Steve's Junk

Coolant mixture sensor (psuedo-refractometer)

smackaay — Mon, 15 Mar 2010 09:49:27 +0000

A bit ago I got the idea of trying to determine the mixture of coolant vs. water by detecting both light occlusion of the mixture and the wavelengths blocked / passed. This initial device is just a rough prototype that will assist me in determining a course of action in regards to overall design.
The idea behind the device is to have the sensor fitted on to any pipe attached to the machine where coolant goes through and give a live measurement of coolant mix and alert the operator if the mix gets too high or low. Also I’d like it to detect tramp oils that have been beaten in to the coolant.

Coolant meter board

The board itself is pretty simple, just a PIC16f690 hooked up to an rs232 driver and using three analog channels. I may in the future build a more sophisticated ADC board, but for now, this will do. The mcu is linked to the two rail to rail opamps, 7014D’s to be exact. they were needed to condition the signal from the LEDs.

Coolant meter test receptacle

The sensor area is basically a cup with a white LED as a light source for the sensor LEDs. The three LEDs are IR, Orange-red, and Green. The LED’s respond to wavelengths more energetic than the ones they emit, therefore, the selections I made. I did try a blue LED but the response wasn’t good at all. Hopefully it will provide useful data, hopefully.

Coolant meter terminal output

In order to make data easier to collect, I put rs232 communications on it. I can store and track data this way. Above is some of the terminal output. Notice that I’m taking 10000 samples… this has the effect of increasing, to a very limited degree, the resolution of the device. It is however fraught with error thus far…
Anyways, any data collected and the design of this is extremely preliminary. I’m not even sure it’s a valid or useful idea yet.
As an extra bonus, or punishment, here’s a video I made for this device.

Long time no post. Machining and trying to get back on my feet.

smackaay — Mon, 08 Feb 2010 07:57:19 +0000

Well, it has been some time since I posted, about a month and a half or so. There have a been a number of events that have occurred in that time that have both beneficial yet disappointing. I’m not really sure where things are going right now but I hope they get better.

Anyways, on to some things I’ve been working on.

Machining
While I am a decent machinist, it is a job that I vowed to myself I would never do again. Lo and behold, I am machining again in order to get some funds and to simply make it through the months in terms of rent and bills. Some of my previous stuff has left me bone dry in terms of money. Realistically, I should thank my lucky stars that I have a skill I can fall back on that pays well and is relatively easy, most others are not so lucky.

Luckily, the shop I’m working at is pretty decent, though I’m not the machinist I once was and my machining style doesn’t really match the pace and style of the jobber shop I’m working at. Hopefully I either get better soon or find something more along the lines of what I’ve become good at.

Stamping machine with the Haas mill
This is a little project that I came up with after thinking about dot-peen machines. Basically the idea is to take a Haas mill and allow full control of its machinery to turn it in to a makeshift dot-peen marking machine.
This feat is accomplished through the serial port with a pass-through interpreter box connected to a computer.

Here is how it is all achieved.

First Step: Computer -

This is where the points and fonts are generated and created. All of the end points are sent out from the computer at a lower baud rate than the mill uses. This allows for longer cable length on the RS-232. Of course I could use USB or RS-485 but RS-232 is more common an interface. A sample output might be:

MOVE X.455 Y1. (Basically a rapid move)
STMP X.461 Y1. (Stamp here)
STMP X.467 Y1. (Stamp here)
HOME (Go back home)

The communication is full duplex between the pass-through and computer so that the pass-through can request more data.

Second Step: Pass Through -

Despite its name, it does not actually pass data through. It interprets the data and controls the stamping head. It will interpret the data and send the machine the appropriate G-codes to perform the commands. The pass through will communicate with the machine at 115200bps whereas the computer <-> passthrough is about 9600bps. a sample output might look like this (based on the above text):

G00 X.455 Y1.;
G01 X.461 Y1. F200.; (move to stamp position)
DPRNT [S]; (Is at position, passthrough will stamp)
G01 X.467 Y1. F200.; (move to stamp position)
DPRNT [S]; (Is at position, passthrough will stamp)
G28 G91 Z0;
G28 G91 Y0;

Third Step: Stamping head -

Not really a step so much as device to peen the surface of the part. Here is a picture of an earlier design I made for a stamping head.

