sam roesch

Dash Design

2010-12-27T09:57:00.000-08:00

I'm working on the dash for the 2011 Baja car, in last years set up the steering wheel blocks the dash making it unreadable.

These are alternatives being explored, as well as potentially putting the dash in the steering wheel. The dash will be controlled by an arduino, receiving input from hall effect sensors in the drive train.

Laptop Woes

2010-12-11T19:17:00.000-08:00

Christmas is approaching fast, I need to find gifts for everyone, and I have been thinking: what should I get for my best friend? You see I feel bad because I haven't been treating him very well. I don't have a case for my laptop, he just gets shoved in my backpack everyday before I head to class, the machine shop, or on some trip. For a few months I've been thinking my poor MacBook could use some TLC (Tender Loving Care that is...) How about an upgrade to Snow Leopard? Yeh, he'd like that.
He's kinda scratched up, a bit dirty, and the stickers on the front are getting tattered. This is when I started having grand ideas of making him a new case from a big block of oak... or a carbon fiber case. Ridiclous. Ok, so how about giving it a matte finish like this iPhone on Lifehacker.

So, a new finish and a new OS, what more could a 3 year old MacBook want? I will work on it over christmas, after these exams are done.

What happened when I pulled out my laptop in the library last night? Nothing. Like actually nothing... the backlight is busted. Took an extended study break to reset PRAM, PMU etc.. still no joy. Figured out that mashing the contrast up/down buttons occasionally brings it back to life. Looking at it the wrong way sends the screen back to dark depths of having no backlight. I'm writing this post in between bouts of mashing the contrast buttons. I've decided that its just easier to keep on typing when the screen goes off. People in the library are giving me weird looks. "How can he see what he's typing?"

I perused iFixit today to see what I can fix, it might be the inverter (rated "extremely difficult" to replace) or it could be a thermal fuse on the logic board (more likely). Not sure what to do, as buying a new laptop is not an option, replacing the logic board is an equally poor $400 option.

It seems that SolidSmack (An awesome blog about SolidWorks) is having a laptop give away- what are the chances?! (Truth be told... that is the reason for me taking the time to blog about this!) It's an epic looking HP workstation laptop with enough specs to make my modeling and simulating work for Queen's Baja SAE a snap. Way better than trying to run SolidWorks on parallels, OR waiting for SolidWorks to take to the cloud!

Here's a look at what I'm working on:

Good luck to everyone that enters! (But my fingers are very much crossed!)

Birthdays!

2010-10-09T07:19:00.000-07:00

It's been 1 year since this site was born, and 21 since I was born... Happy Birthday website! It's very interesting looking at the most popular pages according to google analytics- the DTV shredder post pulled in tons of people... and a hundreds of people (well maybe tens of people) have asked me to make them headphone parts. Other popular items are the TB6560 stepper driver and the TDA2009A stereo amplifier.

Here's an idea of what I woke up to this morning:

T-Shirt Ideas

2010-09-26T17:58:00.000-07:00

Mid physics problem, I broke out some pencil crayons and doodled some T-Shirt designs.

These were inspired by Maker Faire NYC (wishing I was there), a play on the ubiquitous I <3 NY Tees...

Another boombox has been born!

2010-09-16T08:14:00.000-07:00

My friend Garner has completed his own boombox, just in time for school!

Very sexy Garner, good job!

Paris in B&W

2010-08-31T12:22:00.000-07:00

Photoset Photos taken with Nikon EM (35mm)

Zero Views

2010-08-26T10:55:00.000-07:00

http://zeroviews.biz/ lists great youtube videos that have zero views. This one I had to share. He has the same welding mask as me...

Arduino

2010-08-02T13:39:00.000-07:00

I finally ordered an arduino from adafruit, can't wait for it to arrive. Hopefully it will be here before this free arduino class starts: http://creativelive.com/courses/arduino/

Single sided TB6560

2010-07-15T07:27:00.000-07:00

I've uploaded eagle files to thingiverse for my single sided stepper driver based on the TB6560. It isn't tested yet, but people are eager to have it, so they can try it out. Tell me how it goes!

Battery Care

2010-06-20T09:30:00.000-07:00

Since killing another gel cell battery in my boombox I decided it was time to read into proper gel cell care. Here's a good link to get started.

It seems my big mistake was to use an automotive battery charger, as they do not regulate voltage particularily well. Gell cells like a high (around 14.4v) charge after a deep discharging, and then a lower voltage (around 13v) once charging current goes below a certain threshold. Smart chargers are great for this.

Canadian tire has one for around $35 that is fairly simple. A more complicated model that also desulphates the battery can also be purchased from there. A google of gel cell smart charger will probably turn up good results too.

