News items for tag onewire - Koos van den Hout

A night with a heavy thunderstorm and high numbers of lightning strikes detected. No local damage, we just saw hailstones come down, break up and the parts still fly around for over a meter. So we were glad we weren't outside at that time.

In following some links about 1-wire projects I found a German Supplier of 1-wire components which can be interesting: Fuchs Elektronik sells 1-wire components at a reasonable price such as the DS18B20 1-wire high resolution thermometer. Too bad they don't sell other interesting sensors like the barometer which could help in combining an order.

During all the work in the house some of the 1-wire temperature sensors were disabled and removed to avoid damage. Today I did some work on the house and re-installed them. The sensor in the living room is now installed inside the room thermostat so it's hidden and should give the same reading as the thermostat. I also re-installed the temperature sensor in the crawlspace which will show up in the sensors at home overview.

The temperature sensor connected to the heater is working nicely and tells us the problem with the heater is only in the hot-water producing part.
And the picture is a nice update for the 1-wire projects page.

Our heating seems to be having problem, probably related to the changes recently. But to diagnose the problem completely we need to see what is happening. So one of the one-wire temperature sensors is now tie-wrapped to the output pipe of the central heating and measurements are logged.

When I bought some 1-wire sensors a while ago at Hobby boards I included the lightning detector in the order. I installed it indoors in the attic where it also counts the switch of the fluorescent lights, so it will probably work better in an outdoor weather station further away from interference. But, in the early hours of today there was a heavy thunderstorm over this country and it counted like crazy. The stated sensitivity is about 80 kilometers:

this lightning detector will be able to pick up lightning more than 50 miles away

With the 75000 lightning strikes reported in the Netherlands for that night, the numbers don't look that strange.

When the heating started working for winter I noticed that the crawl space temperature was going up in the same patterns as the living room temperature. It looked like the whole crawl space was heated. I already wondered about the relation between crawl space temperature and heating up the room back in September. So the results are in: Not really necessary and costing us money. I looked in the crawl space and noticed that there is a really long set of heating pipes from the back of the house to the front (over 8 meters long). This has to do with the old design: the first central heating was in the shed in the garden. The long pipes pass within a meter of the temperature sensor. So I put pipe isolation on the long run, now to check the graphs for improvement.

The replacement 1-wire interface arrived and the 1-wire network at home is working again. I also added a few temperature sensors so the assorted sensors at home now also show the crawl space temperature. Yes, I crawled under the house and hung a temperature sensor from the underside of the floor, connected to the 1-wire network. Correlating the temperatures over longer time with the weather can give me an insight whether underfloor isolation and heating pipe isolation will have a lot of influence on our heating bill.

In browsing other 1-wire resources I found this gem: a snow depth sensor. The page reports of the development and improvements in the measuring of snow depth in Voksenlia, Norway. A place where measuring snow depth is worth it, the local record is over 200 cm of snow. The result of loads of precipitation: over 1000 mm annually.

I took some time to work on the house 1-wire network today.. and blew up the serial to 1-wire interface in the process. I think there is a voltage difference between house ground (water pipes) and 1-wire ground and I touched a metal part of the 1-wire counter I was going to use for the electricity counting to a water pipe hiding behind another pipe when I was trying to test whether it responded to the led in the electricity meter. So, still no success on measuring electricity and no new house temperature readings either. I did put in an extension of the 1-wire network from the attic to the cupboard beneath the stairs where the electricity meter lives. I used the 'isdn' sockets on the end of the long 1-wire connection so as a side-effect I moved one temperature sensor from the top of the server to the 'wine rack' area and updated the sensors page. It is a different location temperature-wise so I started new statistics for this sensor. I also looked at options for placing a temperature sensor in the living room. The cable to the thermostat is thoroughly cemented in so I can't place a wire alongside that cable. I'll probably use the hole for an extra television-coax cable to get a wire for a temperature sensor from the crawlspace to the living room. I already ordered a replacement serial 1-wire interface. I hope that is the only component that was damaged.