I don’t know if I’ll ever do this one. Macros need to be enabled in order for this to work so a lot of machines won’t be able to take advantage of it. Also, my time is limited.

Programming a CAM system

Since the shop I’m at has no CAM system for the guys on the floor and I don’t want to use a cracked copy of say, Gibbs or MasterCAM. I’m writing my own. The going is slow but I am slowly developing a little 2.5D cam system. The math function are working and the object creation is starting to come on line. Now for an interface. I am thinking of migrating over the VB.NET for this program since it does have a lot of nice object handling functions and it is a little easier than creating a user interface from scratch.

Anyways, That’s what I’ve been up to for the last while. Hopefully I get a car soon so that I don’t have to walk in this anymore.

This was taken on my walk home the other day.

A crummy little servo tester and other minutia

smackaay — Mon, 14 Dec 2009 23:58:07 +0000

The little servo tester
Well, I needed a way to test all of these servos I got from EBay and I decided to spend a little time making a quick and dirty little board for doing that. It uses a PIC12F683 and has a linear pot attached to it. Simple.

Crummy servo tester

Viscometer Board and stuff
I’ve been working on the software for the viscometer. Every function appears to work, at least based on the rudimentary prototype I have currently running. I am working on a scripting system for this device. I could make it just a basic viscometer but, as anyone that knows me, I simply can’t do. Here’s a pic of the working board.

The prototype viscometer board

An EEPROM file system
After thinking about how to store files appropriately and trying to have a file system that can work easily with 1024B of space, I started coming up with ways of defining a reasonable file system. Here it is.

First 2 bytes are settings, things like block size, filename size and special behaviors like for EEPROMS that can only be written to with blocks.also defined is the address size 8b, 16b or 32b
Each file in the FAT consists of a name of either 2,4 or 8 bytes. this is determined by the setting.
Following the name is one byte detailing the flags such as read-only, archive, and whether it’s open or not.
After the filename and attribute byte, are the addresses. These addresses can be 8, 16 or 32 bits, however, an 8 byte address can address something larger, say 2k rather than 256B if you set the block size appropriately. This of course lowers the efficiency of storage space but allows for some growth in the file. The file can have any number of addresses in order to remove time wasted moving stuff around.

Anyways, that’s what I’ve been working on as of late. Fun!

Viscometer board proceeding, some RS232 fun.

smackaay — Tue, 01 Dec 2009 18:17:59 +0000

Well, things have been proceeding apace, and I’m feeling pretty confident that I’ll have both versions done fairly soon. For debugging the device I’ve decided to create a kind of terminal, this allows one to directly access commands and see log information from a terminal program. This is handy for seeing data over time and for various other uses.

Here are some pictures…

Prototype viscometer board out futher

Prototype viscometer board

The early output of the sample terminal. I have created a kind of console, I will implement commands as they are created.

I think this is going to turn out well.

One last kick at the can, Viscometer Style!

smackaay — Sun, 29 Nov 2009 00:24:12 +0000

Well, since funding for the viscometer has fallen through for various, understandable reasons, I have decided to take one last kick at the can before I shift my focus on to other ventures. The last kick at the can? Two similar viscometer heads, two very different purposes.

This is the rough mockup of the new head, it is the same for both designs

The hand-held stormer

  This device is designed to work in the field and provide readings in KU, Grams and perhaps Centipoise. The device itself doesn’t feature any communications of any kind. Also, there is no LCD display, instead a 7 Segment x 4 LED display is used since it’s a bit cheaper and more visible in various lighting conditions. Also, since it will be use tables of values rather than calculating it on the fly, I can use some slimmer hardware such as the PIC18F2620 Microcontroller or an ATMEGA8.

  Also of note is the fact that everything is fairly cheap to build, these low-cost viscometers could be used in paint shops in any size container. I am building one to go to Cold Lake where they’re going to try one out since they’ve been having trouble getting decent consistency using only a mixing stick to test viscosity.

  Here’s a rough mockup of what it will look like. Of course none of the boards or covers are shown, also the display isn’t visible, I haven’t decided the best location for it yet. I may actually put it inside of a separate enclosure to make the unit lighter since it requires 12 volts.

Mockup of the handheld viscometer

  This is probably the most marketable device thus far.

The Super-Visc

  Over the last 9 months or so I have developed a number of interesting methods for determining error and correcting for it, I have also develop methods for calibration and symbolic parsing. Since I would hate to come away empty handed and waste all the of knowledge accumulated over the course of 2+ years, this is the coup de grace of rotational viscometers.

