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.
2008-08-12 (#)
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.
2008-08-10 (#)
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.
2008-08-04 (#)
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.
2008-07-28 (#)
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.
2008-01-07 (#)
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.
2008-01-02 (#)
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.
2007-12-21 (#)
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.
2007-12-20 (#)
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.