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Is there any applet or something
that can read results and post them on the web site? (Max Kirilin)
Check Claudio Lanconelli's WebTherm at www.cs.unibo.it/~lanconel
or www.lancos.com
Why not the DS1820, that needs
only two wires? (Neil)
I
know the 1820, and I have discarded it because his strict time requirements
make it difficult to drive with a Visual Basic program. In addition to this,
and external drive as a mosfet is required for two wires operation. On the other
hand, the 1621 requires 4 wires instead of 2, but its interface is not very
time sensitive. Using the very same 4 wires for up to 8 sensors in parallel
sounds not so bad, tough. There are many worked examples of 1820 applications
on the net, try pointing at the Parallax's Basic Stamp world searching for "LOSA,
list of basic stamp applications".
Do you by any chance have an
english version of the SETUP software? (Micheal Korck)
Sorry,
no (note: the program can be customized editing the .INI file)
Why not the printer port?
Driving
the parallel port is more difficult from Visual Basic(*), while the serial port
is available through the mscomm control. Not to mention Windows NT difficulties
accessing hardware.
(*) there are
several DLL on the 'net, but I never tried one.
I have a Pentium 600, do I need
to add delay loops?
No,
forutnately VB and Windows are slow enough :-)
Can I use your sources with Visual
Basic 6?
Yes.
Where can I get the DS1621?
Europe:
www.distrelec.com --- USA and Canada:
www.newark.com (about $4 each)
Here in Finland it's really cold:-30
to - 40 °C. Is it possible to misure it with PC therm?(Juha Suuronen)
The
DS1621 is specified to work down to -55°C: I'm not as sure for the other components,
especially the 5V regulator. You can either search for the military specification
parts (hmmm, sounds hard to find), or use standard parts and checking
if it works at such low temperatures (cheap parts have large operating margins),
alternatively expose to low temp the DS1621 only.
When the computer is used heavily
in another task, say compiling a program, temperature misreads (seems to be
0 or -0,5)
This
is a known problem: I don't known the reason, but it seems like heavy loading
causes the serial port to miss events. I'm looking forward to a better explanation.
Can I add more sensors and call
the temperature(0) routine with a different id ie 0 to 7?
Yes,
the only problem could arise from power supply. Some serial ports can't supply
enough current to power all the sensor at once, so better to start with one
sensor attached than adding other sensors one at a time. Maybe you eventually
have to add an external 9V battery to help the voltage regulator.
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I can't find a 16 MHz AT90S1200.
Does this part really exist? I can't find
a 16 MHz AVR, can I overclock a 12 MHz part? Where can I
buy unpragrammed AVR parts? |
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When you say the AVR90S1200 is
cheap, how cheap is it?
My
quote (1998) was about 1.5 USD qty. 3000
Can I replace the MC34064P5 with
a MAX809 is a valid replacement for the MC34064P5?
Yes,
Choose an appropriate threshold (4,65 V or 4,40V). The higher, the better, even
if the chip can work below 4V.
Can I omit the reset chip? I've
seen schematics where RESET is tied to Vcc
The
main reason for reset circuitry is EEPROM data loss: when the power is switched
off, it takes some time before the voltage goes to zero. The chip can enter
an instable state when the supply is under its operating limits. The only way
to keep it stable is to keep RESET low, otherwise it can hurt itself starting
a spurious eeprom write cycle. Hagen Patzke tried successfully a transistor-based
reset from the Atmel web site.
I have "scaled down" your code
so it produces a stable display at 4Mhz ; it is essentially the same with
some tweaking and fiddles. (16Mhz parts seem to be scarce).
I wish to use this in a
project which will have PD source. Do you have any objection to this (you
will be credited for the video part of it, of course) (Paul Robson)
No
objections until the code remains public domain and you send me a copy of it
as a warrant that it is effectively available to the public. Click here to see
Paul Robson's code.
What programmer
do you use?
Only
the best one:SI-prog (www.artek.it) with free
Pony Prog prog software (www.lancos.com),
but Claudio is a friend of mine, so maybe I'm biased...
What is a SCART connector?
The
SCART connector (also known as PERITEL) is a standard connector on european
TV sets. This 21 pole connector provides: RGB input (best suited for consoles
and used to put images in color on my projects), videocomposite input and output,
audio input and output, plus a couple of inputs for real-time video source switching
(fast blanking on my projects) and slow video source switching (AV switch).
In case you don't have the SCART, you need either an RGB input connector or
an RGB to videocomposite converter to feed the VC input provided on most TV
and VCR. In both cases, some modifications on the original circuit are needed.
Do they work with NTSC tv sets?
No,
video designs are for 50 Hz field rate, 15625 Hz line rate. Please note that
these projects generate a non-interlaced video display, that is a display with
half the lines. I don't know of any porting of the video-dvm or bingo or crono
code to NTSC (60Hz), but I think it should be feasible.
Depending on your programming skill and previous video experience, you can put
your hands on the design and modify it. The point is to choose a suitable clock
frequency to adjust for exact line frequency. Then adjust the frame rate selecting
the appropriate line count.
I've got sync, but all charachters
appear as white blocks or do not display at all
Probably
you forgot to program eeprom data (reprogramming flash on AVRs automatically
erases eeprom data, so program flash first).
I want to mix broadcast video
and text for use as a display in a home automation controller (Peter Williams)
You
need to sync to incoming signal. Look here for a worked example. Check here
also.
How does PAL works? How can I
get PAL output?
As
regards the PAL basics, I found that the video generator project published on
www.picpoint.com is very well documented
(and describes a simple circuit to make a video composite signal from RGB components)
Do the video projects work without
a SCART?
