive regulation (to avoid wasting power as heat), I knew that A) I’d either be stepping the voltage down to 3.4v or stepping it up to whatever LED cluster I found.  That meant that i needed space in the lantern somewhere for a regulator.  This little nook had enough volume for many switching converter designs, I just needed to find one to fit it.

I immediately went looking on eBay for LEDs to use, and happened upon a lot of 5 of these aluminium core boards that have three 110 lm LEDs on them.  They’re wired in series for a combined brightness of 330 lm. I picked them up for $8.  However, because they’re three 3.4v LEDs wired in series, they’re rated for 10.2v (the post said 9-12v, but 10.2v works the best).  The lantern has a battery carrier that holds 3 D cells.  This gives me an adequate amount of amperage at 4.5v.  Not enough voltage to directly drive the LEDs, so this meant I definitely would need to buy a boost controller.  Again, eBay serves it’s purpose and I was able to nab these LM2577 switchers for about $2.85 each.

5_components

 

Beginning disassembly

5_begin_disassembly

Whenever taking anything apart, make sure you note which screws you pulled from where, and make note of any type of hardware keying like you see here.

6_pay_attention_to_keys

Note the red arrow pointing to the key and slot that the designers put in the top. Make sure you keep track of this for later…

When I cracked this open, I discovered that the hyperbolic cone was not glued to the top (bonus!), but would require cutting if i was going to attempt to put it in the bottom (bogus!).

7_in_elemental_pieces

Elemental pieces. Now it’s time for checking if we can invert the cone.

I centered the hurricane “glass” of the lantern on the cone, then used a fine tip sharpie to draw the outline of the bottom of the glass.

8_testing_fit_drawing_circle

Checking the fit, tracing inner circle with fine tipped sharpie.

9_line_on_reflector

Cut line now marked with fine tip sharpie.

 

I cut relief cuts into the circle before attempting to cut the full circle.  This makes it easier to snap off the chunks as you cut them.  Cutting a circle with a rotary blade on the dremel isn’t easy. To make it easier, I put the dremel in a vise so I could maneuver the reflector around the blade rather than the blade around the reflector. Note my use of the blue nitrile gloves.  When handling any type of chromed plastic reflector, you’ll be sorry if you don’t use gloves.  Once smudged with skin oil it’s hard to impossible get them back into a clean state without scratching them.

10_relief_cuts

Cutting relief cuts before cutting along the sharpie line.

11_test_fit_a

Testing the fit.

12_test_fit_b

Testing the fit with the hurricane in place.

 

13_glue_down_reflector

Gluing down the cone to the bottom reflector with 2 part epoxy.

As with all higher luminance LEDs they emit a fair amount of heat, which is dangerous for the life of the LED.  They do much better if you attach them to a heatsink.  Junk bin to the rescue! CPU heatsinks are useful for many high power LED projects, and they’re usually free if you can find an older computer to scrap.  This heatsink had two “wings” out from the fan, one of which I’ve already removed with a hacksaw to use for this hack.

14_cpu_heatsink

Soldering to the aluminium core board is a hassle, precisely because it’s efficient at wicking away heat.  It means you have to dump a lot of heat into the joint just to get it to marginally flow.  I’m not happy with the quality of these solder joints, but they worked.  Oh, and if it wasn’t obvious, solder FIRST, then attach heat sink otherwise you’d never get solder joints to flow.  ;-)

I added thermal grease between the heatsink and board, and secured the two together with some dabs of epoxy around the edges and holes in the board.

16_assembled_led_head

I had to remove the switch and battery contact board in order to wire it up to the new driver board.

17_salvage_button_and_contact_board

I soldered it inline with the regulator.  At this stage, I made sure to adjust the output to match the LED forward voltage, in our case, it needed to be adjusted to 10.2v out.  Since these boards are adjustable, you need to attach the voltage you’ll be working with to the input, and adjust the trimmer pot while watching the voltage on a multimeter.

18_add_boost_regulator

If you don’t have this in your hacker’s toolbox, go get some.  Epoxy putty is invaluable, as much for being a filler as it is for being an adhesive.  Be sure to use gloves when kneading it though, as it gets sticky and you don’t want it on your skin.

19_lovely_epoxy_putty

Here you can see the two blobs of the putty that are used to attach the LED assembly to the top.

 20_attach_led_assy_to_top

 

Drill a hole in the back of the reflector to thread the LED head leads through to the battery compartment.