  To my knowledge, most other rotational viscometers use a beryllium copper torsion spring to provide a fixed, known spring rate, or torque on the sensing shaft. The cheap ones like the stormer viscometer base it on time and run a fixed speed AC synchronous motor, whereas the more expensive ones use a variable drive and encoders on the top and bottom to determine the difference from top to bottom. My viscometer uses the cheaper method of determining difference and RPM by using the timing via ether opto-interrupters or hall effect sensors. By using a a very high sampling rate, I can get very precise measurements of the rotation, though some differences may occur during rotation. Accuracy is achieved through error correction in the form of running averages, temperature and friction compensation and angular displacement compensation. While this is places a heavy burden on the software side of things, it is extremely effective.

  This viscometer works on three key concepts: Variables, Equations and Test Programs.

Variables – These are variables that are calculated dynamically before any other calculations have taken place. These include ambient temperature, fluid temperature, angular displacement, spring length, time from test start, time from last sample and other mathematical constants such as PI and E.
Equations – These are the equations that determine the units. You may (and for basic units, must) include variables in order to calibrate the device. These equations are completely configurable by the user and includes every standard mathematical function such as Cos(), Sin(), Cosh(), Powers, Square Roots and many others, perhaps even logical equivalents say to multiply by 1 or 0, could be useful. While developing this I had a choice, either computationally expensive or memory intensive, I chose memory intensive symbolic storage in order to improve performance. This also allows one to develop any unit with any paddle one wishes!
Test Patterns – These are the patterns that develop the test. For example, let’s say you want to test for KU. You place the appropriate spindle in the machine and select the KU test run. KU test runs would appear as follows (200 RPM Fixed, Equation KUPU, Out->FLTP, Out->KU) or for Centipoise vs RPM (50-220 RPM variable, Equation CNTP, Out->CNTP, Out->RPM, Out->FLTP). These are a boon for the experimentor.

One key disadvantage of this device is the initial difficulty of calibration. However, if done en masse in the factory, it wouldn’t be an issue. One of the major advantages of this device is for the experimenter. You could put a hotdog on a stick, put it in a fluid, create a relationship via an equation and call it whatever you want. The device is very configurable and would probably be well suited to materials engineers and chemists who need either standard or non standard tests with a large amount of automation in terms of data collection.

Here’s a mockup of the finished laboratory device.

Potential mockup of finished device

The device will feature an RS485/232 output along with perhaps a touch screen or simply a keypad and 20×4 LCD display. The processor will either be a DSPIC33F or PIC32, I may stray towards Atmel since they have great throughput. My current prototype board however has a PIC18F4680, it’s enough to test on but its limits on RAM are starting to bother me.

Well, this was a long post… Whew

As always, anyone who has any questions can leave a comment or E-mail me.

Stormer Viscometer Grams to Oz-Inch Conversion

smackaay — Wed, 11 Nov 2009 02:24:38 +0000

Trying to make sense of the standard stormer viscometer and methods that could be used to calibrate a device, I’ve been looking at the original stormer viscometer in order to get an idea of what ‘grams’ actually means in the case of the stormer viscometer. Here are some facts.

The weight in grams is held on a pulley and pulls on a rotating pulley that is 1.125″ in diameter. That pulley rotates some gears or belts at a ratio of 11:1 (1 rotation of the pulley = 11 rotations of the spindle). Taking the torque applied on the main pulley and dividing it by 11 results in the actual torque to the spindle.

Simply because I use it in these cases, here is the conversion ratio for grams hung on the instrument to oz-inches. Also, one should keep in mind that there is some loss of torque due to mechanical limitations.

oz-inches == .00367056 * grams

therefore, using this formula, a KU meter ranging from 32 grams to 1099 grams ranges from .1174 oz-in to 4.0339 oz-in.

yay! Hopefully someone finds this useful as well.

Grams to Krebs conversion formulae

smackaay — Tue, 10 Nov 2009 21:02:39 +0000

After many a day scratching my head as to why I can’t get my viscometer to calibrate correctly, even assuming logarithmic and quadratic relationships, I find out why I have been having so many problems.

Krebs units are in not very linear!

I have found an old chart with lots of grams to krebs conversions on it and after painstakingly transcribing them, I have come up with the following graph.

