Lightning Detector
The Hobby Boards Lightning Detector allows you to count lightning strikes in your area
safely and inexpensively. This device can be mounted in a variety of ways – one
inexpensive and easy method is to place the device in an electrical conduit junction box,
with a length of PVC pipe protruding. The Lightning Detector fits neatly into the box,
and the length of pipe can be used to support the antenna.
The Lighting Detector uses a 9 volt battery, which should be connected to the battery
connector on the board. For safety, the portion of the circuit that detects lightning is opto-
isolated from the rest of the 1-Wire network. Thus this battery, rather than the 1-Wire
power line, is used to power the lightning side of the circuit.
IT IS CRITICAL that the Lightning Detector is connected to an earth ground. This is not
only for safety, but also to allow the Lightning Detector to work correctly. The earth
ground wire should be connected to the screw terminal marked EGND. For testing, it is
acceptable to use your house ground, but for a permanent installation we recommend
using a dedicated grounding rod for best protection and isolation.
The Lightning Detector must be connected to an antenna, using the screw terminal
connector marked ANT. A 14-gauge solid copper wire, 24” (60cm) antenna is provided
with the Lightning Detector. There are
no firm requirements for the antenna. If you chose not to use ours, you can easily make
one out of stranded or solid wire, insulated or not. We use 14-gauge solid copper wire,
but the gauge and material is not important since the current flowing through the antenna
is negligible. The length is also not critical. However, a longer antenna will be able to
detect lightning from further away. We typically recommend an antenna of around 24”
(60cm), but a 12” (30cm) antenna will work, and a longer one could be used if preferred.
The remainder of the installation is also very straightforward. To connect your Lightning
Detector to the 1-Wire network, you can simply plug a standard network cable into either
one of the RJ45 jacks. The second RJ45 connector acts as a pass-through, enabling you
to daisy-chain devices. Alternatively, you can use the screw terminals, connecting the
ground wire to the terminal marked DGND, and the data wire to the terminal marked DQ.
To test the Lightning Detector:
- Install the Lightning Detector on your 1-Wire network.
- NOTE that you must have an earth-ground connected during testing. The
lighting detector may not count without the earth-ground connected.
- This step requires the OneWireViewer from Dallas.
(We’re assuming you know how to use the 1-Wire viewer. If you do not, please see the instructions on
Dallas’s site.) Open the 1-Wire viewer, and select the DS2423 from the device
list. View the count on page 15.
- Using a utility lighter with an electronic spark, hold the lighter near the end of
your antenna, and spark it several times. The count shown on page 15 of the 1-
Wire viewer should mirror the number of times you create an electronic spark.
Please note that the lamp on the Lighting Detector board will not light during normal
operation. It is used to help dissipate energy from nearby lightning strikes if the circuit
gets a larger than normal power hit.
The Lightning Detector counts each static discharge from a lightning "strike". This means that when your eyes see a single bolt of lightning, the Lightning Detector is likely to detect multiple static discharges, so the count may be higher than you would expect.
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