C
cessna
Guest
Looking to build one to detect incoming traffic, like the traffic
signals have.
Any ideas to keep this simple?
signals have.
Any ideas to keep this simple?
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R
Richard Crowley
Guest
"cessna" wrote ...
A medium-to small yappy dog with a view of the driveway?Looking to build one to detect incoming traffic, like the traffic
signals have.
Any ideas to keep this simple?
H
Harry Conover
Guest
cessna <NFroehling@houston.rr.com> wrote in message news:<z_qWb.4507$vz1.1327@fe2.texas.rr.com>...
a detector loop embedded in your driveway. The electronics of these
are simple, but installion of the loop in the driveway is a real
bitch, plus could end up damaging your driveway!
Were it me, I'd simply purchase a simple weatherproof ultrasonic or
r.f. based proximity detector switch and mount it next to the
driveway. Check what's available to control outdoor lighting at Home
Depot or Lowes.
Harry C.
You could try the same method that's used to control traffic signals,Looking to build one to detect incoming traffic, like the traffic
signals have.
Any ideas to keep this simple?
a detector loop embedded in your driveway. The electronics of these
are simple, but installion of the loop in the driveway is a real
bitch, plus could end up damaging your driveway!
Were it me, I'd simply purchase a simple weatherproof ultrasonic or
r.f. based proximity detector switch and mount it next to the
driveway. Check what's available to control outdoor lighting at Home
Depot or Lowes.
Harry C.
C
cessna
Guest
The loop is no problem here, I haven't laid the concrete, but that is
the next step, how many turns would be used? and what is the circuit
like? any schematic?
Harry Conover wrote:
the next step, how many turns would be used? and what is the circuit
like? any schematic?
Harry Conover wrote:
cessna <NFroehling@houston.rr.com> wrote in message news:<z_qWb.4507$vz1.1327@fe2.texas.rr.com>...
Looking to build one to detect incoming traffic, like the traffic
signals have.
Any ideas to keep this simple?
You could try the same method that's used to control traffic signals,
a detector loop embedded in your driveway. The electronics of these
are simple, but installion of the loop in the driveway is a real
bitch, plus could end up damaging your driveway!
Were it me, I'd simply purchase a simple weatherproof ultrasonic or
r.f. based proximity detector switch and mount it next to the
driveway. Check what's available to control outdoor lighting at Home
Depot or Lowes.
Harry C.
R
Richard Crowley
Guest
"cessna" wrote ...Harry Conover wrote:
You could try the same method that's used to control traffic signals,
a detector loop embedded in your driveway. The electronics of these
are simple, but installion of the loop in the driveway is a real
bitch, plus could end up damaging your driveway!
I'd embed a "hula hoop" (circular plastic tube, popular toy from theThe loop is no problem here, I haven't laid the concrete, but that is
the next step, how many turns would be used? and what is the circuit
like? any schematic?
1960s) with an access box and a plastic conduit to the edge of the
driveway. Reason: All the loops I've seen have been re-installed
more than once (not sure why). Either make it "re-enterable" or
be prepared to have it quit operating at some point without any
possibility of repair.
The professionals install these with a gigantic "hole saw" on the
bottom of a truck. The diamond tips cut a large (2-3 foot) diameter
circular slot into which several turns of wire are laid. Then the
slot is sealed back up (with epoxy or such?)
The circuit is almost certainly just an oscillator that uses the
large loop (inductor) as part of the frequency-determining
LC tank. Same principal as any other metal detector (like the
ones used for detecting nails/studs in your walls, etc.)
H
Harry Conover
Guest
cessna <NFroehling@houston.rr.com> wrote in message news:<nlzWb.7985$vz1.7471@fe2.texas.rr.com>...
IIRC 4 to 8, usually in the shape of a rectangle (or more recently a
diamond shape, presumably to enhance the detection of motorcycles).
I've never measured one, but they're roughly 3x6 feet in size. (Try a
Google search on 'traffic loops'.)
These urls may be helpful:
http://www.microconsultants.com/tips/loops.htm
http://www.hardingsystems.com/traffic/loops.htm
http://draco.acs.uci.edu/rbfaq/FAQ/8i.2.html
http://raiproducts.com/proseal_ex.cfm
One type detector consists of an LC oscillator with the loop
functioning as the inductive component. This is combined with an
active notch filter and a detector circuit driving a relay.
I've never built one of the loops, but I'd begin by driving 4 nails in
a sheet of plywood to define the sized and shape of the loop. Then
wind it with 8 turns of #16 wire going around the nail rectangle and
test it with the detector electronics for resonant frequency and
sensitivity.
Once it works to my safisfaction, I'd solder its leads to end of a
length of #12 UF-B to connect with the detector, coating the entire
assembly with multiple coats of RTV silicon rubber potting compound.
To embed it into the concrete, you can support it it position with
four small stakes before the pour.
I would caution you that both rebar and steel mesh (often used to
reinforce concrete) could pose a problem for the loop, but I have no
idea to what extent.
Harry C.
The traffic loops I've seen in use consist of a relatively few turns,The loop is no problem here, I haven't laid the concrete, but that is
the next step, how many turns would be used? and what is the circuit
like? any schematic?
IIRC 4 to 8, usually in the shape of a rectangle (or more recently a
diamond shape, presumably to enhance the detection of motorcycles).
I've never measured one, but they're roughly 3x6 feet in size. (Try a
Google search on 'traffic loops'.)
These urls may be helpful:
http://www.microconsultants.com/tips/loops.htm
http://www.hardingsystems.com/traffic/loops.htm
http://draco.acs.uci.edu/rbfaq/FAQ/8i.2.html
http://raiproducts.com/proseal_ex.cfm
One type detector consists of an LC oscillator with the loop
functioning as the inductive component. This is combined with an
active notch filter and a detector circuit driving a relay.
I've never built one of the loops, but I'd begin by driving 4 nails in
a sheet of plywood to define the sized and shape of the loop. Then
wind it with 8 turns of #16 wire going around the nail rectangle and
test it with the detector electronics for resonant frequency and
sensitivity.
Once it works to my safisfaction, I'd solder its leads to end of a
length of #12 UF-B to connect with the detector, coating the entire
assembly with multiple coats of RTV silicon rubber potting compound.
To embed it into the concrete, you can support it it position with
four small stakes before the pour.
I would caution you that both rebar and steel mesh (often used to
reinforce concrete) could pose a problem for the loop, but I have no
idea to what extent.
Harry C.