Bypass Caps

The questions is; where to put Bypass caps in the circuit?

Next to a analog or digital device of course, between the VCC and VSS pins.

But, this is only really easy to do on; push boards, protoboards, deadbug or experimental circuits, just push the caps in, and/or solder as necessary.

But then, if you are actually planning to build a complex PCB's (i.e. more than a few devices), it is a lot of work to make sure the right cap (as per the schematic) is next to its associated device. All of the bypass caps are connected in parallel to the same supply and ground rails (i.e. VCC and VSS), therefore on the initial PCB layout they are connected to the same "rats nest" and not really associated with a particular device. The unscrambling task is even more difficult, because bypass caps are typically all the same value.

Some designers just scatter the bypass caps around the board next to a likely devices. Other (better) designers take the time to place the correct bypass caps near its associated devise, as per the schematic - this can be a lot of work!

But, does it matter? - it is only a reference symbol printed on PCB in silkscreen. To me; "Yes, it does matter". And therefore, I make sure the correct bypass cap is next to its associated device as per the schematic.

Schematic Diagram

I use the following technique to make the PCB layout of bypass caps and associated devices easy. On the schematic, I insert a "Zero Ohm" resistor in the supply line (VCC) that feeds each bypass cap. Now regardless of PCB layout software that is used, the initial "rats nest" will suggest close layout of the correct bypass cap with its associated device. From PCB layout perspective, the Bypass caps are NOT directly attached to the VCC rail, but instead, it is connected to the "Zero Ohm" resistor which is connected to the power VCC rail. The associated "Zero Ohm" series resistor is easily located and placed next to its bypass cap (because it is in series and not parallel on the schematic). Its a simple trick that just makes PCB layout much-much easier!

PCB Layout

Also, for most low current devices where 6 mil traces are typical, I use a 0201 "Zero Ohm" device footprint. Instead of an actual device, a simple solder bridge is all that is needed to make the connection. And, this technique makes troubleshooting a new designs all that much easier. A troubling device can be removed from the circuit with a little solder wick.

As Manufactured

As seen in the schematic diagram, B2 is the symbol that I created for the solder bridge.

This technique; may, or may not, be useful for Production Products, but for the Hobbyist it works great!

BTW, I also put in 0201 "Zero Ohm" in all I2C lines, next to each I2C device, for easy initial testing. A bad I2C device can easily take the entire bus down - which is not fun to troubleshoot.

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UPDATE

Note: I am looking for a more appropriate footprint for an easy to use solder jumper.

A "Zero Ohm" resistor can also be used to enforce and make easier a "star grounding" system for a set of parts. Connect the circuits star grounds to one end of the "Zero Ohm" resistor and the real ground to the other. For a PCB layout, a star isolated ground plane can also be attached to the same point (i.e., multiple isolated ground planes can be used on the same board).

UPDATE 2

I am considering one of the following for future project Solder Jumpers, some additional function and use evaluation is needed.

Proposed Solder Jumpers

• Jumper SJ2 is about 100 mil diameter with 10 mill isolation.
• Jumper SJ1 is a 70x40 mil rectangle with 6 mil isolation.

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A Self Photo from Mars - at 41.5M Pixels

OK, this is another Curiosity photo, But,  it is an Absolutely Amazing High Resolution Self Photo taken on Mars.

http://www.nasa.gov/images/content/703574main_MSL%20self-portrait%20pia16239%2020121101_full.jpg
also see
http://mars.jpl.nasa.gov/msl/multimedia/images/?ImageID=4845

This photo was stitch together from many smaller photos. The Detail is stunning at 5463 x 7595 pixels that is a 41.5M pixel image !!

Go to the link, it may take a while to download, but zoom in and pan around to see the high resolution details !

For Ham Radio QRP, Hardware, and Robotic Geeks - it does not get better than this !

Thanks JPL and NASA !!

Now we need someone to explain all of the devices on the Rover, like:

• What is that waveguide driven vertical antenna on the back left-side of the rover (upper right in the photo)?
• What are thosee funnel shaped cones on the front? Are those small linear actuators used for positioning?
• What is that Large Grey Cross bar on the Top?