Boombox Power Circuit

2010-06-20T08:17:00.000-07:00

A friend is building a boombox like mine, and wanted to know how the battery, charger and stereo were hooked up. Here is a quick circuit diagram explaining how I chose to wire the stereo.

The the switch serves two purposes in the circuit, the first is to disconnect the amp from the battery when the stereo is not in use. If this was not done, the Amp would slowly drain the battery, and potentially cause it harm by discharging the battery too far.
The second purpose is to allow the stereo to be hooked up to an external power supply like a large car battery, and have the internal battery disconnected.

Mention on shapeways blog!

2010-05-09T10:29:00.000-07:00

If printing something in 3D wasn't exciting enough, shapeways mentioned me in a recent blog post, and discussed the merits of printing replacement parts.
Coincidentally, I just finished work on a short presentation that introduces rapid prototyping, and uses this headphone part as an example. It mentions MakerBot, DremelFuge, BatchPCB, RepRap, Eagle and Thingiverse.
I hope to fix up the model in the next few days, and then people can go forth and print the model in any way they see fit, using shapeways the part could even be printed in metal. Rapid Prototyping

Headphone Bracket Printed!

2010-05-03T09:11:00.000-07:00

Printing your first 3D object is pretty magical, or at least I thought so.

There were a few issues with the model that I made, mostly due to incorrect measurements. I was impressed that the tiny tabs printed out in full detail. The next step is to correct the model, and also to strengthen the design with a larger fillet around the area that the bracket usually breaks. Soon I should be able to start making and mailing these MDR-V150 parts to people who asked for them.

You can see the flickr set here.

Update on headphone parts.

2010-04-28T08:56:00.000-07:00

I completely rebuilt the headphone bracket, with some improvements on the original. It also sits in a sensible plane now, so printing is more feasible.

All that is left is to try printing it.
You can print it too, the files are on thingiverse: http://www.thingiverse.com/thing:1777

Baja SAE in South Carolina

2010-04-25T21:14:00.000-07:00

This year's baja racer lining up for tech inspection.

This was before we were forced to weld two giant steel tubes to our frame because a "plane" in the rules is equivalent to a 2x4 during tech inspection. Live and learn!

DTV shredder

2010-04-18T07:53:00.000-07:00

This is a seriously awesome device!

Canadian engineer Ben Gulak is living the dream, he was recently recognized as one of Canada's top 20 under 20. He attends MIT, and somehow finds the time to start his own company that makes a segway-like motor bike called the UNO, and this DTV shredder. He was on Dragon's Den with his UNO invention, and has also been to the playboy mansion. He's an engineering superstar!

Single sided TB6560

2010-03-01T21:37:00.000-08:00

I've made some PCB designs for TB6560. The goal here was a single sided board, no jumpers. We'll see if it actually works.

Above is what BatchPCB sent me when I submitted them some gerbers. Not sure if I'll get Queen's to print me some, or if I'll use BatchPCB.

This is what I've got so far in eagle. Open source, but I don't really know where to host it, so just ask and I'll email it. I'm pretty excited that I managed to make it single sided, it should be great for hobbyists.

Golden Words Science Fair

2010-02-26T11:00:00.000-08:00

Golden Words Science Fair: Just Like Grade 5 should have been. Held in a bar and with cash prizes.

Queen's University's Engineer run comedy newspaper is holding its annual science fair in Clark Hall Pub, a chance to show of anything that you can create make or break! Grand prize is $400.

Not much time to hack together a project, but that's half the fun- current plans include stepper motors, beer, and the perfect pour.

Sony MDR-V150 Headphone Tear Down

2010-02-07T21:12:00.000-08:00

Many of my friends have either given me broken sets, or asked me to repair so many pairs of this headphone, that I have quite a collection of MDR-V150 parts.

These headphones are suprsingly delightful to take apart, as they are held together entirely by screws. Parts can easily be swapped and interchanged.

So... when I had to do a product analysis for a design course, the product was an obvious choice.

I also made a solid model of one part of the headphones.

As this part is the piece that most commonly breaks, I did some FEA just for fun...

The FEA is just a pretty picture, the magnitude of force is arbitrary, but what do you know? They break right where FEA suggests.

Did they name this fridge after my dog...?

2010-01-25T13:43:00.000-08:00

While shopping in Morocco, I came across a turkish brand with a rather funny name.

Maybe they are saying that they keep even their dirty parts clean, just like my dog. The real question you have to ask is: Would you pay 6899dh to get your arcelik? I'm not sure I would.