Grams to Krebs (grams on horizontal axis, krebs vertical)

As you can see, there are a number of points of inflection along this graph. Here are some images of the various best fit scenarios regarding this set of points. These points encompass the KU values 40.1 to 141, just for reference.

Linear (0.0813637)*x+(64.5289)

Quadratic (-0.0000813007)*x^2+(0.173302)*x+(46.274)

Cubic (1.01193e-7)*x^3+(-0.000252971)*x^2+(0.253045)*x+(37.7895)

Quartic (-2.3958e-10)*x^4+(6.42986e-7)*x^3+(-0.000653817)*x^2+(0.359922)*x+(30.3868)

Quintic (1.93677e-13)*x^5+(-7.87171e-10)*x^4+(1.20087e-6)*x^3+(-0.0008998)*x^2+(0.403747)*x+(28.1763)

As you can see, a quartic relationship is quite passable though I still added a quintic relationship. It may be possible to make a simpler equation based on these values but I thought it prudent to stick to what I know.

You can see the dataset here. GramsvsKrebs.txt

Be warned, I may have made mistakes or the chart may have been wrong, Do your own research if you want to be certain of your results. Hopefully this is of help to somebody.

Working on new viscometer head

smackaay — Tue, 06 Oct 2009 18:40:50 +0000

Well, I’ve been designing some new stuff since having a little wind of inspiration. This head weighs in at about 700g and provisions have been made to allow an attachment to a handle and therefore a hand-held version could be made. Here are some images.

Line Drawing

Fully Assembled visc head

Viscometer head opened

Viscometer head from the back

I’m going to use these design concepts on the next in-process version. I’m going to design the external case for the electrical portion and for possible battery storage. Since the motor only draws 100ma at 24v or 200ma with a 12v motor, a hand held version is definitely possible. This version will use a PIC16F767 for control and using a smaller LCD display to display info.
Now, on to developing some other devices. I’ve wasted far too much time in the last many months, time to get busy.

Quick post, a couple of drawings.

smackaay — Fri, 02 Oct 2009 06:26:22 +0000

The chill is in the air, October is here. I’ve been pretty busy with the viscometer and some other things, however I drew a couple of objects just for future reference. I figured somebody might need the dimensions of either a stormer viscometer paddle (as measured from a real one) or a QY-2004A white LCD display (blue backlit)

Anyways, here are the links to the drawings in PDF format.

stormer paddle drawing PDF
qy-2004a drawing in PDF

I’m going to draw up some of the rarer parts I have, I may need them later and somebody else might be able to make use of them. Keep in mind, these are rough drawings taken from measured features. Don’t assume that the measurements are the same for all units except perhaps the stormer paddle.

Getting closer to final completion

smackaay — Wed, 23 Sep 2009 02:11:19 +0000

A long road behind and still some ahead, here are some pic of the viscometer in its state of completion.

stormer viscometer with cover looking in

viscometer from the back

viscometer standing up

viscometer laying down

stormer viscometer with cover

Now to implement the ModBUS protocol and finish up this project.

Krebs to Poise Formula

smackaay — Sat, 05 Sep 2009 02:50:17 +0000

Looking for a decent formula on the net for a Krebs to Poise conversion I’m left empty handed. I found a chart that had listed direct numerical conversions.

Here’s the Best Fit value in the Quadratic form ax^2+bx+c=y

y=0.00419037x^2+(-0.306745)x+6.40025
y=poise
x=krebs

It may be somewhat rough, but since KU is a unitless value…

In-Process Stormer Viscometer – Damn near complete

smackaay — Tue, 25 Aug 2009 01:27:49 +0000

The viscometer is nearing full completion! YAY! To mark this occasion to mark the end of a long two years, I am placing a small gallery of the almost finished product. The only thing missing is the outside cover which consists of a 4″ od aluminum tube. Also, the springs I’ve ordered have also not arrived as yet, however, for now, the elastics will suffice. Here are some of the features and facts:

Can be used in-lab or in-process
Selectable RPM with a tight tolerance on RPM +/-0.5RPM
User calibration routines. This allows the end user to calibrate with 3 fluids of known viscosity
16 key keypad, used for calibration and settings, also for running special tests
Can be used as a laboratory gel-timer
Can be used for custom tests besides stormer viscometry
Low power consumption <100ma or <2.4W
RS-485 Serial output
Control electronics have complete galvanic isolation
24VDC supply required
repeatability (requires further testing) +/- 1.5%
Modbus protocol (not yet implemented)

Yay! They work!

smackaay — Fri, 21 Aug 2009 22:23:07 +0000

Well, I got the power board and control boards done. They both work flawlessly. YAY!