And, maybe someone will make a Trimble (Google) Sketchup of the Rover ?

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More Fun with 3D

I recently updated a previous post showing the outside view from my loft. The original photo was taken on Sep 16th, and now the second was taken on Nov 2ed, These photos are arranged for Cross-Eye 3D viewing (CE3D). I took this last photo just because of the very bright fall colors. Not wanting to bore my blog readers with "just another one of my 3D photos", I decided to attach it to a previous blog page (nobody other than myself will really notice).

But, I inadvertently discovered a very interesting artifact of publishing them on the same post page; after clicking on the first image for the expanded browser view, you can quickly flip between the two views with a gentle roll of the middle mouse button. For this scene, only the season's colors change (and maybe a slight unintended zoom scale). The effect can be seen in 2D, but it is not nearly as dramatic as seen in 3D.

Even with only two photos, the time lapse photography is very intriguing in 3D. I now plan to take similar photos at regular intervals to expand the time frame. Maybe a new photo set each week.

I use ImageMagick to combine the Right and Left images into a CE3D view. For example:

convert R.JPG L.JPG -splice 10x0 +append -chop 10x0 -resize 1200  CE3D.JPG

Note: the Right/Left order of the two original images is very important.

Oh, I have been viewing so many Cross-Eye 3D Viewed photos that I now can quickly switch to Cross-Eye 3D mode and without Eye Strain. The images are photos that I have taken, or created from the raw Mars Mission photos, and others found on the web,  I view most online images from about 30 inches (distance to the computer screen).

I like 3D photos, they provide so much more revealing detail, that just can not be perceived in 2D. It is similar to the different listening pleasures of; an AM Mono broadcast, and good a FM Stereo Music Station.

I plan to do a lot more with this interesting viewing mode.

Here is an interesting Cross-Eye 3D Video that may help explain the viewing technique.

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I Abandoned Nvidia for My Ham Station Computers

I use Ubuntu on my Ham Shack Computers, and have recently installed the new revision 12.04. All of my Ham Applications seem to work much better with this new release, the sound system seems to work predictably and correctly.

But, I gave up on graphics, after several days of frustration trying to get my Nvidia G7000 Graphics Card to work in the 3D mode on Ubuntu (see previous post).

I decided to try to replace the "Nvidia Graphics Card" with my Son's discarded and dying "ATI Radeon HD 5450" graphics card. A little repair of the card's fan and a little micro surgery was necessary to bring the "ATI Radeon" roaring back to life.

I installed the repaired ATI Radeon card, rebooted and it worked as expected in 2D mode. I then installed the suggested Drivers, and rebooted, - it just worked!  -  No hassle nor pain, Ubuntu graphics now runs in the 3D mode!

After much research, I found that; due to lack of manufactures supported or open drivers, the Nvidia Cards are not well supported for use with Ubuntu. For my other system upgrades, I am going to abandon Nvidia in favor of ATI.

I really like the new 3D Graphics menus and workspaces!

Note: The menus do not actually appear in 3D, but Ubuntu does use the graphics card's 3D processor to quickly and dynamically display the menus and workspaces. In 2D mode, some functionality is not available.

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My Update to Ubuntu 12.04

Last weekend my Son, requested help installing Ubuntu on one of his old Laptops and an old Workstation. He has only used MS up until now. I have always used some flavor of Linux for most of my systems from the beginning  (as far back as Minux). For my Son, I suggested Ubuntu as that is what I have been using for the last few years, and it is easy to admin!

I have been using Ubuntu 10.04 LTS since 2010 (as implied by the Rev Number). The LTS suffix means that the Rev has what is called "Long Term Support" from developers. I like LTS as it is more likely to be stable. Because I am mostly satisfied with my Ubuntu installation, I had not kept up with the latest news of additional releases. But, for my Son new installations I wanted to review the latest available release. To my pleasant surprise the current Rev of Ubuntu is 12.04 with LTS.  I should have known as it is a even numbered release. For those that do not know, the first two digits of the Rev number is the year and the last is the month. The developers plan is an LTS for each even numbered year.

