Room 203 Technology

I Just Noticed...

2012-01-17T17:55:00.000-08:00

My roughly 6 year old Macbook Pro battery is charging at the same rate as my mid-2011 iPhone 4 battery. I realize that the screenshots don't prove what I'm observing, I just thought it was an interesting coincidence. I checked twice an hour apart and the percentage was the same both times. Since that time the phone has leapt ahead, but that was expected.

New Equipment

2011-10-04T18:39:00.000-07:00

I have some new equipment to play with now! From bottom to top: Isolation transformer, Oscillator, Fluke DMMx2, Waveform Synthesizer and HP voltmeter. I'm planning on getting an oscilloscope in the near future and a rack mount PC chassis so I can use GPIB ports, USB etc. for data collection.

Custom iPod Dock

2011-10-03T15:46:00.000-07:00

A couple months ago I decided I wanted an iPod dock for mounting on the wall. The plan was to use it as a wall mounted (and portable) iTunes remote. I couldn't find anything on the market that had the 'aesthetic' I was looking for and so I set to work building one. Behind the screen is a sheet of polycarbonate that I sandblasted; it serves as a diffuser for red LED lights. When it is set up the screen behind the iPod glows red and lights the wall around it in a red glow. My goal was to give it an industrial look and I think it turned out pretty well.

Java Calculator

2011-02-15T01:29:00.000-08:00

Recently I wrote a program in Java that provides basic calculator functionality with a few more advanced features such as a recent history pane, square roots, reciprocal, powers and percentages. It does not have the problems associated with floating-point math because I have used the BigDecimal class. The backspace feature, decimals and negatives work properly. Problems I have not dealt with are screen overflow, and the ability to enter numbers and operators with the numpad. Currently number entry is strictly done by clicking the buttons. Program is available hosted on Windows Live SkyDrive. Please do not distribute, thank you.

New Case

2010-02-12T22:12:00.000-08:00

This picture shows my HAF 932 case on my desk. You can also see my other desktop and laptop. The HTPC is in another room. Above the main computer is a lamp I built over the most recent Christmas break with some glass blocks and a lamp. The eventual goal is to light them individually with LEDs a different color for each block.

Budget Case Mod

2009-12-06T01:18:00.000-08:00

The economy has made it tough for people to justify modding their computer cases. If you're going to spend money, it's easier to do it if it's actually going to be improving performance. With this low cost solution you will never have a wife/girlfriend/loan department/collection agency nagging you about spending money on unnecessary upgrades. The materials that you will need are black construction paper, a white plastic bag, tape, pencil, ruler, CD, penny, exacto knife, some LEDs and a computer case with three empty 5.5" bays. I didn't get pictures of the process so you'll have to have to bear with a verbal description.

Step 1. Cut the construction paper to the size of the empty drive bays without the covers on them.
Step 2. Center the CD on the paper and trace the outside and inside circumfrence.
Step 3. Center the penny and trace it. It should make a circle slightly larger than the inside of the CD.
Step 4. Draw a line horizontally across the center of the circle, then two more lines that should be about 60° from eachother.
Step 5. Using an exacto knife cut along the lines that you just made and punch out the parts you don't want.
Step 6. Cut the white plastic bag and tape it over the back of the the cut out.

If you want to backlight the logo, figure out some math and put a proper amount of LEDs and resistors and hook it up to your power supply. Make sure you insulate non-ground wires since if they touch the case they short and will shut off your computer. Please remember that you are building a mod out of tape, construction paper and a plastic bag. It looks good from a distance, just don't let anyone get too close if they are the picky type. Here are the pictures that I took of it, click on them to see them bigger.
-Quentin Swager
(guest writer)

M8 Progress

2009-03-12T11:20:00.000-07:00

I haven't worked on the coilgun for so long I felt almost guilty. I decided to get a little done, so I cut the new barrel to length, and wound a small coil for it. I haven't tested it yet, and the barrel isn't slotted so there will be eddy current losses or worse.

Finished X Box 360 Monster Energy Case Mod

2009-01-25T04:54:00.001-08:00

We also put a window into the hard drive.

Celebrating a working modded 360 by drinking Monster!

