SteamyTea

What kind of freight goes in your trains, is is a lot of domestic refuse?

Nor does the Fat Controller But you might get this:

Jeremy You could totally redesign the lawnmower. All that research you did at Culdrose should come in handy. Probably best to wait till Now 5th for the initial tests. You would also find out how strong the window film is. Just think, you could 'mow' the lawn from several thousand miles away

Should really be repeated about 20 times though (not that I think it actually matters for these). Until an experiment has been repeated several times, it is hard to know if a run was a fluke, or a true reading. 20 runs and you can get a confidence of about 5%.

I thought it was Ada Lovelace that was the mother of computing. I am personally not interested about the legalities of copyright and patents, that is for people that lack imagination. I developed a plastics system that overcame a problem, tried to sell it, no one was interested. So quite happy to take that to the grave. Not as if it is life changing, unless your boat or aeroplane fails. Much more interesting what you can do with 'others' inventions. I once bit a chunk out of my tongue, took about 3 weeks to sort itself out. I am still careful when I eat anything chewy.

I found the ones I got were very good. If they are made under license, I can't see any reason that they should be worse than US made ones. US made ones probably come from China anyway.

An RPi model A. I made up a connector with a bit of vero board and some terminal blocks, plus a resistor. Shall post up a picture when I get home (up your way at the moment).

That is a good thing. At that price, a quick calibration check and throw out the bad ones is all that is needed. May even drill a long hole in the floor for one.

May order some when I get home, good price.

Can't open the link

I did some training for ASLEF once, got to 'sit with the driver'. Fascinating journey. 110 MPH does not seem fast from the cab, the signals appear quite quickly and, at the time, the driver had to swap over safety system. Much more complicated than I ever imagined. Then there are the track sitters to deal with, not something I could cope with.

I think the easiest and cheapest option to fit PV would be to make up your own frame to take regular modules.

You may be able to get a small air to water heat pump that can suck out a few kWhs of energy at the right temperature, and if it can modulate low enough, could be used to control the overall temperature in the conservatory. It does mean that you will be having a few tonnes of outside air coming into the conservatory every day, which may have an impact on the rest of the house. I don't think there is a simple and cheap DIY method to do it. You may be better making the overhang out of PV modules or some ST panels and just use the electricity/thermal energy to heat the water in a cylinder and contribute to the ASHP running (make/buy a diverter). You will possibly find that your overall heating costs are pretty low, say less than £250/year. Water will probably be half that, so with those low levels of spend, the concept of return on investment becomes pointless (I spend more on going for a coffee each week than I do on my energy bills).

I picked up some clear drinking straws yesterday, they look the right diameter to stick the DS18B20s in, so just need to get some silicone.

As I had a couple of hours free yesterday and my 9 DS18B20s had been running a couple of days, I thought I would look at how precise the readings where. I cannot really check accuracy as I do not have a calibrated thermometer to check them against. So what I did was to create a range of temperatures that are imaginary true ones. Then look at the spread of readings in each bin range. This is pretty easy in a spreadsheet, just list a range of temperatures (I rounded down to 1 decimal point the lowest temperature then incremented up by 0.1°C). Then I looked at means between the the bin below and the bin above i.e. Temp bin below < DS18B20 reading > Temp bin above. This makes for a very quick visual comparison in a spreadsheet as the DS18B20 mean should be pretty close to the "imaginary" temperature. Some numbers are going to follow now. If I take the minimum temperatures recorded by all sensors first. 14.6°C (Imaginary), 14.72, 14.71, 14.69, 14.70, 14.75, 14.71, 14.75, 14.75, 14.70 Then the maxium 24.4°C (Imaginary), 24.50, 24.51, 24.50, 24.51, 24.51, 24.47, 24.47, 24.47, 24.52 Then the highest overall count (this gets really nerdy). Sensor 1, Count 528, Imaginary Temp 18.3, Mean Temp 18.30 Sensor 2, Count 517, Imaginary Temp 18.2, Mean Temp 18.20 Sensor 3, Count 480, Imaginary Temp 18.2, Mean Temp 18.19 Sensor 4, Count 526, Imaginary Temp 18.2, Mean Temp 18.19 Sensor 5, Count 542, Imaginary Temp 18.2, Mean Temp 18.19 Sensor 6, Count 559, Imaginary Temp 18.0, Mean Temp 18.01 Sensor 7, Count 579, Imaginary Temp 18.4, Mean Temp 18.37 Sensor 8, Count 579, Imaginary Temp 18.4, Mean Temp 18.37 Sensor 9, Count 638, Imaginary Temp 18.0, Mean Temp 18.01 So it seems that these cheap DS18B20s are pretty precise in the temperature range I have so far tested, not more than 0.15°C out, which is neither her nor there for what we are using them for. I have also not had any errors in the 11,166 readings I have taken over the last couple of days. I am sampling every 13.59 seconds overall. I also had a look at the standard error of the mean, but that is really so low that it is not worth mentioning, but I will anyway 0.03°C max. Now to really go overboard with the stats, I also looked at the median and modal values. The biggest difference from the imaginary temperature was 0.1°C on the modal values (as expected as there are not many readings, but not counted them.) The main thing here is that all the values are very close together, between -0.09 and 0.10°C over a range of 10.2° shows that the logged temperatures are pretty well normally distributed. This is a good thing when testing, as more accurate assumption can be drawn. Not sure what conclusion can be drawn from this, apart from the precision of these very cheap sensors is plenty good enough for me.

