Friday, August 16, 2013

Boom Backpack

when i saw the boomcase on the internet i thought to myself "hey, i can do that!"

i started looking up what pieces i'd need in order to create some sort of suitcase boombox, i even had a spreadsheet. when it was all said and done, my spreadsheet had about $100 worth of components, and that didn't even include the suitcase. this is when i thought to myself, do i really want a $100+ portable boombox? what would i use it for? and that's when the idea was put on the shelf.

it wasn't until my brother told me that he saw one of the smaller boomcase listed in a store for $700. he said he wanted one for bay2breakers and for burning man, and that $700 was just a bit too much for him to spend. that's when i told him that i have wanted to make one for a while, but didn't have a dying need to own one.

he said he'd pay for parts, if build it! to me that was a win, for him it was a definite win. i used the dayton audio dta-2 amp, which was $20 and very small and light. it uses very little power and sounds great, the one drawback is that as you get close to max power, the sound quality gets horrible.
i was able to salvage the drivers from my old aiwa mini system. the system i got for xmas when i started highschool. somehow i had the speakers lying around, and i'm glad i did. they helped keep the cost down.
i did the electronics first, to make sure i had everything soldered and wired correctly.
then i cut some holes in a box and mounted the drivers to get an idea of how things would sound when the speakers were mounted. it worked great, i was about to tape the box shut and call it a day!
i made a few templates for the driver placement.
one driver installed.
and the second driver installed. sonically it's better to have these speakers side by side, but we're not making an audiophile listening setup here, this is portable audio.
i made a paper template that i used to make sure the tweeters would be mounted symmetrically.
this hard case backpack used a thin plastic shell over a thicker foam. while using the dremel to cut the tweeter holes i nicked the plastic, which you can see on the lip of the hole. next time i'll buy tweeters that have a baffle that covers the edge of the hole similar to how the larger drivers mount.
there was a decent amount of soldering for this project, but nothing that a beginner couldn't handle. this was my solder setup.
all four drivers mounted.
a peek inside...
this is a regular headphone jack, where the music goes into the backpack. this way you can hook up a smartphone, ipod, or anything else that uses the 3.5mm stereo headphone jack. the knob is on/off as well as volume.
for protection i mounted a few speaker grills over the woofers, per my brother's request.
this blue led lets you know when the amp is turned on
it runs on 8 aa batteries, but can also be plugged into the wall with an included ac adapter wall wort. on full charge batteries i've hit about 6hrs of playback at 1/2 volume. not shabby!
i ended up spending $122 in total and early on he said he wanted a backpack instead of a suitcase so his hands would be free. so this is what i created. i have to say it was a fun project, i just may do it again... i did pick these up from the antique fair

Wednesday, August 14, 2013

back to school

i've always felt my weakness was that i never learned a programming language. i remember hearing co-workers at my first job talk about how programming was something that can cheaply and easily be outsourced to places like india, and learning to program would corner you into being a lowly technical individual contributor. experience, making decisions, and managing were the 'real' jobs and skills to have. with those that's how you'd get the big bucks, not by being a code monkey.

 i took what they said at face value, not reading in between the lines of their advice. i was just out of college, i didn't know better. but now i see that these people telling me that coding is a waste of time, were rationalizing to me why they will never learn to code. most of them started their professional career when most desks didn't have computers, only pencil and paper. most of them used right click to copy and paste vs cntrl+c and cntrl+v. come to think of it, they didn't know any keyboard shortcuts.

but i heard the advice i wanted to hear. in college i took c++, and barely passed. i even had a weekly tutor session still i barely squeaked by. i thought that maybe programming is too tough for my simple brain to understand? and so these older co-workers who were also unable to program were telling me not to learn it, not to waste my time was just what i wanted to hear.

now i find myself in san francisco, during a huge tech boom. rents are up, prices are up, new companies are hiring like crazy, south bay companies are providing free wifi enabled charter busses to city residents who work down south. and almost all of these people are fluent in more than one programming language.

to think, the generation before me shed some bad advice. typical.

