HOME >>
MAIN ELECTRONICS PAGE >>
ELECTRONICS "BASICS" PAGE
School, hobby electronics
This material is not 'polished'!!
As I surf the net, I come across various things that I wish someone had told me about. In theory, one day it will all be available in the polished sections of my website. In the meantime, if you're willing to 'dig' through some disorganized material, you may be rewarded with gems'!
School, hobby electronics.
This material is mostly about doing things with digital electronics. It goes back to the days of PICs and 6802 microprocessors, but some of the same material will be of use to modern (8/11!) readers using Arduinos, etc. There's not much here about how to add sound cards, hard drives, etc, to a PC. However, there is material on circuits you might want to build and connect to a PC via a parallel port, ISA bus, etc.
In some cases, the text is snipped from other sources. Therefore, among other things, the
personal pronoun may not refer to the editor of this page. If, on the
other hand something is identified as coming from 'TKB', he IS the pages's editor!
Material from earlier versions of this page has been 'polished' into more organized pages. Click here to visit them.
The page WAS in two sections... general stuff at the top, then notes about specific problems, projects, products on offer (e.g. digital i/o card) in second section. Unfortunately, it is a bit confused at the moment. I'll try to re-sort it in due course.
Click here for 'unpolished' material about using an MS-DOS / Windows computer's parallel port to control things or sense the 'outside world', or click here for 'polished' material.
Ad from page's editor: Yes.. I do enjoy compiling these things for you... hope they are helpful. However.. this doesn't pay my bills!!! If you
find this stuff useful, (and you run an MS-DOS or Windows PC) please visit my freeware and shareware page, Sheepdog Software(tm),
download something, and circulate it for me? Links on your page to
this page would also be appreciated!
Click here to visit editor's freeware, shareware page.
General Stuff
Q: Can some one tell me how to wire and the components needed for a
microcontroller that has the following: C or Basic interpreter,
LCD, keypad, temp sensor, and a serial port?
A:Try the Micromint PicStic:
in the US: http://www.micromint.com
(Supplier around since June 06, still present 8/11... PicStic may be long dead.)
In Canada: http://www.hvwtech.com
(Supplier around since June 06, still present 8/11... PicStic may be long dead.)
===
http://www.datalight.com MS-DOS compat OS in ROM, boot from pcmcia
or on board flash
(Supplier around since June 06, still present 8/11... Still selling ROM-DOS, also Linux, embedded flash OSs, etc.)
===
Another ROM-able Dos WAS at...
http://www.kila.com
... who 8/11 sell stethescopes.
===
You heard it here!... a long time ago! This entry left (8/11) just for fun. the old link no longer takes you to MSW Logo... I hope it still thrives somewhere... it was good!!
A group of Computing teachers in Western Australia have been
working on designing simple and inexpensive 'real world' interfaces
for use with MSW Logo (and other languages). It adds a whole new
dimension to using computers in schools. You can find details at
the URL below.
XXXX://www.southwest.com.au/~jfuller/mswlogo.html
===
8/11: Link no longer works...
Weather related science projects:
xxxx://www.erols.com/r.smith/weather.html#kits
they include:
computer controlled anemometer and thermometer (can be used for other
types of computer controlled measurements & counters)
lightning detector
cloud charge monitor
I will be adding projects for
photometer (measure light transmission in atmosphere)
seismometer
pocket microscope powerful enough to view living bacteria
===
Information/ web sites on science projects:
The Amateur Scientist section in the back of Scientific American
xxx://www.sciam.com/
8/11.. that takes you to...
http://www.scientificamerican.com/
(They did a couple of weather projects, for instance, possibly on web)
Popular Electronics Magazine
8/11: see
http://www.swtpc.com/mholley/PopularElectronics/Popular_Electronics.htm
for what was at xxxx://www.gernsback.com/noframe/pe/PEindex.html always has good stuff too.
8/11: http://www.swtp.com
There's a blast from the past! If you understand, you do, if you don't, I can't explain. Site today is "This site's purpose is to address the lack of technical information for some of the rarer vintage computers and related peripherals, with a strong focus on SWTPC."
Poptronix http://www.poptronix.com/ is (8/11) and was, as long ago as 6/06!,... also good.
