1-Wire Sensors

The 1-Wire Lightning Sensor

1-Wire Lightning Detector open box
1-Wire Lightning Detector mounted

A small project that works great!

This is the 1-Wire Lightning Sensor sold by Hobby Boards. This sensor listens for the distinct radio signals a bolt of lightning creates. If you are old like me, you will remember holding a transistor radio as a storm approaches, you would hear static every time lightning flashes. Well, this sensor listens to that station.

1-Wire is NOT a company. 1-Wire is a protocol developed by Dallas Semiconductor that allows you to easily connect up to 100 sensors using a single run of CAT5 (Ethernet) or RJ11 (Telephone) cable. I like to use CAT5 as the shielding is better on these cables. Sensors have 2 RJ45 (Ethernet) connectors built onto the circuit board. You simply daisy chain these sensors to each other, up to 100 of them, up to 900 feet of cable.

You can build your own 1-Wire sensor. There are directions for making just about any sensor you like online. Simply Google "1-wire sensor type". Obviously type the type of sensor your interested in building...not the actual words "sensor type". You should get many plans to choose from.

I am a computer geek, not an electrician or electrical engineer. If you are more like me than MacGyver, you probably like your circuit boards already made. That's where the company Hobby Boards comes in. They make the circuit boards for you, you just add the housing, the Cat5 cable and in this case, an antenna.

I decided to use an outdoor power outlet box for housing this circuit board. You can use whatever you like, but you have to use something that will protect the circuit board from rain. The box I purchased was $14.00 at Ace Hardware. I used 2 computer motherboard stand-offs to mount the circuit board to the back plate of the box. I then sealed the back plate with silicone to avoid moisture getting to the board from behind. I purchased a 39" telescoping radio antenna on Amazon.com for $10.00. The circuit board cost me $33.00. I mounted it in the box, wired it up to the board, and I had me a lightning detector! For under $60.00 you too could have lightning detection.

The pictures above show the sensor before I mounted it outside, with the box I used as a housing. The box is shown open so you can see the circuit board and wiring. The second picture I show the sensor after I mounted it. The black wire you see in the open box is the wire Hobby Boards sent with the sensor with the intention of me using the wire for an Antenna. I used a short piece of this wire to run from the circuit board to the antenna I actually used. I used the rest of this wire to run to ground. The better the ground, the better it will work, and the fewer "false strikes" the sensor will detect. I used an 8 ft copper grounding rod pounded into the ground till just an inch or so was exposed. I used electrical tape around the base of the antenna to snug it up in the hole I drilled in the side of the box. I then used glue to seal things up. If you look close at the mounted unit, you will see that I used a small piece of wood and a cable tie to add support to the 39" antenna.

If this is your first 1-Wire sensor, there are other costs involved. There is a USB or Serial 1-Wire adapter you have to purchase or make so your computer can talk to the sensor. There is the CAT5 cable you need to have/make/buy. You also need A CAT5 (Ethernet) TO RJ12 (telephone cable) adapter that you need to make or buy. The USB adapter I purchased uses a RJ12 connector. All the sensors I bought use RJ45 connectors...Why? I have no idea, that's just what they use. You can purchase a converter cable or make one like I did. The wiring is very easy and listed on the Hobby Boards site as is the free download of the software drivers for the adapter.

The 1-Wire Lightning Sensor is supported by the Weather Display software, so it is a pretty easy "add-on" to your existing weather station.

For me, this is a really useful sensor. So far, I have not seen any false "strikes" out of this sensor. It has been online 6 months or so when I wrote this, so if it does false, it is not very often. When it first starts indicating that lightning is in the area, I have had about an hour and a half till the storm actually hits. To me, this is extremely useful information. The software Weather Display sounds a very loud thunder sound when the sensor detects lightning. That too is useful.

I have a link to Hobby Boards in the Weather Candy section of this site. So if you decide to add one of these to your weather station, give these guys a look for a built board or for parts to make your own.