fast forward to right now. i find myself building excel formulas that use other formulas which take hours to compute. i think to myself, if excel was a programming language, i would have just written a pretty decent program. and that's when my fear lay down and i enrolled in a sql class.

sql - structured query language, is not so much about writing 'programs' as it is writing queries that pull and manipulate data from a database. usually you write a few queries in sql, and then write a program that knows when to use the sql queries to get the data that you want.

i took the class online during summer session, through the local community college. taking an online class was a brand new experience for me. each week i had two lectures to read, and two homework assignments to complete and upload. summer session is compressed, a normal semester only has one lecture per week and one homework per week. needless to say this was a very intense seven weeks. i stayed home on weekends, brought my laptop when i went to my parent's place, and even went back home after a few drinks to complete homework by the due date.

but i loved it. i was learning something that was directly applicable to my current job. half way through the course i was writing sql statements and pulling data faster and better than ever. of the possible 500 points for homework assignments, i received 478.

the final exam was the only portion of the class that we had to go to campus for. we sat in a dark underground classroom for 2 hours, and wrote our sql statements with pencil and paper. i never practiced coding with pencil and paper, though the teacher did advise this. there was one problem where i had to erase about 7 lines of code in order to insert a row that i had forgotten. there's no copy, paste, indent, or insert with pencil and paper. i bombed it, getting only 250 points out of the 400 possible. this resulted in me getting a b in the class.

don't get me wrong, i wanted to get an a. but i wanted to learn sql more.

it was frustrating when some of the lesser common aspects of sql were being taught. during some weeks the homework would ask us to write a query that pulls specific data, but to not use some of the built in features of sql. it's frustrating because no manager will ask me to pull some important data for our upcoming report but ask me not to use joins or like statements. it would be like asking a chef to not use knifes this week in the restaurant. but how else can you teach concepts that exist but aren't necessary? but maybe this i my way of rationalizing why i didn't get the a in the class. i've learned the lesson of rationalization and how to use it to make yourself feel good under the mask of advice that's for sure.

in all i walked out with a ton more than i walked in with. and today my next class starts. this class is 100% online, even the final. i'll be learning perl, and this is a 15 week course, not the condensed 7 week course that the sql class was.

Friday, April 5, 2013

my first cell phone

recently it was the cell phone's 40th birthday, as featured on gizmodo. this made me wonder back to my very first cell phone. i was working at a rotisserie chicken fast food joint that may have been associated with a grey haired country singer.

it was my senior year of highschool and sprint pcs was just coming out with their sprint pcs pioneer plan. The plan was dead simple. Pay $199 for the phone up front. $0.35 per minute, and first incoming minute is free.
so if you use the phone 1 minute for the month, your bill is $0.35! it was that simple. the phone was slim with a big LCD screen and an earpiece that would slide up and down to answer and end calls. the phone even had a timer that would beep at the 0:50 second mark so i was aware that another $0.35 was about to be spent on whatever i was talking about. usually if i was talking to a regular caller they'd know the drill and they'd hang up and hit redial so that we'd be able to have a 10 minute conversation on the go, for free! of course this only worked when they were ringing me from a landline.

sure it may sound normal for you to hear about a high schooler with a cell phone, but this was 1997!
princess diana died, gas was $1.22/gal, mike tyson bit evander holyfield's ear off, and the titanic was in theaters. at this point i owned a pager for a few years and i obviously needed much more powerful communication methods for my hectic lifestyle.

fast forward through my cell phone life and you'll see i went on to own a few different sprint phones, then jumped to nextel for a bit, and then on to t-mobile where the sidekick color and sidekick ii kept me more than happy. in fact, i owned a good number of wired's list of the 12 most influential phones including a $699 first generation apple iphone bought the day after its release.

happy birthday to my electronic leash, which i now use for navigation and games more than calls or texts. sometimes i wish i had that little beep at 0:50 seconds of every minute, but not to save costs -to save me from long phone calls!

