Robotics as a hobby!

First I want make sure everybody understand that this is a newbie question. My expertise is with computers but I decided that I want to
study a little about robotic as a hobby. Now I wonder what kind of artifacts I could craft using robotics that I can not simply buy on stores or at least that are cheapest to craft than purchase. Any examples you could provide me? Of course I understand that many times I will build a device just to understand how it works but if I can create useful everyday items it will be even more fun!
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Welcome to the limitless potential of human brain, electronics and mechanics! You have just entered the enlightened zone! How about starting your understanding of basic robotics with an example to be found in your own home if you have a furnace. Let's walk through this system together as you visualize yourself pushing the thermostat control to 72 degrees. Look inside of the thermostat control on the wall, go inside the plastic cover and you most likely will see a coil of copper-looking metal, and a glass bulb on one end with silver looking liquid. This is the first feedback sensor to your home comfort. As the temperature changes, the metalic coil expands and in expanding changes the angle of the mercury in the glass. If you watch carefully, the angle will reach a level then quickly make that last minute movement that will let gravity take the mercury into the opposite side of the glass. Inside the glass are two little wires sticking up. When the mercury floods them, an electrical circuit has been closed. The operative word here is, from zero to one. Enter the world of digital electronics. The simple switch. Which will lead you to the yellow brick road. But don't stop here. That closing of a circuit will now trigger another set of logical building blocks. First, it will tell the pilot light igniter in your furnace to turn on. To do this, a valve opening the pilot light will open, and an igniter will turn on. Another sensor will detect when the pilot has been turned on, and will signal the igniter that it has done it's job, thank you, now shut up! As the pilot does it's job, another sensor is monitoring the main furnace and will patiently wait for the main gas valve to open, then will make sure the igniter has done it's job. When the main gas is burning, another sensor tells the motor to turn on and keep going while the firebox is lighted thus ensuring heat going into the home and not burning up the furnace, then the home.
If you were to make a flow chart of this system, you will be years ahead of most robotic enthusiasts who see the mechanics as one world and the electronics as another world. You will see the infinite potential of marrying the two brides: electronics/computers to the macho male mechanics, breaking through yet another paradigm leaving human social order in the past.
Robotics allows us to break from the anchors of the past and fly into new space and time constraints. Add artificial intelligence and eventually mechanical learning and you will have a whole new world to explore.
Go ahead, draw a circuit diagram and logical electronic algorythm of a typical home furnace. Then do the same for your automobile engine. Then, on the side, keep a list of your thoughts as you go about this discovery. Sooner or later you will have a list of things that you will convert into a robotic system.
Wayne www.terrasegura.org

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oops... a couple of 'corrections'.... the first scenario of coiled bimetallic ribbon is shrinking with the chilling temperature changes in the house, not expanding as envisioned.
Not a correction, but an addition... the circuit configuration is based on relays, and the diagraming of this circuit would logically be, in guess what? Ladder logic programming. The forerunner to most of all digital logic stuff since the great divide in the mid 50's when the British Overseas Airways Co. (BOAC) and United Airlines signed the document to pursue digital training devices over analogue. Which turned the tide for all future automation innovations. On that day, we went digital.

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That was a fun to read post
Thanks
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but still the question remains: what kind of artifacts I could craft using robotics that I can not simply buy on stores or at least that are cheapest to craft than purchase?
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OK, I challenge you to find a device that will go into your back yard, test soil for acid/alkaline, nutrition, moisture... compare to yearly rainfall and temperatures, then select the exact plant to be sown into the soil for harvest exactly on the even of your next thanksgiving dinner, define the seed, search and find a supplier, order using barcode technology, receive, plant.... along with a grape that can be squeezed into wine and fermented and even chilled with mountain snow.... etc. Go for it!
Also, make sure the device has enough power at all times, so it will back into a plug, sense the whole environment confirming humidity, temperature, weather conditions and change programming accordingly.
More?
PS - Ill buy the first model!!!!
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Realistically, probably nothing much that's useful. A robotics hobby is a form of education and entertainment; it's not something you do to make things you couldn't otherwise get. Think of it like model railroading, or RC car racing, or LEGO building. In all these cases -- as in robotics for the most part -- to ask, "what is it good for?" is rather missing the point.
Of course, in a very specific sense, each robot you create will be a unique one-of-a-kind model, not available in any store.
HTH, - Joe
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Great answer thanks!
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I am speaking as a programmer and not a robotic's builder. (I am a wannabe there.) What you get by building your own robot to fetch you beer or what ever you choose to do, is the satisfaction of knowing YOU DID IT.
The first computer program I wrote in Assembly was nothing more then moving a Player Missle Graphic around the screen using the joystick. (Atari 800) It wasn't even a game. But the first time that stupid (looking back) tie fighter moved on the screen so fast I couldn't tell what was happening. I about jumped for joy. After adding a loop which counted from 1 to 255, 255 times, figuring out that what I was seeing was in fact the graphic moving. There is a joy about building or making something work by yourself. That is what you get.
Lee
Artificer wrote:

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Artificer wrote:

Google 'BEAM robotics'. Since only masochists handcraft their own motors, you can't entirely dodge the issue of buying some off-the-shelf components. (IMHO)
However, one of the things that drew me to BEAM robotics years ago was the fact that, while you *could* purchase components, circuit boards, and entire 'bots off-the-shelf, people were generally encouraged to, and often did, draw some or most of their parts from 'techno-trash'- dead pc's, stereos, printers, vcrs, pagers, and the like. As for integrating you're programming accumen into the picture (if you're interested), I'll get back to you with a link on some interesting work someone did with using a PIC microcontroller emulate a BEAM microcore, and using the PIC's functionality to implement an experimental version of learning.
HTH, Tarkin
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