Power and Control and LCD

The peripherals seem to work too.

Spring Stormer Viscometer, proceeding, the board works.

smackaay — Sat, 15 Aug 2009 23:49:18 +0000

Well, I recently recieved my boards back from ap circuits in Calgary and I’m pleased with the result. I kind of fucked up by ordering 4 of the same board and not 2 of the control board and 2 power boards. Oh well! I can use the current boards for the new ones. Anyways, here are some images of the board.

The two boards together, unpopulated and populated

The board, populate with SMD's

An experiment in heat transfer

smackaay — Sun, 09 Aug 2009 22:37:40 +0000

  After being apprised of an issue with heat transfer through PCB traces, being the stubborn idiot I am, I had to try and solve the problem. The issue is with a particular PCB that has a cutout section with a thermistor placed in a partially isolated section within the enclosure, unfortunately the traces themselves are serving as a heat transfer conduit especially so since copper is a particularly good conductor of heat.

  After thinking about it for a while I came up with a couple of ideas like calibrating the calculated output to accommodate for the temperature discrepancy, however that probably wouldn’t work without a second thermistor closer to the heat source, accounting for the difference. Another idea I had was to use an infrared thermopile but they’re kind of large and expensive and would require a heat channel mounted above it to prevent measuring the temperature of the case.

  After thinking for a while about it, the simplest answer I could come up with would be a heatsink to mitigate the heat transferred to the thermistor. While it is theoretically impossible to totally remove all heat difference, I believe that a large portion of the heat transfer can be eliminated. So I wanted to see if heatsinks actually help equalize heat much at all so I devised a bit of a rough experiment.

The Experiment

  I decided the quickest way to test this would be with materials I already had. I have a selection of thermistors so I used a glass axial thermistor.

This is the thermistor board used in the experiment. the thermal leads aren't attached.

The circuit used for the test. Beautifully illustrated

The thermistor used is a glass 10kOhm NTC Thermistor in series with a 1k resistor in order to detect current/divide voltage. With the setup above, the voltage detected from GND to the divider is 438mv. the temperature in my basement is pretty steady since the furnace isn’t running. So now I attach the leads.

This is the board with the two 22AWG leads attached.

I also performed the test with the leads closer to the thermistor.

I used Teflon coated wire to prevent conduction between the two sides and used my soldering iron as a heat source since it’s temperature controlled. I let the heat soak up through the lines for 10 minutes to ensure that the heat stabilizes at the thermistor. I also performed a test with the soldering iron closer to the sensor.

Finally, I decided to place a heatsink on the line. I was going to solder aluminum shims to the leads in order to provide for heat sink. That turned out to be difficult at best, so I used coiled up copper wire and soldered it to the leads. I performed the same two tests with the position of the soldering iron. Anyways, here are the results of the test.

Test Type	Voltage Recorded
No leads, ambient	438mV
With Leads, ambient	438mV
Pressing thumb on thermistor ~33.1c	554mV
Heat with long leads, No sink	496mV
Heat with short leads, No sink	625mV
Heat w/ long leads, w/ sink	476mV
Heat w/ short leads, w/ sink	544mV

It should be said that this test is far from perfect and doesn’t prove anything quantitatively with any real degree of accuracy, however I wanted to see how effective even a rudimentary heat sink would be in a situation like this. It should be noted that while thermistors are inherently non-linear, we have voltage drops of 43% and 34% with the short and long leads respectively. I simply thought it was an interesting experiment. I have a few ideas on how to sink the heat or account for it but I think the heatsink is the easiest plan.

Here’s a beautifully rendered image of the idea to reduce thermal linkage between the PCB and the thermistor .

The thermal isolation idea. By placing a heatsink on the exposed traces one could mitigate the heat transferred to the thermistor.

If there were a heatsink over the exposed traces and the traces made as long as possible, it should be possible to bring the traces fairly close to ambient. Like the experiment showed, even a rough heatsink was able to reduce the heat going to the thermistor by a substantial degree.

Feel free to comment.