Photos: Quentin Swager Photography

More progress on the x box 360 case mod

2009-01-25T04:44:00.001-08:00

Soldering on the mobo made me very nervous. We did get the rrod when we got it all together but that turned out to be a simple problem. As simple as it was, we still spent at least an hour freaking out looking for the problem.

The pics, again, were taken by Quentin Swager

Xbox 360 Case Mod

2009-01-21T16:56:00.000-08:00

As the title suggests, this post is not coilgun related. This is a Rm203 Tech. project that we recently started. Ryan, who recently joined our (small) team of nerds decided he wanted to mod his 360 and the natural choice was a Monster Energy theme since it is his favorite drink, and gamer fuel. The following photos taken by Quentin (who else?) document the progress.

The final product will be lit with green LEDs and attached to Ryan's 360.

Efficiency

2008-11-29T18:39:00.000-08:00

As a followup from the last post, here is the efficiency of the coilgun as a percentage in a pie chart. The small blue wedge is the output, the large green represents the energy lost.

The total input energy is 582.12 joules, and output is 15.31 joules kinetic

This second graphic illustrates the data presented in the last post. The number beneath each bar is the length of the projectile and the bar's height is the velocity in ft/s. These data are from the Mark7 which included shielding on the solenoid. For exact measurements please refer data presented in the last post.

M6 Projectile Velocity Tests

2008-10-12T11:19:00.000-07:00

To determine the speed of the projectiles, we fired the gun in front of a ruler and took a 1/4 second exposure with a flash strobing at 100Hz. Please note that we factored the distance between the projectile and the ruler into our calculations. The ruler markings are 1/4 inch and if this distance is used calculation yields a higher result. To correct for this, we used the ruler function in Photoshop CS3 Extended

Data from tests:
Length........Average Speed
2"................82.1
2.5".............76.9
1.5".............42.9
speeds in feet per second

2 inch flat ended projectile

2.5 inch sharpened projectile

1.5 inch flat ended projectile

Photos © Quentin Swager

Coilgun Schematic

2008-10-11T12:24:00.001-07:00

This is a schematic for the coilgun, it does not include the power supply circuit (V1)

[click on the photo for a bigger, more readable version]

M8 Barrel and Ammunition

2008-10-10T15:29:00.000-07:00

(above) The new barrel and the new ammunition

The barrel is 5/16" OD brass tubing, with a wall thickness of .029"
The ammunition is 1/4" mild steel, the clearance between the projectile and barrel is 4.5 thousands of an inch.

Photos by Quentin Swager

Coilgun Mark 8 update

2008-09-27T16:54:00.001-07:00

Yes, the pride and joy of R203 Technology is still being improved. The changes that are underway are in their early stages, however, they are big changes. Just to give a hint of what is to come, a new barrel is on its way, new coils will be wound, and pictured below, a new grip frame is being employed.

Does your external HDD overheat?

2008-09-10T11:21:00.000-07:00

When the fan on Quentin's external died, he wasn't satisfied with me repairing the old fan, so here's what we did...

It wouldn't have been complete without blue LED's.

Quentin took these photos :)

Coilgun with grip frame and "carry case"

2008-09-08T18:36:00.000-07:00

Transistor Array

2008-04-12T10:06:00.000-07:00

With the heatsinks you'd think it could handle a lot of power. Well... I tried to see how much current I could draw from one channel. I got 25 mA. One channel powered a motor easily, in previous tests. I'll have to try a few more things. It could be a less-than-ideal motor I used most recently. We'll see.

Color Organ Update

2008-04-05T20:49:00.000-07:00

This video shows all three channels working. The left light is bass, the middle is mid-range and the right is treble.

The bandpass is still on the breadboard. The display you see is actually pulse-width modulation controlled by the signal from the filters.

To Do:
Put bandpass filter on perf-board.

set up transistor array.

Obtain potentiometers, switches, status lights and various other components.

Color Organ update

2008-04-03T19:27:00.000-07:00

I have made progress on the color organ, finally.

I have tested the preamp, which is now passing the signal. I had to use a different opamp. I was originally using the LM1453, for the preamp I am now using the LM358P.

I have tested the high-pass and low-pass filters, they are working.

I have prototyped the band-pass filter, and it appears to be working.

Now I need to:
Test all filters on the transistors to make sure they are working correctly

Build the bandpass filter on the board and test.

