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91  Forum 2005-2010 (read only) / Bar Sport / Re: Cornell Universal Hand Gripper on: October 28, 2010, 01:12:51 pm

I work for an automation company and we work with grippers of all kinds . . . but I have never seen anything like this before.
92  Forum 2005-2010 (read only) / Bar Sport / Re: Compressed Air Pressure Meter on: September 30, 2010, 09:02:11 am

What gave you the idea that the Harbor Freight Digital Air Pressure Gauge measured “speed”?

It is an air pressure gauge, not an airspeed gauge.

Take a look at the manual:

From the looks of it . . . and I have physically examined it since I was contemplating its suitability as a hackable device . . . it should be as easy as any other small electronic device to hack.

Open up the box and try to pick of the appropriate signal going to the LCD then decode it to your hearts content.
93  Forum 2005-2010 (read only) / Bar Sport / Re: Compressed Air Pressure Meter on: September 24, 2010, 03:36:39 pm

I think that this little $15 beauty from Harbor Freight might be the way to go:

While it is a digital regulator, I think that it will display the actual pressure delivered rather than the pressure set. You could crank it up to your maximum safe working pressure by setting it with a high-pressure shop source then install it into your model rocket system and just watch the gauge.

Or you could Arduinoize it and hack into the display to get digital signals and relay them to your Arduino.
94  Forum 2005-2010 (read only) / Bar Sport / Re: "Directional Switch" Design on: October 11, 2010, 12:33:45 am

If you want to do this without the use of a microcontroller, then I think that you will need to use a mechanical cam to activate the switch.

You could do this by cutting a tapered cam profile in a long piece of plastic or wood that is mounted to the drawer. The cam would need to be hinged in such a way to allow the cam follower (attached to a micro switch) to activate the switch when the drawer is being closed . . . yet take a slightly different path (bypassing the cam) when the drawer is being opened.

Some ball point pens that operate by pushing the button once to extend and pushing it a second time to retract, work on a similar principle.
95  Forum 2005-2010 (read only) / Bar Sport / Re: Scavenging parts on: September 09, 2010, 09:20:41 am
I've been personally blessed with the mother lode of all mother lodes . . . my employer has been physically downsizing.

I work in automation and a year ago, we emptied out a small facility a block away and put a lot of their spare parts in storage at my facility. Now we are in the process of moving from the two remaining facilities to one facility that is big enough to house both divisions.

The result as we clean out the storage shelves has been an incredible blessing of sensors, shielded sensor wire, pneumatic cylinders & valves, Lexan polycarbonate sheet, Bosch aluminum strut and hardware.

Perhaps the best pick has been a working vacuum pump.

The hardest part has been sneaking all this stuff into the house and down into the workshop without my wife seeing more junk coming in.

I have also done well doing a little scavenging for old VCR's, printers, etc on “garbage night” in years past.

Unfortunate for me . . . but better for the environment, in my area all E-waste must go to a special recycling centre . . . however since all incoming E-waste is broken down and ground up for automated material separation, they will not let people like me come in and pick through it; claiming liability issues and such. Damm lawyers!
96  Forum 2005-2010 (read only) / Bar Sport / Re: mm verses inches on: September 09, 2010, 03:28:34 pm
In Canada we have spent the last 40 years integrating and there are only a few old Imperial hanger-ons like:

  • Houses are still quoted in square feet
  • Lumber is still sold as 2x4's and plywood as 4x8's (feet for the later)
All liquid is sold in liters and fuel consumption is quoted in litres/per 100 kilometers.

The only parts of the metric system that most of us Cannuks have still not quite got the hang of are hectors and kilopascals.

Most importantly, although bottled beer can be bought in 6 packs (aka the Poverty Pack), or a 12 pack (aka a Picnic Pack) the basic unit of beer is 24 bottles in a case and the prevailing belief here is:

24 bottles in a case and 24 hours in a day . . . coincidence(?) . . . I think not!
97  Forum 2005-2010 (read only) / Bar Sport / Re: Ideas you'll never make on: July 28, 2010, 09:15:42 am
Pinky: "Gee, Brain, what do you want to do tonight with our Arduino powers?"

The Brain: "The same thing we do every night, Pinky—try to take over the world!"