If you call a landline from a VOIP phone, what number is displayed? I ask this as I use a call blocker on my mobile, stopped my Mother calling as she had a masked number (until I unmasked it so she could call her mate).

May have to look into that as it is better than the deal I am getting. 4G works well when it is working.

I know ways to make them waterproof enough. I find a small bucket or large pickle jar quite good as the rate of cooling is slower, can then sample at a slower rate and get a more accurate result. But, as you say, in the real world it is not that important.

I go from P/Type to P/Type 1, P/Type 2, P/Type 3... Then stuff it in a box. Got my 9 sensors up and running now, shall leave them on a bit and see what they get up to. Then I can get out my 'calibration' sensor and add that to them. Then find a way to dunk them is a bucket of water without them shorting. 24/03/2017 11:22:33,27.75,27.75,27.187,27.187,27.125,27.187,27.187,28.062,27.375 24/03/2017 11:22:47,27.375,27.375,26.75,26.937,26.625,26.812,26.75,27.75,27.0 24/03/2017 11:23:00,27.0,27.0,26.375,26.625,26.25,26.5,26.375,27.437,26.687 24/03/2017 11:23:14,26.687,26.687,26.125,26.375,25.937,26.187,26.062,27.125,26.375 24/03/2017 11:23:27,26.375,26.375,25.875,26.062,25.75,25.937,25.75,26.812,26.062 24/03/2017 11:23:41,26.125,26.125,25.625,25.812,25.5,25.687,25.562,26.5,25.812 24/03/2017 11:23:56,25.812,25.812,25.312,25.5,25.187,25.375,25.25,26.187,25.5 24/03/2017 11:24:10,25.562,25.562,25.125,25.312,25.0,25.187,25.0,25.937,25.25 24/03/2017 11:24:23,25.312,25.312,24.875,25.062,24.812,24.937,24.812,25.687,25.062 24/03/2017 11:24:38,25.125,25.125,24.687,24.875,24.625,24.75,24.687,25.437,24.812 24/03/2017 11:24:51,24.875,24.875,24.5,24.687,24.437,24.5,24.5,25.25,24.625 24/03/2017 11:25:05,24.687,24.687,24.312,24.562,24.25,24.312,24.312,25.0,24.437 24/03/2017 11:25:19,24.5,24.5,24.187,24.375,24.125,24.187,24.187,24.812,24.312 24/03/2017 11:25:33,24.312,24.375,24.062,24.25,24.0,24.062,24.062,24.687,24.187 24/03/2017 11:25:46,24.187,24.187,23.937,24.062,23.937,23.937,23.937,24.687,24.0 24/03/2017 11:26:00,24.062,24.062,23.812,24.0,23.937,23.812,23.812,24.375,23.875 24/03/2017 11:26:13,23.937,23.937,23.687,23.875,23.687,23.687,23.75,24.25,23.75 24/03/2017 11:26:27,23.812,23.812,23.625,23.75,23.625,23.625,23.625,24.125,23.687 24/03/2017 11:26:40,23.75,23.75,23.562,23.687,23.562,23.5,23.562,24.0,23.562 24/03/2017 11:26:54,23.625,23.687,23.437,23.562,23.5,23.437,23.5,23.937,23.5 24/03/2017 11:27:07,23.562,23.562,23.375,23.5,23.437,23.375,23.437,23.812,23.437 24/03/2017 11:27:20,23.5,23.5,23.312,23.437,23.375,23.25,23.375,23.75,23.312 24/03/2017 11:27:34,23.437,23.437,23.312,23.375,23.312,23.25,23.312,23.687,23.25 24/03/2017 11:27:47,23.375,23.375,23.25,23.312,23.312,23.187,23.25,23.625,23.25 24/03/2017 11:28:01,23.312,23.312,23.187,23.25,23.25,23.125,23.187,23.562,23.187 24/03/2017 11:28:14,23.312,23.312,23.187,23.187,23.187,23.062,23.187,23.5,23.125 24/03/2017 11:28:28,23.25,23.25,23.125,23.187,23.187,23.062,23.125,23.437,23.062 24/03/2017 11:28:41,23.187,23.187,23.062,23.125,23.125,23.0,23.125,23.375,23.0 And just noticed that the second sensor is on the same address as the first. Bugger

