Weather station update!

It has been quite a while since I last posted here, it was a busy year! I became a father, and that took a lot of the time available to report - I still get quite some time to do the things, only no time to spend here reporting :) , but I hope to revive it now!

So here is an update on the weather station!

Finally, after 11 and a half months the thing died! in the coldest night of the year, after sending a packet indicating -8.1C outside at 3 in the morning...

funnily enough, the FS20 switch that turns the boiler on and off died (stopped receiving) at approximately the same time...can't explain it, it wasn't cold in the room where that one is located...

It sent 51273 messages on a set of 3AA GP branded units, which were not new when it was put outside. Since for each packet I measured the wind for 1 second, this means the JeeNode was in full power mode for a bit over 14 hours.

Anyway, I opened it, days later, and when the temperature outside was up to -1 and the batteries read about 1.9V, or about 0.6V per cell.

I wonder if the fact that the Atmega runs at 16MHz, which is out of the specs at 3.3V (let alone 1.9V), contributed to it failing at low temperature/very low voltage as well, or if it could have been pushed any harder! It is out now with a new set of batteries, since 8/12/2010, but I need to redo the anemometer, so I don't think these batteries will be out until they die!

I think this was a victory for a JeeNode in low power mode!

As for the FS20 switch, I still do not know what happened...It just would not receive, until I moved it to a different place, where reception is fine. I wonder if all the snow on the roof created some effect, which prevented it from working properly. Maybe i should try now that the snow melted. However, if that is the case, then I definitely can not leave it there, as it is precisely when it is cold and snowy outside that I need it the most!
Plans are on the making anyway for a JeeNode OpenThem controler, which should be comming soon. I already developed the control loop (PI) which determines the desired water temperature, now I just need to adjust the PI coeficients and implement the hardware, for which most components are already in the house!

I hope to report before the new year again on another project!

Tektronics 453

Just got an old Tektronics 453 Oscilloscope that was going to go in the garbage!! Looks great and it works! which is the most important part! now I can finally check the hall effect sensor I got in Taiwan when near the water meter to see if I can detect the parts rotating inside the meter. At this moment the signal is smaller than what the Arduino can detect, and I would like to see the signal before starting to build an amplifier - also to know how much amplification does it need!


It came with 2 probes, nice old ones, one from Phillips and one from Tektronics! I think there are some more goodies where this one came from (my wife got it for me from the lab at her work), but I don't know what they are yet (my wife has no idea what these things are, or what they are for!)
Out to try out my new toy now!!

Weather station

The Weather Station is finally complete! That is at least the beta stage!
(the beginning of the development was a long time ago)
Here is a picture of it standing outside:


It has been there for a few weeks now, since the 13th of December, enduring the snow and ice that this winter has brought us, sending a packet every 10 minutes.

The station is based on a JeeNode, with a LDR to sense the daylight, an SHT11 to sense temperature and humidity, and a home made anemometer to sense the wind speed. Here are some photos:

Complete setup, fits nicely inside an electrical box fit for the outside.

Details of the main box. The JeeNode is visible on the left. I had to take about half a millimeter from it in order to fit inside the box. I painted pin 1 of each port with tippex and put a dot in each of the ports to know which one is which as I kept having to refer to the datasheet. The whole thing is powered by 3 AA Alkaline batteries. The wholes that lead to a sensor are covered with corks to prevent water from coming into the brain of the station..

Detail of the light sensor: an LDR. The window I made by warming up a package of hard(ish) plastic and pushing it into the whole using a small spoon. All the electronics for each of the sensors are near the sensor itself, and only 3 cables leave the sensors: Vcc, Gnd and signal (except for the SHT11).

Detail of the SHT11. This one is floating, protected inside a little cheese box, painted white using tippex (I was too lazy to use proper paint...and it was cold outside to use it anyway...and the tippex was right in front of me...and I don't use tippex for anything...)

Detail of the anemometer. I used the center of a CD spindle, attached 3 half's of ping-pong balls, and improvised a bearing from a VHS recorder roller. It fitted nicely in some electrical tube. The sensor is a optical emitter/receiver in the same package. It has not been calibrated, as I only need an indication of the amount of wind, in order to automatically lift the sun screens.

The nice thing is that I initially built the sensors to work with 5V, as I always used arduinos, then the JeeNode uses 3.3V, so I thought I had to adapt some things...not for the light sensor, as it is a basic divider, but for the optocoupler. But I tried it, and it worked fine even at 3.3V!

I spent a lot of time fighting with low power modes of the JeeNode, and finally got it to some sort of power down...which I believe will allow it to work for a few months from the batteries...lets see...I will try to make a post about that soon, as it is also of interest for the JeeLabs community.