Monday, March 11, 2013

record label saver

i have about 200 vinyl records that i started collecting in the early 2000's. Most of my collection is made up of primarily deep house music, with some various electronic tracks and an even smaller section of "everything else". I've been toying around with the idea of digitizing all of my vinyl records. i think it would be super cool to have the audio files of these hard to get songs in my pocket. the down side to this is that each record holds anywhere from one song to 45mins worth of music. recording them all would be a huge feat, imagine recording one record each business day for an entire year.

back when my friends and i would go digging for records, i'd buy most of these records for only 1 of the songs on the record. most records have 3 other tracks (2 songs per side seems to be the most popular format). so there is also the possibility that i'll discover some gems on sides of records that maybe received 10 seconds of my attention while i stood at a record store turntable auditioning stacks of records.

i recently input my collection of records on discogs (see my list here) to find that i have 246 records that are in the discogs database, and about 10 that aren't. The discogs database is real easy, each recording has a alphanumeric identifier making the lookup process real fast. doing this made me want to digitize even more.

but before i do an analog to digital conversion, i want to make sure that i can minimize as many snaps and pops that accompany old records as possible. i thought about buying different record washing mechanisms, but wasn't convinced i'd be happy spending $79.99 on a spin clean washer without trying my own diy project first.

i came across a label saver idea called groovmaster on an audiokarma thread. the design was simple and effective. after reading about different brush and solution ideas, i went to the hardware store and bought  a few items.

these two mini plungers looked perfect. and at $1.99 ea how could i go wrong?

record labels are 4" in diameter, this is just the size i needed.

i cut the handles off and drilled holes for the threads.

slipped the threaded bar through, with some washers and wing nuts for clamping power, and there you have it. two plungers that will end up squeezing my record during bath time.

i somehow have a copy of the original westside story broadway show, and it has been beaten to hell. i couldn't think of a better record suited for job of test drive the washing.

i washed a few records successfully, using a solution of 1/3 90% isopropyl alcohol, 2/3 water, and a drop of dish soap. after scrubbing along the grooves using my paint pad, i rinse with lukewarm water. some microfiber towels are used to dry the records and i'm good to go!

here we have an analog to digital recording in progress.

Wednesday, March 6, 2013

live edge trestle table part 7

sometimes woodworking requires a bit of clever thinking, especially when you are dealing with the cards that you've been dealt. this knot that wasn't very firmly attached to the rest of the tree was coming more and more loose. we tried to glue it, but there was no success.

so i drilled a big fat hole in it, and the hole went all the way through to the solid table slab.

here's the hole where the dowel and glue will be inserted.

here you can see it all. the dowel will be trimmed when we get closer to doing detail work on the edge.

link to part 8

live edge trestle table part 6

with the top glued up, and the location of where the legs are to be mounted nice and spot faced, it's time to get working on some legs. you've heard the phrase "measure twice cut once"? we measure 5-6 times, we chalk it up, we draw it out on paper a few times, then we line up the cut, and quickly review our chalk and paper, then we cut. and still there are times we goof it up.

these beautiful pieces of crotch walnut are also bookmatched. you can see the piece on the left has been planed and cleaned up, the piece on the right has not. but just imagine the saw going right through this piece, the cracks line up, and so do all other patterns.

here's a rough idea how the leg will look mated to the stretcher, of course this is upside down and the legs have to be trimmed yet.

so back to the router we go. the fences are set and clamped so that we cut exactly the width of our stretcher.

here's a router level view of the action.

we made the mortise 7/8 of an inch deep, plenty of contact area for strength.

this was a quick trial to see if everything was as we expected, since the stretcher is finished lumber the dimensions are similar enough to this piece that substitution was acceptable. the actual stretcher needs to be cut still, and will be more than twice this length.

it turns out our sled wasn't big enough, and the legs didn't quite fit. after a few minutes with the palm router we were set.

we measured the stretcher, and cut it to dimension, then set up the legs for another dry fit.

the stretcher fit perfectly into our mortise. with the base firmly in place, the only logical next step is to set the table top on and take tons of pics!!!

strike a pose with the table during the first time ever that it is assembled

link to part 7