21_make_way_for_leads

Threaded the leads down into the battery compartment as I reassembled the top of the lantern.

 22_thread_leads

 

Here’s where final steps of putting the circuit together take place.

 23_assemble_power_circuit

 

The power board I bought just happened to fit into the switch area without needing to remove any of the plastic.  I always appreciate those little coincidences.

24_final_assembly

The final product, reassembled.

25_reflector_comparison

And finally the two versions side by side.

Two final versions lit up.

26_illuminated

Conclusion:

All told, the entire mod for the first lantern was around 3 hours for a price of about $6 ($1.66 for the LEDs, $2.85 for the boost controller, and about $1.50 in epoxy and epoxy putty). The time spent on subsequent lanterns was about 1 – 1.5 hrs each, now that I know what I’m doing with the design.  Not too shabby.

So did I save any money over buying a higher lumen lantern that was already built?  Yes, and no.  Yes, in pure dollars.  No in terms of time.  But if you don’t understand why someone would spend the time hacking something that might be easier to buy, consider these points.

Hacking something provides:

  • the pleasure of the challenge to make something better.  It gets the creative juices flowing as you attempt to solve problems.
  • the time spent tinkering (far more relaxing than vegging out in front of the TV, IMHO)
  • the feeling of accomplishment when it works and learning from failure when it doesn’t
  • learning how to do things better when you hack on future items
  • it can push you to learn new technologies and techniques in order to get what you want out of the hack
  • the option to actually have a “good enough” approximation when the desired item doesn’t exist, or is prohibitively expensive if it does.
  • prototyping a new idea based on the initial item

And most of all, sometimes you don’t know precisely what you want, until you’ve hacked it!

 

Bitmessage and Tahoe-LAFS at Crypto and MeshNet Meetup

Little MeshOn Wednesday, August 28, the Solid State Depot had crypto and meshnet meetup with lightning talks, general discussion, and installation for Bitmessage and Tahoe-LAFS.

Ben Burdette started off the meetup with a presentation on Bitmessage. Bitmessage is a P2P communicationns protocol used to send encrypted messages to another person or to many subscribers. It is decentralized and trustless, meaning that you need-not inherently trust any entities like root certificate authorities. It uses strong authentication which means that the sender of a message cannot be spoofed, and it aims to hide “non-content” data, like the sender and receiver of messages, from passive eavesdroppers like those running warrantless wiretapping programs.

Zooko talked about Tahoe-LAFS.  Tahoe-LAFS is a free and open cloud storage system. It distributes your data across multiple servers. Even if some of the servers fail or are taken over by an attacker, the entire filesystem continues to function correctly, preserving your privacy and security.

Aspects of Tahoe-LAFS of interest at this meetup:

  • LAFS cryptography: Public/private keypairs are per-file, not per-user, digital signatures are everywhere, public-key encryption is not used, secure hashes and merkle trees are a beautiful data structure, akin to git.
  • The open source project: We have dozens of hackers from around the globe extending LAFS in different ways ; Want to contribute? We use a development process with complete unit test coverage and mandatory code review on all patches. We are nice. We have weekly meetings. Join in!
  • Usage: How to get the source, build it, deploy a grid of storage servers, share files and directories with your friends; who runs storage servers and gives you access to their storage server—friends sharing storage space with each other? Strangers meeting in the darknets? You can lease storage from my for-profit startup.

See more about this event on its Meetup.com page.

Machine Learning Meetup

Machine Learning Survey MeetupAt the machine learning meetup on August 18th, 2013, topics covered introductory basics leading up to basic support vector machines and basic artificial neural networks. Various applications of machine learning were covered, such as beating experts at wine tasting, predicting housing prices, predicting which products from a chip manufacturing process will pass testing, doing optical character recognition (OCR), email classification as spam or not spam, reducing color palettes in images, detection of anomalies in a manufacturing dataset, and how to make a movie recommendation system. Based on the Coursera/Stanford course by Andrew Ng, who used machine learning to teach model helicopters to fly stunts.

Raspberry Pi Roadshow

Raspberry Pi Roadshow (August 14, 2013)

Rob Bishop, an engineer and evangelist for the Raspberry Pi Foundation, stopped by the Solid State Depot Boulder Hackerspace as part of the Raspberry Pi United States Roadshow! Rob’s talk “Raspberry Pi — One Year On” covered both the origin story of the Raspberry Pi as well as outlining recent developments. The talk presented technical information about the Raspberry Pi alongside a discussion of the Foundation’s educational aims. After the presentation, there was an opportunity for an in-depth Q&A on both educational and technical matters.