Test Results:
Here is some video from the oscilloscope.

Color Organ status

2008-04-02T09:14:00.000-07:00

The color organ board is mostly done, I haven't worked on it for a while, but the problem I am currently trying to overcome is an issue with the preamp.

I have tested the 3 PWM channels and they work.

I have tested the preamp, which is not passing the signal. [This is my current problem]

I have not tested the high-pass and low-pass filters

I have not built or prototyped the band-pass filter

I'm going to troubleshoot the preamp and see if I can get it working. More info when I have it.

Color Organ Update

2008-02-10T22:29:00.001-08:00

Over the weekend I was able to put most of the color organ onto perf-board. One op-amp is not in its socket, and one filter isn't complete yet. The wires that leave the board go to potentiometers, input, power transistors and switches.

Color Organ

2008-02-04T15:20:00.000-08:00

I am working on a color organ. It will accept audio input, or simply allow the user to adjust the power output by pulse width modulation. hopefully it will also have channels that can switch AC for even more spectacular possibilities.

Another non-coil gun post

2008-01-20T14:05:00.000-08:00

Apologies for the poor quality

This is a video of a circuit that takes the output of an audio jack and runs it through a transformer, the AC electricity coming out of the transformer is fed through a bridge rectifier that turns the signal into DC. This is pulsed DC and can be fed into capacitors and use to power things. (Note: only very small amounts of electricity are available from an audio port) In this video a white LED is connected without capacitors so that the LED pulses with the music.

New Projectile

2008-01-15T21:10:00.001-08:00

Yes this projectile has some inefficiency due to the rounded end which reduces magnetic coupling, but it is also sharp *malevolent laughter* and so it is aerodynamic.

As mentioned earlier we have done some refined tests and pictures and data are to come.

Photo thanks to Quentin Swager

Fun with a disposable camera

2008-01-09T17:54:00.000-08:00

So... The next semester has began, and so has the new year.

Quentin set up a vastly more accurate method of measuring the projectile speed using his camera equipment. Pictures and data to come, but for now here's what I did most recently.

I had a disposable camera on hand and wanted to do something with the flash charging circuit. Since these have been used as pranks to shock people, I thought, "Why tether your shocking power to a door knob? Why not make it portable?" So I did just that.

As a sidenote: electricity is dangerous, don't try this stuff unless you know what you're doing.

News

2007-11-30T10:12:00.000-08:00

You might be interested. The other day we used the gun as a pile driver and pounded a SCREW into a 2x4 it took two shots to put most of it into the board.

We've made 2 new projectiles, pictures to come later. We've also added a grip frame from a paintball gun and wired the switch in so there is a trigger on the gun. I painted it black the other day, so it looks a little less "ghetto"

Mark VI

2007-11-19T23:49:00.000-08:00

MARK VI REPORT

2007-11-18T16:07:00.000-08:00

Yes MARK VI is finished, and working beautifully. It is the most powerful version yet, and I have some pretty interesting footage that I will upload once it is edited. Just today we built a case for the SCR switch and its necessary components. It has a nice big red button for "FIRE."

Video coming shortly (after I finish my homework...)

Charger

2007-11-13T18:19:00.000-08:00

The green light indicates that the power is switched on. The red light indicates that the voltage is at or above the set voltage (charged).

The gauge is Volts X 10.

Photos courtesy of Quentin Swager

SCR and Capacitors

2007-11-13T17:23:00.001-08:00

This is the SCR holder. The power will flow from one plate to the other when turned on. There are insulators on the bolts.

Here are two capacitors connected together.

The photos are courtesy of Quentin Swager

Progress

2007-11-13T12:31:00.000-08:00

The charger case is almost complete. It works great and looks really neat. I'll put pictures up as soon as we have some.

Last Saturday we machined some aluminum to connect 2 caps, and to hold the SCR.

We have calculated the peak current for the coil dry firing with two capacitors, and it is well within the capabilities of the SCR.

One problem we may have is the pulse length with 2 caps and an SCR - because unlike an IGBT, the SCR switches off after all the power is spent. We can't control the pulse-length like we can with the IGBT, but we can handle more amperage.

In summary, we will probably be able to test again within a week. Hopefully it will be more powerful (it should be) but like I mentioned; the pulse-length may be so long that the magnetic field begins to pull the projectile back into the solenoid. If the field is still present when the projectile passes the center of the solenoid we would have losses.