To me this is good news, I could install Ubuntu 12.04 on my Son's fresh wiped systems, before I would have to figure out how to do the same on my established systems.

We downloaded the ~700MByte Ubuntu 12.04.1 ISO file, to my Laptop and proceeded to transfer the file to a USB  thumb drive. But we could not get his older workstation to boot from the USB. The solution should be simple; transfer the image to CD, but that did not work, the image is larger than a CD. A DVD is necessary, but that is OK as my laptop contains a DVD burner. The image was transferred onto the DVD, but then that did not work as the Workstation and Laptop could not use the image written at high speed. With some research,  the recommended speed was below 4X. A new DVD was burned at low speed. The Laptop install process was a little slow, but going well enough that a second DVD was burned to use with the Workstation. The Workstation was much faster than the Laptop and finished first. We then had fun playing and admin'ing the two new systems.

That night when I got home (about 10pm) I decided that was easy and therefore I should update my (established) Laptop. It would not be a fresh install, but an update, preserving as all of the user data. At about 3:30am when I went to bed,  I had still not completed the task. The next morning all went well and now I have a Laptop running Ubuntu 12.04.1 LTS.

I tried to do the same with one of my Workstation, to make a long story short, I attempted to update the system twice and scratch installed it four additional times, my user data was on another disk and therefore a install was not a great lose. In general, the problem and answers were: Build from DVD and not try to use an USB, the NVIDIA video card that the Workstation contains is not supported very well. Ubuntu 12.04 uses what is called Unity for windowing, the menus and workspaces are best viewed in the 3D mode, NVIDA 3D is not currently supported by Ubuntu.

Self Image

But, after many hours, I have Ubuntu 12.04.1 on two system, and to my surprise the major thing that I have always complained about Ubuntu, appears to be FIXED. Before at rev 10.40, the "sound" system seemed to never worked right, now it seem to just work -Yeah!

I am going to like Ubuntu 12.04.1 :-)

More details and progress may follow.

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Litter Photographed on Mars

Sixty five days after landing, "Litter" was photographed on Mars.

The Litter appears to be a plastic tape fragment. Curosity's arm hand camera took the following close-up photo.

Litter found on Mars

The JPL crew is trying to determine the litter's origin. They are assuming it fell off of Curosity, and wondering "how or if " system integrity has been compromise. Read the full story here or see a video (mov) here.

It would be interesting to know if it was dropped here by Curosity, or debris scattered here as part of the Landing 65 days ago.

My questions are:

• Did they bring a Trash Sack to collect their own Litter?
• Do they plan to attempt retrieving the Litter?
• How long do they think plastic will last on Mars?

Remember on Earth, the rule is:
Pack it in - Pack it out!

Ham Radio

I will get back to "Ham Radio Blogging" soon, I have several projects in the works, two PCB's being manufactured, and currently having fun attempting to gennerating PSK31 with the Prop.

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Curiosity's First Major Rock Photos

On Sol0038 Curiosity took the first photo of a major rock along its path. Although, it may be just a layer of hard crusted dirt.

Curiosity's First Major Rock

From this and previous photos, it appears the Curiosity has been climbing up a very slight slope, with a some distance to go to the crest.

On Sol0040 it appears that Curiosity has almost made it to the the crest of the rise and then it will be going down hill for a while.

Near the Crest of the Rise
On the way to Mount Sharp

The slope of the land is not real apparent in the individual 2D images, only in 3D is it obvious.

Disclaimer: Raw Curiosity photos are available from the NASA web site,  Cross-Eyed Images above were constructed by Eldon Brown, with Image-Magick.

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More Local 3D Views

I have been playing some more with Cross-Eye 3D photos. This time the subject is the view out of my loft window. The lighting is not very good, but there are two Deer in the frame. They are very small and seen; below, and slightly to the right of the closest branch of the foreground tree. One is forward a little and laying down, the other is standing a little further back, looking over her left shoulder.