You can get a letter from the DNO asking you to disconnect for a number of reasons. One is that the installer has not submitted the correct paperwork to them. It is best not to ignore those sorts of letter.

Got the soldering iron out at the moment. All seems fine now. May be different when I split them all up on different length cables, but that is for later. So a quick coding question. In Python, when you open up to read the sensors with: Sensor 4 tfile = open("/sys/bus/w1/devices/28-0316b2f96eff/w1_slave") # Read all of the text in the file. text = tfile.read() # Close the file now that the text has been read. tfile.close() After I have processed the data with: # Split the text with new lines (\n) and select the second line. secondline = text.split("\n")[1] # Split the line into words, referring to the spaces, and select the 10th word (counting from 0). temperaturedata = secondline.split(" ")[9] # The first two characters are "t=", so get rid of those and convert the temperature from a string to a number. temperature = float(temperaturedata[2:]) # Put the decimal point in the right place and display it. temperature = temperature / 1000 Can I move onto the next sensor without renaming the the tfile to say tfile1. What I have to do with the final temperature = temperature /1000 or I just keep printing out the same data. Not hard to rename them all with a simple number, just that I am lazy and wondering if it is necessary. Also reduces the chance of errors.

I am just setting up 9 sensors for calibration. Found that when I connect up 6 they are reliable, add a seventh one it goes flaky, add the eighth one and the whole lot crashes. May have to change the 47k resistor to something else (a 10k). All I do to calibrate them is to pick one sensor as a 'true' one and then plot the others against it. Then do some curve fitting in Excel, note down the equation and use that. The lag can be an issue, longer sampling times usually sorts that. They are not precision temperature sensors, but good enough for most things in a house. Terry Has T4 got a loose live wire? they can work using parasitic power, but when I tried I got a similar result, but the other way around.

In these cases where people are sent preposterous bills, is it the meter that is faulty, or something further up the chain?

Mixing in dry sand (play sand is usually dry) to the flow/top coat is a common method. As for thickness of material (the lay up), I would go for a minimum of 3 layers of 450g.m-2 (used to be called oz and a half). This should be about 3mm thick. It is easy enough to put some extra layers on the high traffic areas if you feel you need to. Most suppliers should be able to help you out with what you need. I have never layed up GRP onto OSB, so reluctant to comment. I do know that some MDFs can cause problems with delamination, as can some chip boards. The only way to find that out is to make up a sample and see how easy it falls apart. The main thing is to make sure everything is dry, and I mean really dry. Damp is the killer for polyester resins. If it goes cloudy when you first paint some resin on, stop.

Floor area is an interesting concept. Just looking at my kitchen as I type this. I have 600mm wide units, 3 in a row. Then a 50mm gap to the end of the wall by the door. Seems to me that building the walls the correct length to fit in with standard sizes can save money.