FDM Part Prototyping

smackaay — Mon, 03 Aug 2009 18:52:46 +0000

This post is simply to show how neat the FDM process is. FDM stands for Fused Deposition Modeling and is a neat tool for prototyping plastic parts. I was able to see the results of FDM after a customer had one of my models done with the process, he was nice enough to let me take some pics of it . Frankly I think this kind of prototyping opens up a wide variety of interesting possibilities in terms of being able to develop plastic enclosures and various other mechanical projects.

Here are some images:

The two peices in FDM, this is a deposited ABS IIRC.

I altered the levels to show how the process fills in non critical areas. Of course it would depend on the machine performing the action.

Corner Detail FDM

This is a very interesting process, hopefully I can make use of it in the future.

Here’s the wikipedia article http://en.wikipedia.org/wiki/Fused_deposition_modeling

Programming, Drafting, Designing and whatever else…

smackaay — Sat, 25 Jul 2009 22:38:56 +0000

Well, it’s been a busy few weeks since I left the business training program. Thankfully I have some work lined up and things may go well for the short-term. For the last while I was working on the design for a plastic enclosure for a customer. Everything went quite well and the customer is an absolute joy to work for/with. Based on a board and taking cues from other ideas, I drafted a simple enclosure for a device. Here are some pictures of the enclosure.

Worked out well…

Also, I am now continuing my foray into the automation stormer viscometer as well as my auditory camera level. Things should go quite well if I bust my ass…

A quick post about my website.

smackaay — Sun, 05 Jul 2009 22:54:26 +0000

I’ve finally had some time to put together my website for my business. 8mtech.com is online and has most of the pages complete. I’ve decided to keep the layout very simple and I’ll eventually flesh out the theme a little better.

As an aside, my business cards came in, they were very nice. print100 based out of Hong Kong did a good job. $30 for 300 cards with corner cutting, matte finish and double-side colour. Very nice!

Anyways, if anyone wants a freelance inventor or a draft monkey, give me a call!

Time’s a passin’ – DIY Arms, Music, and invention

smackaay — Thu, 25 Jun 2009 20:26:11 +0000

Well, the past few weeks have been eventful and interesting. I’ve been busy and school is almost over. I’ve had a few things on the go and I’ve come up with some interesting ideas and implementations. Sorry for the lack of images in this post but I’ve been lazy taking them.

The DIY Measuring arm
This idea came from the need to build a measuring arm at a very low cost. I simply used some wood and some regular linear potentiometers.

The cheap and quick measuring arm, this image doesn't show the wiring or the board behind it.

This so far works reasonably, though it does have some linearity issues. I will need to bring this unit in to the shop to measure the joints and determine the exact positions in order to calculate the position.
Rock band device
I was inspired by a fellow classmate to build a device for teaching children how to play the drums and other instruments. I can’t get into any hot and heavy details, however it was a success for two drums to be made. The sensors worked and transmission of the data was reliable and the software worked. It was a lot of fun to build and we may work further on the idea with better design specifications.
Auditory Camera level
My idea for an auditory camera level is working to an extent but I’m having difficulty filtering out the vibrations from arm shake and the like.

Anyways, things are going well but it’s a lot of birds in the bush and none in the hand. I’m just writing to keep a log of what’s happening

A brief post, school and business

smackaay — Wed, 10 Jun 2009 14:38:16 +0000

Well, I’ve been at Microbusiness Training center for 5 weeks now and I’ve been working as well. Soon, Eight-M Technical Services will be operational and i’ll be working for myself.
I’ve set up a new domain with my Dreamhost account. The site’s URL is http://8mtech.com. As of posting this, the site isn’t ready, but it will be soon.
The viscometer is being tested by Endura right now and here’s what it looks like, it’s a youtube video, be warned.

also, I figure it’d be neat to post the logo for Eight-M technical.

my logo for 8m

Some people who have known me since Junior High would know this symbol. While it was something I used as a kid, I started using the name Eight-M Designs in order to order stuff because companies wouldn’t send swag out to an individual.

Chaos game, a little program.

smackaay — Fri, 22 May 2009 04:09:09 +0000

Was bored for a little while today so I made a quick program in Freebasic to produce a Sierpinski Triangle and a some sort of pentagonal fractal. This little program uses the chaos game method to produce it.

seirpinski triangle

seirpinski at 5

I think the result is kind of interesting, I’ll post the crummy little program.
choppy.bas
Nothing special with this, just the result of boredom. You could change the radius and the ox and oy variables to look deeper into the triangle/pentagon.