We basked in the glory of the useful little microcomputer known as the Raspberry Pi!  Useful for education, hacking, productivity, and even playing games like Quake 3 Arena—rather nice for low-cost computer! Several people brought their Raspberry Pi related projects for show and tell—including a digital music keyboard synthesizer and a MAME (Multiple Arcade Machine Emulator) system. See the event listing on Meetup.com for more information.

Raspberry Pi Roadshow 2013

Fix-It Clinic with Eco-Cycle

Volunteers of the Solid State Depot Boulder Hackerspace, along with Eco-Cycle, coached and assisted citizens of the Boulder, Colorado area in need of electronic equipment repair as part of the Fix-It Clinic event on Sunday, August 11th.  By not only helping fix, but also helping teach and educate by demonstration, the Solid State Depot volunteer fix-it coaches aided those from the community in the process and approaches required to fix their appliances instead of throwing them out.

The Fix-It Clinic coaches repaired appliances vacuums, toasters, two blenders, a scanner, and various other appliances.  Of note was a broken plastic part for a blender.  To replace it, Solid State Depot member Rob Bryan rapidly, algorithmically defined and modeled a replacement part using OpenSCAD, and then Bryant Hadley handled the 3D printing of the modeled part at the hackerspace.

Replacement Part Modeled in OpenSCAD

Replacement Part Modeled in OpenSCAD

This is even more recently relevant, since last month Colorado followed suit with 19 other states and banned the dumping of electronic waste into its landfills. Notably, the health risks associated from heavy metals from various electronics potentially escaping out of the landfills and into groundwater has prompted this movement.  There are electronic waste handling facilities, but the processes required to recycle the electronic equipment can also be rather toxic. Thus, by repairing instead of disposing, we reduce the negative impact upon our environment.

3D Printed Blender Replacement Part

3D Printed Blender Replacement Part

Facilities such as the Solid State Depot offer an important venue in the community — allowing people to get together and have access to tools and resources for tinkering, creating, making, and repairing that are often collectively too costly and take up too much space for most individuals to have all in one spot. In the end, fun and excitement was had by all in the exploration and discovery of the household devices around us all.

Workshop Weekend

Howdy Hackers!

Another great Saturday at SSD. The number of the day is 2.

We had 2 workshops today, an FPGA class (more info and photos to come) and we now have our second 3D printing graduating class from the 3D printing workshop 2.0  – We also get to welcome 2 new members home, Bill and Adam. Now we have over 50 members!

_______________________

3D printing workshop 2.0 went amazing; the workshop itself was more streamlined and we have 9 new people certified to run the Boulder Hackerspace 3D printers. Everybody got to leave with some cool “gear” no pun intended;) Ok maybe there is a pun here.

Here are some photos of the event:

2013-06-15 17.47.29

2013-06-15 17.48.22

2013-06-15 17.48.262013-06-15 18.03.16

Sign up for next week’s 3D printing class held on Saturday 6-22-13, the spots fill up quick so sign up today right HERE

I am holding an additional 3D printing workshop for a member’s business colleagues just prior; we’ll see how 2 3D printing workshops go in a single day=)

Hack on my friends!

 

Member Project of the Week: The Cyclophone

The Cyclophone in the Soundpuddle at Apogaea.

Ben and I had been talking about building a MIDI controller based off an Arduino for some time now. Then, about a month ago, with Apogaea just around the corner, we started thinking about making an instrument for the Soundpuddle, John English’s spectrum-analyzing dome. We thought it would be cool to build a circular keyboard, where each key would emit a tone which corresponds to a frequency bin on the Soundpuddle. Thus began development on the Cyclophone.

The Completed Cyclophone

The Completed Cyclophone

We did a lot of brainstorming that first week, which included building a couple of prototypes. The first prototype was just aimed at answering the basic questions: Can we reliably send note-on messages over the serial port, and without latency? Can wooden keys give a good tactile response? Will this even work? The result of these first experiments was a little creation that we affectionately call the “cuttlefish”.