As usual - when we test, I will have a video of it on here. My videocamera died so I will borrow one, but I promise another video.

Status/Parts Update

2007-11-03T13:25:00.000-07:00

We now have the SCR (which is physically much smaller than we assumed).

We are working on the case for the charger/power supply.

We are calculating inductance of the coil and verifying amperage so currents can be well within the capacities of various components.

I'll include a picture to illustrate the size of the SCR.

Parts update

2007-10-17T16:59:00.000-07:00

Parts recently acquired/ acquiring

1. SCR Thyristor (9000amps pulse)

2. nuts and bolts

3. Spacers

Here is the SCR

Photo credit: Semikron

Coilgun Mark V

2007-10-10T07:05:00.001-07:00

Mark V Pictures

2007-10-09T22:21:00.001-07:00

The Gauss gun was shot point-blank into this 2x4

This is the imprint on the backside of a can after the (blunt) projectile put a hole in the other side.

Note that the pattern of the cut from the band-saw is visible

Mark IV could not penetrate the bottom of a can, here Mark V punches a hole clean through with one of the most recently pictured projectiles.

Photos thanks to the illustrious Quentin Swager

Parts Update

2007-10-09T14:40:00.000-07:00

The IGBTs have arrived!

New Projectiles

2007-10-07T23:33:00.000-07:00

To clarify, these new projectiles are cut from a 3/8" (or so) anchor bolt. They measure 0.5, 1, 1.5 and 2 inches long (approx)

These have not been tested yet, you can bet on a video when we test next .

Photos courtesy of Quentin Swager

Status update

2007-10-07T21:42:00.000-07:00

The power supply is complete and working exactly as planned, thanks to Chris' skills.

The power supply is turned on and off by a relay, based on the voltage. This voltage is controlled by the red dial. This is designed so that we can set different voltages and avoid overcharging. The unit also features a master on/off switch and a way it can be turned off with a micro-controller.

These are the new projectiles - we will be testing the effectiveness of different coil/projectile size ratios.

Photos are thanks to Quentin Swager

Status Update

2007-10-05T11:26:00.000-07:00

As you may know, the charging circuit (120VAC to 500VDC) has been completed for some time. The control circuit, however is still under construction. Since the charging circuit is fed through a relay, we can construct another circuit to control when the charger turns on and off. This will charge the capacitors to a specified voltage (controlled by a dial) and keep it there.

I have been working on it this week and
I'd say that is halfway finished by now.

Parts update

2007-10-01T19:09:00.000-07:00

So far this week we have obtained or are in the process of obtaining the following parts:

1 - Sheet of polycarbonate - for mounting circuitry

2 - long 7/16" anchor bolts - for projectiles

3 - Two Powerex IGBTs 1200V 600A - for switching power to the coil(s)

If you are wondering, an IGBT is an

Isolated
Gate
Bipolar
Transistor
(a solid-state switch)

This information is provided (of course) from Chris' electronics manual of a brain.

Mark IV - Pictures

2007-09-29T23:21:00.000-07:00

1 - The projectile - we need improvement in this area

2 - Projectile in Dr. Pepper can

3 - Above view

Credit: photos by Quentin Swager

Mark IV

2007-09-29T22:28:00.000-07:00

This version includes:

New higher-capacity charging circuit (on perf-board this time)
Relay that switches charger on and off
5 layer AWG 12 coil
PVC barrel
450V 3,300 uF Cap.

It was able to propel a sharpened bolt into an aluminum can, stopping at the head of the bolt.

Chris has created an analog voltmeter for the capacitor(s).

We are in the process of getting a heavy duty IGBT for switching power to the coil(s), this will eliminate arcing and increase efficiency and control. As a side note, we tested a 60A, 500V IGBT and it exploded, proving that we need one of higher capacity.

Mark II

2007-09-27T21:53:00.001-07:00

Note: Mark IV is currently in progress

Status

2007-09-24T19:55:00.000-07:00

The current coilgun (Mark IV) in progress uses a single 5 layer 12AWG coil with pvc pipe. Currently Chris is developing a permanent charging system.

The capacitors we have available are 450 volt 3,300 micro-farads.

We have eight of these.