===
Joshua Lang wrote:
Found an excellent site for oscilloscope information for beginners (like me)
http://www.tek.com/learning/
Was good 6/06, still good 8/11. URL tweaked.
Neil writes: I got one too.........If anybody else is looking for one, which
tests your reading ability of a oscilloscope screen which had me fooled at first,
it 's good and allows the student
to adjust the controls(Time,Trig,Slope etc.) It tests you up to using phase
angles in 3 easy to learn lessons. Neil
===
Q: Can anyone recommend a book to read that explains how to design and build your
own computer.. NO not from off the shelf components...
A: Are you more interested in doing the hardware or software?
FOLLOWING IS DATED. Advice at 8/11: Look at the Arduino. Old comment: If hardware, why not start with a more elegant processor, and a more manageable one? I've had great fun with the Motorola 6802. The TASM assembler (shareware) will let you program it from a PC. It will also allow you to program for other processors, so when you want to move on, you don't need to think about new tools. There have been many good articles in the hobbyist magazines which you can use as starting points and for guidance. If you can still get it, 'Introduction to 6800/6802 Microprocessor Systems', Simpson & Terrell, ISBN 0 408 01179 3 is excellent... maybe worth reading even if you decide to go with an Intel design... teaches assembly language programming as well as the hardware side. Also good, also 6802: 'Twenty Two Microcomputer Projects', D Metzger, ISBN 0-13-934712-7
FOLLOWING IS DATED. Advice at 8/11: Look at the Arduino. Old comment: On the other hand, if you're more interested in the software side, why not start with one of the Intel chip based industrial controllers... flash EEPROM based, I/O chips onboard. E.g. the things from Kila, out in Colorado. (AltaVista should be able to turn up a URL, let me know, or someone post one, please?)
FOLLOWING IS DATED. Advice at 8/11: Look at the Arduino. Old comment: Lastly, anyone with limited background in hardware and assembly language programming could do a lot worse than to do a few projects with microcontrollers, e.g. the Arizona Microchip PIC series, to build knowledge. Inexpensive... for about $20, I just bought a kit, including software & chips (but no 12v/5v psu... big deal), to build a board on which I'll be able to program (flash EEPROM) the little darling and then run my masterpiece. See the ads by Magenta,
REST OF THIS PAGE NOT REVISED (much) at 8/11)....
xxxx://ourworld.compuserve.com/homepages/Magenta_Electronics
(Note that's an underscore _ not a hyphen - ).. I went for their Kit 871.
8/11: http://www.magenta2000.co.uk/
Everyday With Practical Electronics magazine writes about PICs regularly
xxxx.epepmag.wimborne.co.uk
8/11: http://www.epemag3.com/
===
A web page open for anybody who might wish to contribute
to it any circuit diagrams, tips, useful info, etc.
if you would like to contribute something (and please do!), then email
me at kgor@usa.net
This web page is at
xxxx://www.pitt.edu/~olgst/electron.html
===
Also, some of the chip manufacturers on the Net have chip specs online
available to download. I just check National Semiconductor real quick but
didn't find your chips. (of course I only looked for about 30 seconds)
This URL may help you out
xxxx://www.online.ro/chipdir/chipdir.htm
8/11: Yes, Virginia, there was once a world without Google.
===
Someone asked: I'm looking at some data sheets, and there are
lines over some of the pin names. What does this mean?
Answer: The lines mean 'Not'.
For example, take an imaginary latch chip. It has data inputs
and a strobe input. To use the chip, you feed whatever data you
want to be latched into the chip into the data inputs, and when
the data is stable, you feed a pulse to the strobe input
(i.e., you make it go low then high... or maybe high then low...
both systems are used, the data sheet of a real chip will tell
you which one is in use in that chip.) Once you've done this,
the outputs will be whatever was on the inputs... until the
next strobe pulse, regardless of what happens to the inputs.
Let's also say that your latch chip has a further input called
'not chip enabled'. On the data sheet, this would probably be
a CE with a line over it. As long as that input is high, the
chip will ignore pulses arriving on the strobe line. ('Enabled'
can be used in many variations, by the way.)
The name of an input pin, e.g. 'not chip enabled', usually
reflects the state of affairs when that pin is high.