Video-DVM will work, the others I fear not. They use the Fast Blanking
(pixelwise) input of the SCART to switch between the black&white signal
(from the composite input) to the R-G-B signals.
Can I modify the code to make
a clock?
Yes, check also http://www.brouhaha.com/~eric/pic/pictock.html
to see a worked solution.
Did you ever think about an midi-data
monitor that displays the names of the received midi-bytes (note-on/note of,
program change and so on) on a TV, would be a great help-gadget for musicians......There
are computer-programs for this goal, but there is always a big computer needed.......if
you like this idea, you may use the idea for free. But if you really publish
such a project please name me as the bringer of the idea. (Gert Bouland, The
Netherlands)
Anyone wants to put his teeth on the idea?
Do you know what carrier frequency
does all remote controls have ? What >IR-Decoder should I buy? 36, 38, 40kHz
?
In Europe, RC5 encoding is used by Philips and many other brands,
and uses 36kHz.
Is there a code how to sample
a remote control signal?
Check the Tomi Engdahl's pages for encoding description, and Claudio
Lanconelli's pages for sample code using his "minithreads"system.
I want to do Irda. Where can I
find info & parts?
Lots of info can be found at www.irda.org
; the RS-components catalog shows some IRDA modules. (try www.rs-components.com)
Did You ever tried to built an
interface to let the cfx act as a terminal ? (Thomas Nabfert)
Some time ago I saw a program that claimed to work as a "terminal"
using two CFXs. Now it has disappeared. I can't figure how it worked, because
as far as I know, the "Send(X)" instruction on the Casio does not work
as expected (i.e., symmetrically to the Receive(X) ).
I don't know the PIC16C84 - is
it able to handle two serial ports ? In this case the PIC could act as an
Protocol-interface between the cfx and >a VT100-device. (Thomas Nabfert)
There
is enough horsepower in a PIC to handle a second serial port in software, provided
you don't need too large a buffer. Just in case, the XTAL frequency can be increased
to 10 MHz instead of actual 4MHz.
Can I get negative temperatures
out of an LM35?
The
LM35 gives negative temperatures in the form of negative voltages (relative
to ground pin). You can change the software to operate the AD converter in bipolar
mode, but it's probably easier to add a positive offset to the GND pin so that
it reads as positive at 0 degrees. You don't need a very stable voltage: in
fact you can use another AD input to measure the amount of offset and then subtract
it in software from the temperature read. Check National's datasheet for details,
they usually give good application notes.
What Maxim part should be used?
Digi-Key list two different chips,Max186bcpp with ref and Max186dcpp with
v ref. (Albert Hance)
If
I interpret correctly the Maxim data sheets, the letter following the 186 is
the component selection (from A the better to D the worst). Then "C" means "commercial"
temperature range (0-70 deg. C), and PP = dil plastic package. I'm not sure
to understand what with ref and with v ref means.
How much does a Casio calculator
cost?
From
Bob Weir (Colorado, USA): The local Wal-Mart is selling the 9850 for $60. and
that includes a rebate coupon good for another $20 (1999).
How much do the chips cost?
You
should be able to get both chips for less than $15 (retail, 1999).
Cannot read the LCD pictures from
PDF file
The
pictures of the LCD screen from the .PDF file can be fuzzy: here is a clearer
version (Note: the LCD sample has been removed from the html version)
What type/brand of ultrasonic
transducers you used and approximate price.( Bobby Echevarria, Manila, Philippines)
I
got the parts from the German MONACOR catalogue, I'm unable to supply a part
number but these kind of piezos were quite popular at the time. Nowadays, the
are widely used on car burglar alarms. Any TX-RX couple working at 40 kHz should
do the job.
Strange pinout for 7808 voltage
regulator ( Bobby Echevarria, Manila, Philippines)
You
are right, the schematic is drawn with Protel that uses such a misleading pin
numbering.
Is an assembly scheme available?
No
(gone with the car).
Where do those pin go?
Pin list:
Suggestion for
overlaying text on existing video
You
can get , 25 rows by 40 columns color text display with block graphics using
the EXISTING teletext circuitry on the tv set.
Most of the actual tv sets
use ICs compatible to the Philips/Siemens standard. They have an IIC bus and
writing characters to the tv screen is a matter of bringing out the bus (two
wires and ground, a simple jack plug can do) and issuing IIC commands from the
PC. I've tried this several years ago on an ordinary tv and it worked.
Maybe the simple IIC interface used in my pcTherm design is capable to drive
your tv. It is then a matter of issuing the right IIC commnad from the PC
If
you don't want to touch the TV, then you can use the same chip that is inside
the tv to build an external board! It produces RGB signals that can be brought
to the SCART connector. These teletext chips are usually found on surplus teletext
boards or as spare parts.
Assembler generates errors
The
AVR code of Bingo, Chrono and Video-DVM was assembled using one of the early
versions of AVRASM. I'm doing guesswork, but I think newer versions include
(as embedded pseudo-commands) the macros I had to include in earlier versions.
Try eliminating them or - just to be sure not to introduce errors due to slightly
different implementations - renaming them eg. skipne -> myskipne (be sure to
rename ALL occurences of the macro). This problem is not a concern if you don't
need to modify the software, as AVR the executables are supplied as well.
I cant find the MM53200 data sheet!
The
chip was made by National but it is now obsolete, so they don't have any info
on their site :-(
If you can read italian, try this link: http://www.freeweb.org/hobby/i2viu/rx53200.htm
Net english anymore?
I
don't have any URLs about net-english, it is just a name to figure out an idea!
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PC-therm questions