Using PIC Processor to
I am an old time subscriber of NV
and am looking for info to use PICs to
generate DTMF. I am using a PIC
18F2431. Can anyone help? Any
assembly code would be of great help.
#4101 Mitch Esken
Car Autoranging Ammeter
Looking for a circuit for an
autoranging car ammeter. In-line cable
shunt output at the battery. Resistor
short protection at the battery for a
pair of sense wires running to the
circuit and meter under the dash. Car
battery powered, no microprocessors,
low range 0 to 10 amps, high engine
start range for starting current,
d’Arsonval meter, not digital. Want to
see relatively fast amperage changes.
Should this go in the negative or
positive side of the battery? Accuracy
on 0-10 amp range say 10% or better.
20% or better on the engine start
Costa Mesa, CA
78 April 2010
We have four indoor/outdoor
cats. My plan is to have each of them
implanted with an RFID chip and to
have a sensor over the cat door which
will read them. The door is already
wired to indicate "a cat has gone in" or
"a cat has gone out." Now I want to
know which cat, and also possibly
have the cat door remain locked until
a known cat approaches.
I purchased an RFID reader module from Parallax and although this
worked okay with the tags supplied,
there was no response from the RFID
chip borrowed from our friendly vet.
Does anybody have a suggestion
for (a) what type of RFID chip to
use (there are more than one); and
(b) where I can obtain a bare-bones
scanner. I want to capture the tag ID
using my own microprocessor when a
cat is in range of the sensor.
I would like to put together a
flame sensor using flame rectification.
I am familiar with how it works however, I need some ideas for the sensing
electronics. The furnace I have uses a
hot surface ignitor.
I am building a Steampunk
keyboard for my own use. I would like
to have a small motor spin some gears
each time a key is pressed on the
computer keyboard. I have not been
able to locate an encoder output or an
activity monitor that will show key
presses. I don't care which keys are
being pressed, and the gears spinning
are just for show. I would like a hardware solution over a software solution
— but a complete *.exe program
would be acceptable. (Maybe flashing
the scroll lock LED when keyboard
activity is being transmitted to the keyboard controller.) Monitoring the data
stream for F0(Key up) occurrences
would also work.
I'm trying to build a simple RF
detector that flashes an LED when it
detects a cell phone signal, as well as
Wi-Fi. I’m trying to keep it simple to
keep costs down. I assume it would be
All questions AND answers are submitted
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easiest to use an amplifier, but I’m trying to get a PIC for the detection. The
most trouble I am having is on the RF
section. Finding the right antenna has
been difficult. Ive tried using different
wire lengths with some detector
diodes, but have been having no luck.
Machine Motor Controller
In some semi-automatic
machines, there is a controller which
controls the forward and reverse
direction of the motor. The controller
is driven by a small motor and gear
arrangement with three options: light,
normal, and heavy wash.
Please suggest a simple electronic
replacement circuit for the same.
#4107 Ajay Kumar Verma
Pulse Welding Circuit
I have a transformer type AC/DC
TIG welder I would like to add pulsing
to the output. Does anybody out there
have a circuit diagram so I could add
PIC Micro and USB
Long ago, I was competent
programming in Microsoft QBasic.
Now most/all articles use either
assembly or C. Do any of the popular
microcontrollers program in some version of Basic? I am not into a "C" level
of retraining at age 67. Suggestions ...
I’m looking for serious how-to
articles — or worst case — books
on using some microcontroller that
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