Deer Seen From My Loft
Sep 16, 2012

If I had known the deer were in the shot, I would have tried to use some zoom.

I found a easy way to take the two photos, slide the camera along a small angle of wood or something that is stable. My camera sits nicely and square against a supporting back lip. Between the two shots, I slid the camera about 3 or 4 inches.

Note: if you do not look at this in 3D, you may not determine the branch that I refereed to and therefore may not be able to see the Deer.

Here is an interesting Cross-Eye 3D Video that may help explain the viewing technique.

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UPDATE:

Fall is in the air:

Nov 2, 2012

Nov 8, 2012

Nov 15, 2012

Nov 25, 2012 13:15

Dec 18, 2012 10:00
First Snow

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Many Similar Hobbies

I have enjoyed the Amateur Radio Hobby since I was in High School and like most fellow Hams, I have met many friends because of it.

There appears to be similar theme among all those that play with radios; They all seem to enjoy additional and a similar set of hobbies. The second most represented hobby is Aviation, either Full Size and/or RC Scale.

For 12 years, I flew my full size and very fast Cessna 182 RG - N5196R camping around the Pacific Northwest and I enjoyed it immensely.

5196R - Flying near Redline
165 Knots (190 mph) at 30 feet
Concrete Wa - 1994 Flyin

Much earlier, my Son and I flew U-control for a while and then gravitated to RC flying back in the old 27MHz days. Of course we had to upgrade to 72MHz to avoid control problems, and all the new stuff was coming out on 72MHz. We could still find simple and inexpensive RC Transmitter and Receivers. Motors seemed expensive at the time at about $40 for a Cox 0.25. But we saved a lot on scratch and simple kit planes. Personally, I never liked; the fuel, oily clean-up and all of the mess associated with powered RC flight. We gravitated in another direction to Sailplanes. We flew at a remote site, where High Start Lines could be used.

We (mostly I) then left the RC hobby spending more time working for a living and flying my Cessna. My son continued with his interest of RC Flying and still has bits and pieces of some of our previous RC aircraft. He expanded into the expensive ($600) Computer Controlled Transmitters and the new GHz frequencies. I considered it all to be too expensive to keep up with the advances. . . .

until recently.

I found and purchased a new 2GHz 6 Channel TecTic Transmitter and Receiver for only $99 from TowerHobbies.com. I purchased two sets, for less than one typical Big Brand Named systems. It is a nice setup. The mode-2 TecTic Transmitter is "wireless" buddy cord Ready, easy to set up and use, at the touch of a switch. I am rusty, and still need a little refresher-help when I attempt to fly.

I still like to fly Sailplanes, but now they are electric powered as a motor glider, I now have the Vista Sailplane ARF. Even with my re-newed interest in RC flying. Lack of time, and assistance has slowed my re-learning process. My two planes set in the shop, with the batteries draining from lack of use.

Mark, of BrainWagon.com Fame, has posted several nice blog entries; here and here, that has rekindled my interest in RC Flying. Mark's latest adventure is here.

The new electric motors, batteries and servos do not seem expensive for scratch built foamies and park flyers.

I also found a $15 Flight Simulator setup from HobbyKing.com, now I can continue to practice even when it is raining here in the Seattle area. I do plan to spend more time RC flying (and/or fly fishing) this next year.

With my dog "Tess", Ham Radio, RC Flying (and Fly Fishing), I may not have time enough time for all that I want to do - but it will be . . . fun trying :-)

Note: I just found out that my Cessna 182 (non-RG) is available as a RC Aircraft, . . . it could be fun,  . . . but it would not be the same!!

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My Prop LU Implementation

My forum links are archived here for follow up reference.

Prop LU via Indexed Methods
http://forums.parallax.com/showthread.php?142348-A-quot-Gem-quot-found-in-the-Prop-Q-amp-A

And here, Prop Load Average
http://forums.parallax.com/showthread.php?142379-SPIN-Task-Switching-for-us-Prop-Noobies

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