simple and cheap way of logging several different temperatures needed

[Brandon]

I need a method of logging the temperatures of about 10 pipes in a system that I need some information from to help try and diagnose.

Whilst  I am  happy to have a go at putting something together, programming is not a subject that I have managed to get my head around as yet.

I do not require real time updates, or internet access, just something that can be set, and then retrieved and downloaded after a period of time.

Thanks in advance for your help.

Brandon.

[guydewdney]

http://cpc.farnell.com/pico-technology/adc-20/datalogger-hi-res/dp/IN04734

8 @ 180 quid - is that 'cheap'?

or 4 at 75 quid
http://cgi.ebay.co.uk/VELLEMAN-SA-PCS10-4CH-4-CHANNELS-DATALOGGER-/380261910790?pt=LH_DefaultDomain_3&hash=item5889604906

[wookey]

You could get one of these: http://sites.google.com/a/usapiens.com/opnode/products/opn-one and 10 1-wire sensors. The catch is that I don't think the opn-one can log for long on its own. You need something to receive the xAP info and save it. Can be any PC/laptop/netbook with some suitable software or the opn-max.
No programing involved - all pointy and clicky. The opnode sensors aren;t the ideal form factor for measuring pipes. I really must get my pipe sensors made - been a bit busy this year.

[ericw]

Brandon,

I know it is not going to help with your immediate problem, but I'm intending creating such a device based on an Arduino/RTC/SD shield or a Stalker to collect data from Halfbees and other 1 wire sensors and log it to an SD card for later analysis.

Eric

[Baz]

I have used the pico devices at work but they require a PC.
For single channel I have an EL-USB-1 which is stand alone and logs every minute only one channel for over a month. Actually a great device generally to stick in a room, fridge, car for a few days and see the fluctuations. Uses 1 battery per year (maplins). Also used at work for proving we really don't like working in 28C one day and 17C the next 'cos they can't fix the aircon thermostat.
http://www.lascarelectronics.com/temperaturedatalogger.php?datalogger=101
They do a cheaper version too now.

[profp]

I came across these recently, and they look like they might get you some or all of the way there:
http://www.airsensor.co.uk/shop.html?page=shop.product_details&flypage=flypage.tpl&product_id=1&category_id=4

It should be relatively straightforward to connect multiple temperature sensors to a single device, may be worth contacting them to see if they can help. Fits your requirements for 'fit and forget, collect the data later'.

Maxim iButtons may suit your needs, depending on how long you need to log for. Independent, minature, data loggers - you just attach and they record, collect the data later by placing the button on a reader attached to a PC. The cost starts to mount up for 10 of them though. e.g. http://www.qasupplies.com/smartemlog.html

Alternatively, Quasar do a four-port board for a sane price:

http://www.quasarelectronics.com/3145-ds18s20-computer-serial-temperature-data-logger.htm

There used to be a ten-port board which was pretty much identical, but sadly I can't find a link for it now. Obviously needs a PC to log the data though.

P.

[KenB]

Hi,

I'm making a system based on Arduino, SD card shield and pipe-clip thermistors from Rapid Electronics. It's intended to be cheap and cheerful and intended for solar thermal or other domestic energy logging tasks.

I found a neat design for an open-source datalogger called Openlog.  http://www.sparkfun.com/commerce/product_info.php?products_id=9530

Whilst Sparkfun Electronics produce a small board for OpenLog for $25 (intended originally for model rocket telemetry) it's really just an ATmega processor interfaced to an SDcard - so you can easily port this code onto the NuElectronics Freeduino/SDCard and most likely the Seeed Stalker board.

OpenLog sets up FAT16 or FAT32 directory structure on the SDcard and allows all serial data (from whatever source) to be logged to a txt file.

I'm also working on very cheap Arduino-like serial slaves.  The ATmega328 processor can be bought for under £3, and you can have a functionally equivalent unit to and  Arduino built on stripboard or even breadboard, for under a fiver.  Each slave can directly read up to 6 thermistors or 1-wire devices and send its data back to the SDcard equipped Arduino which is running the OpenLog code.

If your interested, I've put the detail on my blog -  http://sustburbia.blogspot.com/   with a series of posts beginning in June.

I should also mention some neat graph-plotting software called KST  http://kst-plot.kde.org/    This will take a file or serial data stream and plot it in real time.

Having just got back from mediterranean Spain this afternoon - I have to admit the central heating is on tonight!  Welcome to the logging season!