The "cuttlefish" prototype

The “cuttlefish” prototype

The cuttlefish gave us a good first impression of how we were going to proceed, both on the hardware and software sides. One realization was that, as long as we were using our own custom software to synthesize the sounds (see my Pythagoras repo), there was no reason for us to bother with the MIDI protocol. We could just write small, byte-sized messages to the serial port, and then trigger callbacks in the software every time a byte is read. Another realization was that we needed to debounce the signal from the switches – otherwise, each key press would result in several erratically-timed notes being played. But most importantly, we realized that this was totally going to work maybe!

The next step was to move these concepts over to the circular table design. So we cut a circle (41″ in diameter) out of a piece of 1/2″ plywood, and made 24 cuts along radii from the outside. The length of the cuts was determined by experimenting with another single-key prototype to achieve a good action with the wood’s flexibility.

Testing out the flexibility of the first cuts in the top.

Testing out the flexibility of the first cuts in the top.

The next challenge was mounting the switches underneath the keys. We knew we were going to need a mechanism which allowed for adjustment of the switch height, because each key had a different flex according to its grain direction (the joys of working with wood). But the switches we had were very small and very simple (and very cheap) – they provided no easy way to mount them at all. So we ended up coming up with a system where the switch is clamped, facing down, between some blocks of wood on the underside of the keys. Beneath the switch, we thread a 1/4″ hex bolt through an angle bracket mounted on the spacer block. By turning the bolt, we could raise or lower the sensitivity of each key individually.

All 24 switch mechanisms, mounted on the underside.

All 24 switch mechanisms, mounted on the underside.

 

A close-up of a few of the switch mechanisms.

A close-up of a few of the switch mechanisms.

Once all the switches were on, we wired them into the Arduino and tested the action. We noticed that sometimes, depressing a key would warp the entire top in a way that pressed several other keys simultaneously. To make the whole structure more rigid, and also in anticipation of the “safety bumpers” we were going to want to put under the keys, we mounted another plywood disk, about 3 feet in diameter, on the bottom of the wooden spacer blocks, preventing their relative movement. This helped immensely in keeping the top from flexing like a big saddle every time a key was pressed.

We had also picked up some potentiometers and a rotary selector switch from JB Saunders, which we wanted to mount on the top to control some parameters of the programs we were running. So we mounted the rotary switch right in the middle, as a kind of mode selector, and then mounted the 3 pots symmetrically around that.

With knobs and bottom layer installed.

With knobs and bottom layer installed.

The neatly organized guts of the Cyclophone.

The neatly organized guts of the Cyclophone.

At this point, the Cyclophone was nearly complete – all that was left was to pretty it up. We thought about just painting it a solid color, but we realized that with such a large instrument, it’s actually difficult to keep track of the keys when they all look the same – a unique design would be much better. We had originally planned to have an artist friend paint the top, but with just a week left before Apogaea, and summer jobs keeping people busy, scheduling conflicts made that impossible. And so we were left – a physicist and a software engineer – with the task of coming up with an artistic design for the top. We ended up using the only graphic design tools we were comfortable with – polar equations – to come up with a sort of rosette design for the top.

Rosette made from 6 logarithmic spirals.

Rosette made from 6 logarithmic spirals.

Close-up of paint job.

Close-up of paint job.

The paint job took about 3 days, during which we applied 3 layers by hand. After that, we built a base for the thing, so that it sat about 12 inches high, good for playing while seated on the floor. Finally, Dan Julio donated an RGB LED strip and driver to illuminate the table from below.

Shown with LED strip illuminated.

Shown with LED strip illuminated.

On its base, painted and ready for Apogaea!

On its base, painted and ready for Apogaea!

At Apogaea, the Cyclophone took its place in the center of the Soundpuddle. We had it running off Ben’s laptop, with 5 modes to choose from, via the rotary selector:

  1. Chromatic sine waves (Soundpuddle mode)
  2. Tabla samples + koto, chimes, and guitar (all pentatonic)
  3. Half piano, half guitar (harmonic minor scale)
  4. FM synthesizer (major scale, parameters tunable by knobs)
  5. Drum circle
The Cyclophone in the Soundpuddle at Apogaea.

The Cyclophone in the Soundpuddle at Apogaea.

Here’s a video of the Cyclophone fulfilling its destiny at Apogaea:

We had a lot of fun working on this project, and I expect it won’t be the last USB controller we build (next step, velocity sensitivity!). It was also great being part of the Soundpuddle project – many thanks to John English and the entire Soundpuddle crew for making it all possible.