TBA6560 Driver Board

2010-01-17T16:34:00.000-08:00

Over the break I've been working on a driver board for the TBA6560, this is what I've got so far. It's open source, although I won't bother posting the files until it's a bit more substantial, and I've made the PCB layout.

It's a pretty simple circuit, the only tricky parts are figuring out values for certain parts. I got a lot of help form CNCzone, where there is an entire post on this chip. One of the important issues covered was that a low esr capacitor is needed across the 35v source. Setting the frequency is also a bit of a mystery.

What's new for 2010

2010-01-01T16:45:00.000-08:00

I've spent most of the christmas break planning out a CNC setup. My initial goal is to complete the electronics set up, and then worry about making a gantry later. CNCzone.com has lots of information on everything CNC, the open source stepper drivers are of particular interest to me.

I have reviewed dozens of chips from multiple suppliers, and I have also outlined the features that I think are good to have:

- Drive bipolar steppers
- microstepping, to at least 1/8 step
- Chopper style stepper control
- Handle around 24V and 1.5A rms/3A max or more
- Cheap!
- Easy to solder
- Easy to make a PCB for

Many drivers such as the EasyStepper that Sparkfun sells, and the drivers that run the MakerBot use SMT components, which are maybe a little to much for me to take on presently.

I looked through allegro's site, and STM, and some others- somewhere too tiny, some didn't microstep, some couldn't handle the power.

LumenLab switched their drivers from EasySteppers to a design based on TB8435 which looked way more... well, beefy and tough. Don't mess, you know? Its got easy to solder leads too. Too bad this chip is obsolete, and not made anymore.

Enter the TB6560! Its also made by toshiba like the LL one, but its still made, it looks tough, and there are some open source designs available on the web. I'm working on optimizing a design that suits me best, and then I'll put it up here FTW!

Ground Plane

2009-11-30T11:56:00.000-08:00

This is my first attempt at making a ground plane in eagle. Hopefully it will sort out some of the problems I was having with the first PCB I made. I have also thickened the trace that led to the right channel, as one speaker was much louder than the other.

Skateboard designs

2009-10-21T14:37:00.000-07:00

Here are some doodles of skateboard graphics that I came up with during thermo lecutre. I'm saving up to buy a new blank deck, and I'm going to try painting my own graphics on it. I should be able to make a stencil, as I think Queen's has a laser cutter somewhere that I could use. If not I will just cut it by hand.

Don't think I learnt much in this lecture...

Queen's Homecoming featuring the big orange boombox

2009-10-14T07:17:00.000-07:00

You can catch a glimpse of me and the boombox around 1:12. Let's party!

TDA2009A Chip Amp

2009-10-13T21:40:00.000-07:00

This is my first attempt at making a printed circuit board as well as making an amplifier. It came out much better than expected, and sounds great too!

The chuck barely holds the tiny bit.

My first PCB, thanks to cdx2000 for helping me design the PCB in eagle. cdx2000.blogspot.com/

Hooked up to power as well as a speaker. The resistors that are standing way off the board are only temporary as their value adjusts the gain, and they are much higher than recommended currently (Although sound quality is good). I used the boombox as a power supply.

Sometime in the future I plan to make another boombox with this chip amp (or multiples as you can bridge a few of these chips for more power) instead of using the power sucking car stereo.
For all of the arduino and POV type kits available, there does not seem to be much on the internet in terms of dead simple chip amp kits. I think that might be my endeavor.

Big Orange Boombox

2009-10-13T04:35:00.000-07:00

Here are some pictures of the boombox that I took in the spring, while procrastinating instead of painting.

The stereo was made from a construction sign. I used a CNC router to cut out the panels and make holes for the speakers and ports. This wouldn't be hard to make without a CNC, but my school had one so why not!

The top houses a car stereo. Above the stereo is a plate I made with external speaker output, USB charging, line in. Most of this is now redundant as I had to replace the car stereo ($100), and these days stereos come with USB, SD, and line in.
At the top right is the power connection for charging the stereo. It charges from a car battery charger.
The battery was a surplus 7Ah gel battery ($12) originally from princess auto, until it exploded. The new one is from canadian tire ($30)- they stock it as a replacement for one of their kiddy toys.

The speakers were salvaged from the side of the road. They are not very high end, but they were free. To get close to making the right size enclosure, I took measurements of the rotten speaker box that they came in, and then recreated that same volume when I designed the boombox.

Twenty!

2009-10-09T04:17:00.000-07:00

I figured now was as good of a time as any to start a blog, and given that it's on my 20th birthday, I'll have an easy time remembering the site's birthday. Maybe I should get married on my birthday too? One less thing to forget...