You'll also see output pin names with lines over them. Many flip
flops give you a Q and a /Q (which is a way of doing a line over
the Q if you haven't the typographic means). One is simply the
opposite of the other... when Q is 1, /Q is 0, when Q is 0 /Q is
1. They had a spare pin, and just took Q through an inverter.
You will find similar things at....
ele.htm
There 6/08. Still there 8/11! (Actually, there since before 6/98!)
===
Someone wrote: I am interested in learning about designing digital I/O devices for PC's
and I'm looking for resources which might include books, online
information, parts catalogs, newsgroups, etc.
I am not an engineer, but I do have a fair grasp of analog electrical
equipment, a programming background and experience with communications
DLL's. To start, I picked up a copy of Basic Digital Electronics at
Radio Shack and I'm making my way through this without too many problems
Get a copy of "The art of Electronics" by horowitz&hall
www.artofelectronics.com
There 6/06, and still there 8/11
It's not directly relevant (IIRC it has parallel port info, but that's it)
but it's a MUST HAVE for anyone involved in designing electronics.
"Interfacing to the IBM PC" is also good.
I'd love to be able to recommend cypress's $99 USB dev kit, but after over
2 months, I still have not received it. (I don't believe my CC has
been charged, but I'd like to have the goods)
See xxxx://www.mauve.demon.co.uk/ |Linux PDA, cheap electronics/PC bits sale.
See_header,_for_UCE_policy___________|_____________________________Ian_Stirling.
If it can't be expressed in figures, it is not science, it is opinion.
Robert A Heinlein.
Shhh I'm huntin Windows. --PRR
The book "Controlling the World with your PC" is a good place
to start. His examples work almost exclusively through the parallel
port, so they don't require building ISA/whatever cards.
+-------------------------------+------------------------------+--------+
| Jeff Francis - KC0BWS |"Clinton is a man who thinks | |
| Level Three Communications | 'International Affairs' | ____/| |
| Denver, CO USA DM79nr | means dating a girl from | \ o.O| |
| 39d43m16.4s N 104d52m10.7s W | out of town." | =(_)= |
| jfrancis@frii.com | -- Tom Clancy | U |
| http://www.frii.com/~jfrancis | on Larry King Live | PRR... |
+-------------------------------+------------------------------+--------+
===
Q: I have been searching for the answers for the following questions..but I guess they
are too easy that I can't find answers...
1. what's open collector
2. what's "pull-up" resistor is for, and how to use it, and determine the value
3. how to make a circuit at TTY voltage level? for example, if I use the Sharp
infra-red detector, and want to use the serial port to monitor the output,
what's a appropriate way to hook it up so that I won't fry the mother board?
A: You probably want to read the file named totmpole.tut on my TUTS/
(tutorials) subdir on my FTP Gateway from my website or FTP.
-Steve
--
-Steve Walz rstevew@armory.com ftp://ftp.armory.com:/pub/user/rstevew
-Electronics Site!! 1000 Files/50 Dirs!! http://www.armory.com/~rstevew
Europe:(Italy) http://ftp.cised.unina.it/pub/electronics/ftp.armory.com
===
Another answer: An "open collector" logic gate is when the final output transistor is
not connected to power internally. The advantage of this is simple, you
can then determine your output voltage and "internal" high resistance.
For example, you may want your output high to be 12 volts instead of
only 5.
A pull-up resistor is used whenever you want a "floating" line to be a
high. In an open collector circuit, it's used to connect your final
transistor to your pos voltage. It can also be used to keep a line high
until you intentionally put a low on it by a physical wire touch such as
in a lab setting. These are normally around 1 or 2 K, while a
"pulldown" has to be closer to 220 ohm.
===
Q: I've been trying to create some sort of device to detect light, and set an
alarm off when it does. This must be battery operated.
A: You might want to look at something like this
http://www.marktechopto.com/TOSHphototrans.htm
http://www.megsinet.com/bgriffey/docs/index.htm
===
Please come take a look at my robot website.....
it's cool i have a
robot message base
live robot chat room
an electronics forum
lots of robot related links
and a robot mailing list ( you can join when going to my website )
come now !! if you run a robot webpage e-mail me I'll link to your
website
and i just ask the same of you !!
http://www.morenorobotics.home.ml.org
===
Q: National Semiconductor has an internet site that has applications notes,
files use a .pdf extension. Does anyone know what kind of program it
takes to read these files?