Nearly all of the code we used in this project is available in my Github repo. If you have specific questions about the construction of the Cyclophone, feel free to contact me (Chris Chronopoulos) or Ben Burdette.

Introducing the UConduit h-bot 3D printer / reprap!

 

What is the UConduit?

The UConduit 3D printer is an h-bot 3D printer, with a frame built from electrical conduit (steel conduit that you can find at the hardware store). It was designed by SSD member Lee Miller and is open source hardware via the Creative Commons Share-Alike license. It is hosted on github at https://github.com/iquizzle/uconduit. All printed parts are designed using OpenSCAD (which is an open source CAD environment) so that parts can be freely compiled and modified.

picture1

Why electrical conduit?

There are many options for framing. Most higher-end 3D printers these days are using aluminum t-slotted extrusion or specialty laser cut parts. While I think these options are achieving excellent results, I wanted to build a printer that also had a solid frame, but went back to the hardware store mentality of the earlier Mendel and Prusa printers. Conduit is extremely inexpensive ($3.50/5ft) and plenty stiff for a printer. It created some extra challenges in design work, but has an additional payoff.

The printer is held together using o-rings and compression flanges. Each end has two rubber o-rings. There is a “hard clamp” and a “soft clamp”. The hard clamped o-ring creates a pivot point and firmly holds the conduit in place. By adding a second “soft clamped” o-ring on each end, vibrations are very effectively damped. As a result, the printer is not only fast, but also super quiet! As a physicist, I’ve used this type of connection to create vacuum-tight seals on tube furnaces, which is where I first got the idea. Additionally, wiring can be neatly routed from the top to the bottom of the printer (using the conduit for its intended purpose!).

picture2

What is an h-bot?

Think etch-a-sketch! I’ve never deconstructed an etch-a-sketch, but I’d guess that it probably works in a similar way. Two motors are connected to a single belt, which is wrapped in an H shape. If you turn one motor and hold the other fixed, the print head moves at 45-degrees. Combinations of the two motors turning the same way or in opposite directions gives movements in the x and y directions. An advantage to this geometry is that all of the motors in the UConduit remain fixed. Because motors are the heaviest objects in a printer, the inertial forces are significantly reduced by keeping them stationary. I worked with SSD member Free Beachler to modify the popular open source 3D printer firmware “marlin” in order to accommodate the h-bot geometry. I’m very pleased with the results so far, but 3D printing is very competitive in the maker world right now, so you be the judge!

Here is a youtube video of it in action:

 

Learn How to 3D Print Workshop

ze printas

3D printing has started to become the talk of the town; so why not throw a workshop and teach others how to use it for their own personal projects? After all, we have 2 of them and have spawned about 18 of these self replicating machines with many other prototypes, trinkets, gadgets, and gizmos that members have made along the way.

ze printas

Saturday, June 1st, the first formal 3D printing workshop at our new location was held with an excellent turnout. A great group of 8 people with a broad spectrum of backgrounds showed up to add this useful skill under their belt and bounce ideas off each other; certainly a stimulating and entertaining environment.

tour

The main point of this workshop was to set you up for success; how to set up the printer correctly:

printers

tape

 

Calibrate it:

 

leveling

And then how to use the programs necessary to make your idea into a tangible object:

spaceinvaders

final product

 

 

Having access to this emerging technology is nothing short of…Awesome=) I’ll be hosting another workshop June 15th at 3pm; proceeds go towards helping SSD become a better place to Make, Hack, Learn, and Play! Sign up quick because there’s only a limited amount of spots left: http://www.meetup.com/Solid-State-Depot-The-Boulder-Hackerspace/events/121847242/

Looking forward to teaching you how to 3D print successfully and make some cool things=)

Hack on,

Bryant Hadley

 

 

 

Member Project of the Week!

This is not shameless self-promotion. This is what happens when no one sends me a project to post by Thursday — I post a project of my own! If you’ve been at the space over the last week or two, you’ve seen this taking shape:

100APPLE_IMG_0321

It’s a desk I’m making using reclaimed pine boards. They started life as my parents’ fence, looking like this:

A few passes through the auto planer, and voila! A finished desk. Well, almost finished. I’ve got a couple more rounds of sanding to do, then I’ll stain it and install. The legs in the picture above are just saw horses; it’ll be mounted on black steel pipe with flanges for feet.