Rotary Viscometer almost finished

smackaay — Tue, 19 May 2009 01:15:45 +0000

Well, it’s been a long road but I’m almost at the finish line in terms of the majority of development. All of the parts are mostly made and I’ll begin programming very soon, most of which has been done already or figured out in advance.
Firstly, I started with the board. I had to build it from scratch because I’m not certain of they’ll want more features or different ones, also I simply don’t have the funds to get the printed boards made, those will fit in the top of the unit below the LCD and reflection switch.

viscometer test board with lcd display

Viscometer, assembled on base

So, after this I spent the entire weekend building the parts required to make the rest of the unit. I opened up a few of the tolerances and had to make some changes simply to allow for better fitting afterward. The unit would have been impossible to assemble otherwise

Viscometer with sensor in hand

I have to say, I’m satisfied with the results thus far. The bearing holding the sensor together could be a bit better though. This week I’m going to have to program the unit and hopefully this long saga will be over. Well, at least when I make the 15 units it will be.

3 point quadratic regression formula

smackaay — Wed, 29 Apr 2009 22:01:05 +0000

While developing the in-process stormer viscometer, one of my goals is to allow the end user to calibrate the device with 3 fluids of known viscosity. With a bit of help from mathematica, I’ve found the formula and for whoever wants it, it’s posted, also for my own future edification. This formula is meant to convert 3 data points of the form {X1,Y1},{X2,Y2},{X3,Y3} into a form of ax^2+bx+c=y. This is probably the fastest way to do this kind of operation on a microcontroller. Here’s an image of the formula

Reverse Quadratic from data

also, here’s a dirty FreeBasic program using it. regress-3point.bas

Also, for fun I decided to do a cubic version. This is in the form of 4 data points {X1,Y1},{X2,Y2},… converting to ax^3+bx^2+cx+d=y

Cubic equation inverse

You gotta love Mathematica!!!

Viscometer Project, coming along…

smackaay — Tue, 21 Apr 2009 07:50:05 +0000

I thought I would have nothing to post but I do I guess. I’ve felt the need to really expedite this project now that I am starting a business. I have done a few of the mechanical things associated with it after a major redesign. Today I have completed the design of the board and despite it’s sloppiness, I’m happy it’s done. Now to get it made.

Viscometer Board 3D View

Viscometer Board traces

Like I state in the description, I used the autorouter on this image, I may revise many of the traces so that ripple can be eliminated from IC’s by bringing the caps closer electrically to Gnd and Vcc. This week I hope to finish the machining side of the device, I’ll have to wait for bolts from Fastenal to arrive but it’ll be worth the wait. Here are some shots of the parts so far, note that the main block is made of phenolic, I love this material since it looks kind of like wood but is reasonably machinable.

Machining the block

Phenolic Block Finished

Coming along, main block and holders finished

Just for the record, here is the list of, well electrical features:

16 key Keypad for data entry, mostly for calibration.
16×2 LCD display for seeing alarms and viscometer output.
24V motor, PWM driven with TIP102
Light interrupted sensors for top and bottom
provisions for temperature sensing
RS-485 Out
Provision for an external RS-232 board, if needed
TVS’ed to the hilt, hopefully this will prevent funny stuff from happening.

Anyways, let’s hope she all works out in the end.

Still goin’ at ‘er, now attending the self employment program

smackaay — Tue, 21 Apr 2009 04:31:35 +0000

Well, no new project pictures or anything. Summer is almost here and I’m pretty happy about that. I’m going to start at a training course for 8 weeks starting May 11.
The program itself is funded through the Canadian Government or Employment Insurance. This program is geared for people who wish to start their own business but lack the experience starting one. This program also has a 4 month post-class coaching period. From what I understand, they assist with the minutia of business and get you hooked up with financing. This program also allows one to keep collecting EI through the 6 months of the training, but not afterwards.
My idea in this case in terms of starting a business is a nebulous one at best at the moment, however, I think that by lending my skills as a machinist and programmer and technical dude, hopefully I can eke out a living or perhaps even a prosperous business in these difficult economic times.
I think that this program will help give me an introduction to the business skills I lack in abundance. Anyways, hopefully tomorrow will be a sunny day, I want to do my full report on minolta md lenses.