The Acu-Rite 5-in-1

The 1-Wire Solar Radiation Sensor

1-Wire Solar Sensor unmounted
1-Wire Solar Sensor mounted

Another small project that works great!

This is the 1-Wire Solar Sensor sold by Hobby Boards. This sensor detects the intensity of the sunlight. It detects the highest amount of solar radiation in the summer between noon and 2:00PM. If the gauge goes much over 1000 on any given day, this simply means I have it calibrated wrong and I need to make an adjustment. The red shaded area that moves in a V shape towards the center of the gauge is the max sunlight possible for this day and time. Ideally on a sunny day the gauge should be riding the lower edge of this shaded area. If I am above the upper edge of that area, I am definitely calibrated wrong. As long as I am inside the red or below it, I figure I am close to right. This is after all "the unofficial weather" and I am not spending $10,000.00 to get a sensor that will be calibrated to tell you precisely how sunny it is outside. The sensor cost $30.00 and it is close.

If you read the description of the Lightning sensor above, you get some information on 1-wire sensors. I am going to assume you have read the above description and not repeat myself. :-)

The first picture above show the sensor before I mounted it outside. I ordered the box Hobby Boards sells to house this sensor. The box is NOT weather proof. In the second photo, you see that I housed this box inside a Rubbermaid container to provide weather proofing. Unfortunately, a Rubbermaid container reflects the radiation I am trying to detect, so I had to cut a hole over the solar sensor and rig up some weather protection for the hole. I believe it will protect this sensor from a strong storm.

The 1-Wire Solar Sensor is supported by the Weather Display software, but what I thought was going to be an easy install turned into a several day project with lots of hair pulling. The sensor hookup was easy; the Weather Display software setup was not so much.

First, a Weather Display "gotcha" is that you need to enter Latitude and Longitude. If you are in the USA, like me, Longitude is a negative number, minus something. Well, Weather display wants you to enter it in a positive number. If you enter it wrong, it will turn off your sensor in the morning and turn it on at night. UGH...

Second Weather Display gotcha is calibration. You need to enter the maximum mv the sensor gives off, so the solar intensity can be calculated. Problem is, there is nothing I could find, anywhere, that gave me a clue as to what this number should be. My first solar reading was 27,595 Watts per meter squared. This should not be above 1000 watts per meter squared. So my sensor was basically telling me I was installed the surface of the sun while holding a billion candle power flashlight on my sensor. Needless to say, this reading was wrong. I have narrowed the mv that Weather Display needs, for my sensor, where I have my sensor mounted is 75.9 mv. I will probably end up tweaking this number some in the future, but it is pretty close to correct. Summer sun at its peak on a typical clear day reads about 985 to 995 Watts per meter squared... maybe 1025 on a REALLY sunny day. It can go higher, but it is very unusual. So if you are reading much above 1000, you probably need an adjustment. If you setup this sensor, your setting will probably differ from mine, but at least you have a starting point to figure out how to calibrate it.

Why do I care what the solar radiation is outside? The answer is: you probably don't. Solar radiation is good indicator of "the sun is up" and "it is dark outside". Other than that, it is a mere curiosity of if you need sunglasses or not. Over 800, it is really bright outside. Wear your shades. If it is under 10, it is really cloudy outside... or it is becoming night... or a squirrel has decided the sensor mount is a really neat spot to sit... I have found it useful for my Weather Radio. If it is sunny, Dotty and Stephen (The animated radio voices) talk about sun glasses and such. If it is noon and low sunlight, they can crab about it being cloudy.

Solar radiation has no direct relation to the UV index except when Solar Radiation is high, the UV index is probably high too. Unfortunately, I can't find anyone who makes a UV sensor right now. So we will have to settle for solar radiation only.

I have a link to Hobby Boards in the Helpful Links section of this site. So if you decide to add one of these to your weather station, give these guys a look for a built board or for parts to make your own.

The Acu-Rite 5-in-1