Ken

[KenB]

Having just re-read Brandon's original post, I see that there could potentially be a demand for a low cost system, some sort of a kit based on readily available parts, which very requires little effort to set it up, with connections being made with screw-terminals etc.

Sounds a bit like the mythical "Navitrino" system we discussed last year. The good news is that we are getting there,- slowly.


Ken

[StBarnabas]

Brandon,

I know it is not going to help with your immediate problem, but I'm intending creating such a device based on an Arduino/RTC/SD shield or a Stalker to collect data from Halfbees and other 1 wire sensors and log it to an SD card for later analysis.

Eric

Brandon
it may be a bit too early but I look at where HalfBee was a year ago - Eric sending me code which kept on falling over. Now we have ADCs , counters, switches, flow meters, irradiance sensors etc. Given another 6 months or so we hopefully will be there.

Sean

[desperate]

Ken

A simple kit is just what I would be willing to buy, I would like to measure and remotely display about 10 pipe temps, dont need to log any data or control anything, is that feasable?

Desperate

[Kombi]

Having just re-read Brandon's original post, I see that there could potentially be a demand for a low cost system, some sort of a kit based on readily available parts, which very requires little effort to set it up, with connections being made with screw-terminals etc.

Absolutely. I am after such a system, accessible for dummies like me, where I can log pipe temp in about 6 to 10 locations and then retrieve the data to analyse it.

[Baz]

If you just want the temperature, no logging, prepared for a little bit of soldering how about this.

The IC LM35DZ is a little thing that looks like a transistor. You connect a voltage to 2 of the pins and the other gives you a voltage proportional to the temperature. It will pickup a fair bit of noise on the wires so will need smoothing and filtering and I have never tried it over more than a yard but in theory is should be ok over some distance. So there you have a voltage you can measure with a 5 quid DVM from Maplin N20AX and a dozen can go through a switch (maplin part FF73Q). Print out a calibration table for millivolts to farenheight if you need to.
http://www.gbnetwork.co.uk/circuits/lm35a.pdf

Maplin no longer stock this chip, they are getting pretty hopeless. Farnell and Digikey have it but beware astronomic shipping charges.
who'sd have thought we would have to use ebay for component supply.
http://cgi.ebay.co.uk/LM35DZ-Linear-Temp-Sensor-IC-TO92-Qty-3-NEW-/320583760356?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item4aa447f9e4

[KenB]

Desperate,

I can give you 6 or 8 temperature readings easily, then you need to add a chip to give more channels, so you end up with 13 or 15.

This is all do-able for about £40 (+VAT) of parts for a 6 channel setup.  Beyond 6 you need an additional multiplexer chip and a board to mount it on.  Each additional pipe clip sensor you add is £1.80 plus VAT.

http://www.rapidonline.com/Electronic-Components/Sensors/Thermal-Sensors/Pipe-clip-temperature-sensors/76422/kw/

You'll need these:

LCD      http://www.nuelectronics.com/estore/index.php?main_page=product_info&products_id=2

Arduino http://www.nuelectronics.com/estore/index.php?main_page=product_info&cPath=1&products_id=14

And if you want more than 6 channels - this would be useful

http://www.nuelectronics.com/estore/index.php?main_page=product_info&cPath=1&products_id=3


Total for Arduino plus display is £28,  then £2 per sensor  then add the VAT.


Ken

[StBarnabas]

Desperate,

I can give you 6 or 8 temperature readings easily, then you need to add a chip to give more channels, so you end up with 13 or 15.

This is all do-able for about £40 (+VAT) of parts for a 6 channel setup.  Beyond 6 you need an additional multiplexer chip and a board to mount it on.  Each additional pipe clip sensor you add is £1.80 plus VAT.

http://www.rapidonline.com/Electronic-Components/Sensors/Thermal-Sensors/Pipe-clip-temperature-sensors/76422/kw/

Ken

Ken
thanks. These look like nice thermistor based devices. How does your software convert the resistance values to temperature? I was thinking of  using an RC  time with a comparator and a look up table.
Sean

[ericw]

Although very convenient and cheap is the tolerance of +/- 1.0 to 1.6 degrees (depending on type) rather going to limit the usefulness of the pipe sensors, unless you go through a calibration setup.

Although the price is going up, DS18B20's ( £13 for 10 on Ebay) must still be a contender in the low cost stakes especially as you don't need to have multiplexors when the number of exceeds the number of analog pins on the Arduino.

Eric