Pinky: "Zort!"
98  Forum 2005-2010 (read only) / Bar Sport / Re: What was your first OS? on: May 02, 2010, 09:01:22 pm
Yes the ol' Timex Sinclair 1000 (the North American designation for the ZX-81) now that was old school. My brother and I shared it and after bumping against its miniscule 2K RAM every time we tried to use it, we splurged on the monstrous 16k RAM module. For long term storage, you plugged the thing into a cassette tape recorder and "saved" your program to "tape."

Probably our favorite program was a lunar lander game that came listed in the manual. Lots of hard coding and 100% typing accuracy required as there was no debugging function.

Of all the computer hardware that I have owned over the past 20-30 years . . . that is the only piece that I wish I still owned even if it wasn't good for anything but a shelf trophy.
99  Forum 2005-2010 (read only) / Bar Sport / Re: Hello from the... thread on: June 01, 2010, 07:42:46 am
Hello from CaptainBalsa in Cambridge, Ontario, Canada
100  Forum 2005-2010 (read only) / Bar Sport / Re: Why are DIPs so inneficient compared to SMDs? on: June 07, 2010, 02:22:27 pm
As someone has already suggested . . . hold onto your DIPs while you can because the time that they will start disappearing is now.

Most of my electronic hobby work centre's around science based instrumentation (seismographs, mircobarographs, monitoring the Aurora Borealis or electrical storms). While there are a lot of pre-existing schematics for these kinds of projects, most of them are more than 10 years old and consequently many of the IC's, transistors and misc discrete components are obsolete. If you are lucky, then they might be available in SMD as a sample . . . however, in many cases you are just SOL.

That's where the Arduino comes in!

My current project is a microbarograph which is an instrument that monitors infrasonic (sound waves far below normal hearing range) energy.

The circuit involves a simple heater control that turns on when triggered by a low level sensor monitoring of opaque liquid in a manometer (bent u-shaped glass tube). The second part of the circuit is a simple instrumentation amplifier that monitors the actual temperature fluctuation that triggers the heater circuit. These temperature fluctuations form the devices output that can be data logged.

Several of the required components are extremely difficult to find, but the functions of both circuits are relatively easy to accomplish with an Arduino and some relatively easy programming.

Without the Arduino, some of these circuits would require re-engineering by someone a lot more knowledgeable than me.
101  Forum 2005-2010 (read only) / Bar Sport / Re: Anyone here with a model bridge building hobby? on: May 11, 2010, 08:24:14 am
I've been sitting on the sidelines watching this thread to see what might surface and felt that it was time to add my 2-cents worth.

The best job I ever had was as a professional model builder (20 years ago) for a consulting engineering firm My job was to build scale models of bridges and buildings for use in wind tunnel and snow flume analysis prior to the expensive construction of full scale (real world) ones.

Most of the study buildings were made of sheet acrylic or polycarbonate with some small scale details made from sheet styrene.

The bridges where made from various combinations of balsa, thin aviation grade plywood, acrylic, polycarbonate, styrene, brass and aluminum; with the choice of material based on the type of the part, its load bearing requirement and the level of scale detail required.

Truss work was usually balsa . . . sometimes laser cut in a truss-like pattern, whereas roadway surfaces might be thin (1/32 - 1/16” thick) plywood. Piers might be acrylic, polycarbonate of in some cases machined aluminum. Suspension cables were made from monofilament line, very small gauge wire or in one case human hair . . . yes human hair because of its tensile strength vs diameter. We also made extensive use of CA glues and epoxy for bonding.

Pracas, your choice of material should be based on a number of factors:

     *your desired aesthetic (a bridge made from popsicle sticks looks a lot different than one made of toothpicks or balsa)

     *your materials budget and materials availability

     *your capabilities as a model builder

If you do not have much experience working with tools and these types of materials, then choose a simple project made from simple inexpensive materials so that you do not get frustrated and give up midway through.
102  Forum 2005-2010 (read only) / Bar Sport / Re: Production of Plastic Enclosures? on: April 17, 2010, 12:14:41 am
Well done Jasper!

Although I have been working in automation for the past 6-7 years, I spent the previous 25 years in product development for the injection moulding and prototype industries.

During that previous life, I frequently . . . as in several times per week, met people who were disappointed to learn about the cost and complexity of even low-volume injection moulding.

However as Jasper has so well illustrated, and a few others have suggested; there are some alternatives that work well for low volume requirements.