So far it has sent 3271 packets. Here are the latest ones:

3267 1 0 0.5 87.4 @ Tue Jan 5 21:26:58 2010
3268 1 0 0.5 87.2 @ Tue Jan 5 21:37:17 2010
3269 1 0 0.5 87.3 @ Tue Jan 5 21:47:37 2010
3270 1 0 0.4 87.6 @ Tue Jan 5 21:57:57 2010
3271 1 0 0.3 87.6 @ Tue Jan 5 22:08:17 2010

The sequence of numbers corresponds to: sequence number, light level, wind level, temperature in Celcius and relative humidity in %.

I have now to put the JeeLink receiver in the server to be able to put all data into a database and use it for something useful!

(2 posts in a day! great! it must be the cold outside...)

New Year!

Happy New Year!!

And this, I declared the "Bag Free Year" :) I explain: we have a bag in the kitchen, where we put all the bags we get from shopping, and, which are to be used in further shopping, garbage collection, etc. It is always our plan to carry a bag around in the pocket, so that we do not need to get one from the shop when buying something. I often have one in my bike rack, but still, the bag in the kitchen has been growing, as there are many occasions when we do not have a bag!
To add to the whole thing, the city where I live has started to collect plastic separately since the beginning of the year, so we decided to try to reduce the amount of plastic, and other garbage. In fact, we decided that if we have to buy a package, we will prefer the plastic ones! as those can go in the recycling instead of the burning oven. Metal is still allowed as that is easily separated.

So, to implement this I will place a paper in the kitchen, where we have to write every plastic bag we bring from the shops...sanctions are not yet in place...lets see what happens! maybe I create a pachube feed for the plastic bags :)

Lets hope this reduced the size of the bag in the kitchen!

Also in my plans is to measure how much garbage we generate by weighing all the garbage that leaves the house...but that is for later.

Meanwhile, have a happy New Year!

Temperature control

The weather station is almost ready. Due to complications, it took much longer than expected, but that will be the subject of a different post.
This one is about the temperature control system, of which I am very proud!

This year, since turning on the system, I had a problem, with the value of the actuator not being sent to the central, and since my control depended on it, it did not work. So I removed that dependency, since, as long as the desired temperature is higher than the current, the actuator will be open.

In the figure you can see a section of last week thursday, where the temperature was set to high for about 6 hours, and the actual temperature followed quite straightly.


Since the graphic is very compressed ( I only have 4 points per hour, thus 4 pixels per hour) normally it is difficult to see this!

The green line is the desired temperature, and the red is the current temperature.
The blue line in the bottom is the actuator, which is always at 0...

Here is a picture from last year, where the actuator was very visible.

Further news from the polar front

One more quick post about the polar coordinates display for the energy consumption.

I have adapted the graphics from the last post to have a logarithmic progression in the size, so that an increase of consumption would not lead to the bars going off screen, while allowing to see small variations as well. So this was the result:


Not bad in my opinion, but I think it is a bit too difficult to read, partly due to the difficulty in adjusting the coefficients such as to have a nice variation range.

So I decided to make it constant width and only change the color:


I think this is a better display, although the colors aren't the best...must work on that. The red area was the washing machine centrifuging the clothes!

One other idea, would be to combine the electricity and gas in one sole graphic displaying the cost, e.g. in euro, or in CO2 emissions!

Weather station

Finally, I decided to progress in the weather station front! mainly due to having received my JeeLink, and having successfully gotten it to work with the JeeNode!

So, the plan was to get a wind speed and amount of light measurement so that I could automate the sunscreens at my place. Of course, I didn't want to buy a commercial weather station, because the ones that do interface with the PC are expensive and you do not have much control, not to talk about Linux, which they probably won't support. So i had decided to take it in my own hands and build it myself!

Some time ago I got a light meter to work, and temperature I had already mastered, so all I needed was wind speed, and maybe direction, and a way to send data around, which was solve by the JeeStuff!

I have built the anemometer before the holidays, but did not have the opportunity to blog about it, so here goes a picture:



It was just a check of whether it moved in the wind, and if you look carefully you can even notice that it is rotating!

And today I bought a weather proof electrical box, and started the process.

First, the JeeNode did not fit inside, by an estimate 0.5 millimeters, so i had to get the dremel tool out and get a some of it sanded into dust, in order to fit.



Then I devised a transparent lid for the light sensor, which I will show you in a future post, when I get a decent picture of it. I did it by warming up some rigid package plastic and forcing it into the hole with a rounded end of a spoon. Then I cut it and inserted it, screwed it and it looks great! (in my opinion!)

I also made some sort of plugs/shield, but I am not yet 100% sure of how it should be.

I did decided to change all the electronics for the sensors to work with 3.3V.

The initial plan was to run it from 5V, but since the JeeNode has a 3.3 LDO regulator, it would be a waste of energy to have say 6V, converted to 5V for the sensors, converted to 3.3V for the jeeNode. And since soon this will all run from a battery and solar panel, the less power the better!

So tomorrow (or today, since it is pretty late) I'll have to redo the detection of rotations for the annemometer, and install the whole thing temporarily to see if all is functional!

I still have to figure out the temperature measurement, but I'll probably end up going with one of those temperature/relative humidity digital combined sensors, instead of the good old LM35.