Finally I counted a few light pulses with the one-wire counter. No big circuit with the Velleman MK120R kit but just a photodiode and a resistor hooked up to the counter module. I got the idea from looking at the schematics for the Hobby Boards 1-Wire Lightning Detector. The counting circuit is a phototransistor (in an optocoupler) and a resistor. With a bit of tweaking on the resistor I eventually got the counting circuit to count 2 light flashes from a flashlight. With some more tweaking of the resistor value I think I could count red flashes from the electricity meter.

I also installed the lightning detector under the roof. But it is too close to the wiring of the house I think: sofar all counts are related to me being in the attic and turning on the light. In a 'real' setup I think it needs to be away from the house. Something to keep in mind for the project sundial weather station.

No local source for a photodiode which is sensitive to visible light. Time to shop on-line for a photodiode which is sensitive to red light, which will be listed as 650 nm, is directional and can deal with the amount of red light from the electricity meter LED. Reading specsheets for photodiodes is also new to me. I found a webpage with lots of explanations about LEDs and calculations. But, ordering a component on-line which costs less than a euro is a bit silly, with probably a lot more costs in shipping and handling. Conrad just charges extra for too small orders.

I finished soldering the Velleman MK120 receiver I will use for detecting the lightpulses from the electricity meter for the one wire electricity measuring project. I think that is the first soldering of a circuit board since somewhere around my electronics education which finished in 1989 and I did it right! The circuit works as designed: it needs a strong infrared signal to not send out a signal via led and buzzer. I did not solder the buzzer because eventually the signal needs to go into the 1-wire counter and buzzing sounds from the cupboard under the stairs might get irritating fast. After checking whether the circuit board worked as designed I swapped the inputs on the comparator like in the 1-wire electricity monitoring design by Jon00. I did not cut traces and solder wires, I used the IC holder to set up 2 crossed wires to the pins of the IC.

In testing I found that the L-53P3C photodiode is very good at receiving infrared, but the red led in our electricity meter does not emit enough infrared light to trigger the circuit. I think I'll need to find a different photodiode which is more sensitive for visible (or just red) light.

My 1-wire projects also got their own page. And I ordered the parts for the new project. And a few other bits, including more temperature sensors. So, with some soldering time I'll be monitoring electricity usage soon.

I decided to start monitoring the electricity usage in the house. Using 1-wire sounds the most logical to me as I am already using that to monitor temperatures. I found a description by Jon00 using a MK120 Velleman Kit which sounds quite compatible with my level of electronics knowledge and my budget. So I went to the local electronics shop, Radio Centrum and bought the Velleman MK120. I asked about a 1-wire counter but they don't sell 1-wire equipment (yet?). Well, a counter is something I can order from Hobby boards. Probably together with some other 1-wire stuff to make it an interesting order.

Yesterday I found some time to install the new 1-wire sensors in a place where I am interested in the temperatures: the attic where the home server gosper lives and started fetching data into rrdtool databases. The assorted sensors at home page now shows some of the available temperatures. Sensor 2 lies in the open area right below the top of the roof.

The 1-wire sensors and adaptor I ordered arrived today and I started playing with DigiTemp. After running into a faq item (make sure you don't have crossed phone cable) it started working like a charm. The DS18S20 sensors work really easy and they are quite precise and fast to react to temperature changes such as touching fingers. Two sensors in the home office: on a switched-on PC speaker Sensor 1 C: 19.38, on another speaker switched-off Sensor 0 C: 18.81.

Some environment sensors at home are now public. Started with the environment sensors of the home server gosper which are the easiest. Other stuff will be added if and when certain monitoring projects go from being a wild idea to delivering real data. Ok, I did order some temperature sensors and a 1-wire controller from Hobby Boards 1-wire solutions.

At work I "took over" a fourfold temperature sensor, Quozl's Temperature Sensor. It got me interested in the 1-wire system for sensors. Applications like Thermd and DigiTemp make it possible to log all kinds of environmental data easily. I'm seriously considering getting a simple 1-wire interface for the server at home so I can monitor several inside temperatures (the cheapest to monitor and the most interesting to me) by just stringing some cheap phone wires and hook up sensors. Yet another network, although this one would be simpler to maintain.