Possible manufacturing methods for the production of low volume enclosures:

•      Fabrication (cutting and gluing) from flat stock . . . best for very low production runs

•      Additive fabrication using various rapid prototyping methods (SLA, SLS, RepRap, MakerBot, etc.) . . . also best used for very low production runs

•      Machining from solid blocks . . . depending upon the complexity of the enclosure, material selection and production volumes, CNC machining can sometimes be a cost effective method

•      Casting using simple moulds (usually RTV moulds cast from master models produced by fabrication and/or machining). Today there is a wide assortment of both casting resins (acrylics and urethanes primarily) and RTV (Room Temperature Vulcanizing) materials

•      Low volume injection moulding from soft tooling. Soft tooling ranges from aluminum reinforced cast tooling epoxies (not recommended) to temporary aluminum cores and cavities.

•      Custom machining of OTS (Off The Shelf) enclosures . . . many enclosure manufacturers offer custom machining, painting, membrane switches, Lamacoid services, etc; to help create a custom look

•      Unfortunately, vacuum forming sheet stock over temporary or permanent moulds is frequently overlooked; however from the standpoint of tooling cost, tooling delivery, part cost and design freedom this method has a lot to offer . . . most notably in large enclosures

At any rate it is important to understand, that like any engineering endeavor there are some compromises that are required. Most notably, every one of the above manufacturing methods placing unique technical requirements related to product design (form), material properties and performance.

It is not enough to draw an interesting shape and then go shopping for the cheapest price. The first step is to establish the production quantities; product price point and delivery time to market . . . these factors will be the largest influence on what manufacturing method will be best suited to the project.

Once the quantities, price and production method have been established, then the product can be designed . . . taking into account the limitations of material selection, wall thickness, corner radii, mounting bosses, cooling slots, etc. required by the chosen manufacturing method.

Mike Mc, unfortunately all of my contacts from the industry are on the other side of the big pond so I cannot make any recommendations regarding suppliers, but I would think that there would be some businesses in the UK that could do the work. Usually it is best to do this kind of work locally as issues can be resolved more easily than if you are working long distance.

103  Forum 2005-2010 (read only) / Bar Sport / Re: home electronic parts inventory option? on: April 12, 2010, 12:13:20 pm
see if I can salvage the good stuff

For the past 30 years I have worked as a model builder, product designer, sales manager and project manager in the prototype, injection moulding and automation industries.

Consequently I come into contact with a lot of interesting customer supplied materials that are used for testing, but then discarded at the end of the project. Over the years I have rescued from the dumpster 1/32” dia aircraft cable, flexible 1/32” Baltic birch plywood, 100 feet of A2 hard spring steel, Teflon coated fabric (for high temperature applications), 1000's of O-rings (only in one or two sizes), bits and pieces of high-temp ceramics, Delrin, nylon, etc. . . . plus so many other materials that I couldn't list them all.

They are all crudely stored (but not catalogued) in banker's boxes and large Rubbermaid bins. Can't have the wife sorting through all that, she'd never believe that I hadn't paid for all that stuff.
104  Forum 2005-2010 (read only) / Bar Sport / Re: home electronic parts inventory option? on: April 12, 2010, 11:15:50 am

I was cleaning up my workshop this weekend . . . the first hour plus was cleaning up the mess left by my teenager . . . the next two hours was spent sorting and tossing enough stuff to fill two garbage bags and I am still not done.

My wife was just dying to join in and really show me how to do it, but there was NO way I was going to let her in to see how much stuff I really have squirreled away down there. Even my teenager is constantly amazed to see me pull something out of nowhere that he had never found before.
105  Forum 2005-2010 (read only) / Bar Sport / Re: home electronic parts inventory option? on: April 12, 2010, 09:37:15 am
I also tend to buy parts for several projects at the same time, however long ago I was introduced to two products that when combined have revolutionized how I store and package the various components so that they don't get lost or misplaced or whose original purpose gets forgotten.

The two products are called Sharpie markers and Ziploc freezer bags.

Once I have secreted my new contraband past my wife and safely made it down to my workshop, I label a Ziploc bag with the name of the project and possibly the source; then place the required components into the bag . . . sometimes including a copy of the schematic or magazine article. If I have already acquired a suitable enclosure, I place it in the bag if it is small enough . . . otherwise if it is too large, then I tape the bag of goodies inside the enclosure.

A $1 for a Sharpie and $3 for 25 heavy duty (reusable) Ziploc freezer bags is money well spent and eliminates both confusion and the tendency to buy twice . . . build once.
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