A: They are encoded for the excellent, widely used Adobe Acrobat.
The good news is that Adobe have been clever (MSFT take note): you can have the excellent .pdf reader for free from
http://www.adobe.com/acrobat
(They SELL the program to encode files for .pdf)
===
Q: Where can I get specs for
PCI, SCSI, (E)IDE, EPP, Graphix chipsets, PS/2 SIMMs and DIMMs for RAM?
A: The FAQ's probably the best place to start looking for these - it's at
ftp://rtfm.mit.edu/pub/usenet/alt.comp.hardware.homebuilt/. Also for
chipsets, try the manufacturers (http://www.questlink.com/ is a good place if
you don't know who the manufacturers are to start with).
===
Q: Where can I find information about the programming of the floppy disk
controller?
A: I assume you want to talk to the hardware directly? If so, Try Intel... I
think the relevant datasheets are available from
http://developer.intel.com still. The original FDC chip is the NEC 765;
try a search or two for that one too.
Ralf Brown's interrupt list has some info, as does the book the
Undocumented PC. visit my site for the links & book info.
===
When someone asked about building his own ISA or PCI card, the
newsgroup community responded with the following advice...
Sources of ISA bus prototyping cards:
Jameco Electronics (www.jameco.com)(well behaved) and/ or
JDR Electronics (www.jdr.com)(graphics/cookie intensive)
A quick search of their on-line catalogs only turned up a blank
card with an ISA connector and bracket, but their printed catalogs
were said to have more variations, including a version with on-board
address decoding. This saves you the trouble of working out the
bus buffering and timing necessary to decode a particular input
or output address. You just build your circuit on the blank part
of the card, attach it to the data and handshaking lines from their
decoder circuit, set some jumpers or switches to tell their decoder
which addresses, interrupts, etc, you're interested in, write your
software to match, and off you go.
We've built several ISA bus cards for things like EPROM programmers
and the like, and after you figure it out once and build one or two
address decoders, it quickly loses its charm, so do yourself a favor
and spend the extra money for a card with a pre-built decoder section.
You (and your PC) will thank me. :-) You might want to take a look
at www.boondog.com - they have some tutorials and products that might
be just what you're looking for. Hope this helps!
bill_r@inetnebr.com
http://incolor.inetnebr.com/bill_r
(Good site with links and stuff about 'antique' machines, etc-tkb)
(Home of the COSMAC Elf Simulator!)
===
Q: I found this at
an instructional web site. It seems to contradict what I have already
learned. What do you think?
"Ceramic disk capacitors are often marked with a 3 digit code, that
simply tells the value in nanofarads. The first two numbers will be
the value, and the third will be the multiplier, similar to resistance
color codes. A 0.1 uF capacitor will be marked 103 (1.0 times ten to
the 3rd power nanofarads), and a 0.047 uF capacitor would be marked
472."
A: You said, in one of your postings, that the above is a direct quote.
That being the case, and the fact that this is an instructional web
site, you should email them and inform them of their error. Once they
reread the paragraph, they will see that it makes no sense.
When the followups confirmed that the passage was wrong, I did email
the keeper of the page - no response or change yet.
Generally the site seems helpful and has much correct information
and many useful links.
The paragraph should read:
"Ceramic disk capacitors are often marked with a 3 digit code, that
simply tells the value in picofarads. The first two numbers will be
the value, and the third will be the multiplier, similar to resistance
color codes. A 0.1 uF capacitor will be marked 104 (10 times ten to
the 4th power picofarads), and a 0.047 uF capacitor would be marked
473 (47 times ten to the 3rd power picofarads)."
You will also find, as you learn more about electronics and read more
books, that errors in electronic publications, are the rule, rather
than the exception. I have been reading electronic publications for
about 40 years now and have yet to find a book without errors. Some
where between the author and the consumer, something gets lost. Rely
on your logic. If it doesn't make sense, question it.
===
Do you want to learn how to interface your computer?
Check out http://ww2.sd.cybernex.net/~clevengr/lpt/ if you do.
===
Material from earlier versions of this page has been 'polished' into more organized pages. Click here to visit them.
Here is how you can contact this page's editor.
Link to 'My Desk Pile' main page
Link to another page of 'Desk Pile' electronics stuff