Bushwalk Australia

Hi all,
Have been looking around to get a digital thermometer ideally with the following features:-

- Must have max\min memory so I can see the previous minimum temp overnight
- Waterproof if possible
- Small/lightweight of course

I want it so I can get a better understanding of how well my gear is working. So far Ive found a couple :-

Coghlans Digital Dangler
Pyle PAW1 watch

Wondering if anyone else uses something like this and what you use?

cheers

Or you could look at a cheap alternative from Jaycare.

http://search.jaycar.com.au/search?w=xc-0341&view=list

wander wrote:Or you could look at a cheap alternative from Jaycare.

http://search.jaycar.com.au/search?w=xc-0341&view=list

The Coghlan's one is about $9.00 on eBay.

Andrew

I use a cheap one I picked up from Jaycar - works well and weighs about 30g. Actually got it for home brewing, but it has been on a few trips. Pic here: https://picasaweb.google.com/lh/photo/4 ... directlink

Thanks all for the tips...III check out JayCar for starters and see how I go.

I ended up getting a Coghlans Digital Dangler (what a name) just because it was small and compact.
Its a very simple device. The max/min function just retains the absolute max/min temperature since last reset.
If you dont reset it for a week you will get the max/min over the entire week.
So just need to remember to reset it each night before hitting the sack to get the overnight minimum.

LandSailor wrote:I ended up getting a Coghlans Digital Dangler (what a name) just because it was small and compact.
Its a very simple device. The max/min function just retains the absolute max/min temperature since last reset.
If you dont reset it for a week you will get the max/min over the entire week.
So just need to remember to reset it each night before hitting the sack to get the overnight minimum.

dangler.JPG

dangler_side.JPG

dangler_face.jpg

how accurate is it?

Will let you know..yet to compare it with any other thermometers.
Probably going to be corrected here but I wasnt too concerned about the accuracy as I believe electronic thermometers generally tend to be accurate by nature (assuming no other factors like direct sunlight or body warmth). The technology involved is cheap and effective.
Anyway will see how it goes..

I purchased a digital thermometer for my esky, an Eva Kool brand that cost me over 30.00. Was surprised when i read the instructions, it said accurate to within 2 degrees if my memory serves me right. I to was always under the impression that they where more accurate

Yeah, the questionable accuracy of nearly all the ones I've seen is the reason I haven't ended up buying one yet. I like the idea of knowing the max/min temp but don't want to be carrying something I don't trust.

I guess for accuracy a dedicated pocket weather station would be the way to go like the Kestrel models, accurate to 0.1°C
http://www.kestrel3000.com.au/

Or I'm thinking one of the new garmin tempe things might be the go? can't find much on the functionality though
https://buy.garmin.com/shop/shop.do?pID=107335&ra=true

I have just been playing with a Garmin Tempe after I saw one at Valentines Hut over Easter. I bought it to go with my new eTrex 30 which provides the readout capability - Current temperature and min and max in the last 24 hours. Weight just under 10g. The clip works well onto thin guy lines and 20mm webbing but should fit 25mm webbing. As to accuracy there is no specification provided by Garmin but in Basecamp the temperature is recorded against each track point to 0.1 degrees. On the eTrex 30 it shows in whole degrees. A really nice little gadget - and we all love gadgets.

How accurate this is? You need to be careful not to confuse the relative accuracy (difference between one reading and the next) and the accuracy against the temperature scale. Most electronic temperature devices are accurate to about 0.1 degree over their range but you need to standardise the unit against a known temperature source to know the offset - this is the +-2 degrees mentioned above (real temperature 10 deg, unit reads 11). Having used 20 mercury thermometers for a scientific study and had to calibrate them, they were all over the place - way over the 2 degrees difference. I am not fussed about the offset difference as a degree isn't important except for bragging (-7 at Whites River last Sunday morning).

I have a bunch of these laying around. You've just given me an idea

Mark F wrote:Having used 20 mercury thermometers for a scientific study

This must have been a fair few years ago now, Mark?

Mark F wrote:How accurate this is? You need to be careful not to confuse the relative accuracy (difference between one reading and the next) and the accuracy against the temperature scale. Most electronic temperature devices are accurate to about 0.1 degree over their range but you need to standardise the unit against a known temperature source to know the offset - this is the +-2 degrees mentioned above (real temperature 10 deg, unit reads 11). Having used 20 mercury thermometers for a scientific study and had to calibrate them, they were all over the place - way over the 2 degrees difference. I am not fussed about the offset difference as a degree isn't important except for bragging (-7 at Whites River last Sunday morning).

Hi Mark, are you trying to explain the difference between accuracy and precision here and calling 'relative accuracy' what should be called precision unknowingly or am I just confused? (it's not hard sometimes ) Accuracy is how close a measured value is to the actual or true value & precision is how close each of the measured values are to each other. The offset that you mention with some thermometers is probably the same thing as bias, for example some devices will always read +1 of a degree above the actual value, so 11 if it's 10° or 25 if it's really 24 and so on. Meaning that instrument has a high precision but an accuracy bias of +1 degree. I don't know what scientific study you were doing but 2 degrees sounds like a lot of difference, it might have been easier to just dunk your toes in

I don't know why the garmin website is so lacking in information regarding accuracy or pretty much anything else about the tempe, maybe to cover their *&^%$#@!, but a few good reviews are popping up and from what I've seen I'm keen to get one before I go on my next winter trip out west, I know it doesn't really make a difference to a trip knowing how cold it really gets but bragging rights alone make it worth the $30!

Here's a couple of links which have some info, how "accurate" anything off the net is poses another question though...

http://forums.groundspeak.com/GC/index. ... pic=301101

Precision wise - when it comes to accuracy of the Tempe device I've checked my product against a reference thermometer and it read within 0.3°C@0C/0.4°C@20°C

Sounds reasonable enough.

and it seems some of the earlier models have a fault that can only be fixed by replacing it with a newer version.
http://garminmontanagpsr.wikispaces.com/Tempe

My use of technical language is sadly lacking (forgotten) since my time at UTAS in the late 80's. Hopefully readers gleaned the ideas. While digital thermometers are relatively linear the old glass thermometers wavered around. To calibrate them you used to place them in an ice bath to determine freezing and then in boiling water. With the readings you could then develop a linear equation for each individual thermometer to convert each reading from that thermometer to a standard scale. This assumed that the behavior of each thermometer was linear. The aim of the experiment was to observe the development of a nighttime inversion across an open to wooded boundary (did it at the Springs). Teaches you to camp in the trees if possible.

These days we would just use temperature loggers

Mark F wrote:I have just been playing with a Garmin Tempe after I saw one at Valentines Hut over Easter.

Mark..does the Garmin Tempe need to have your GPS running to record the temperature? Or can it run as a stand-alone datalogger?
Just wondering if you need to have the GPS on overnight to get the minimum temperature.

The Tempe keeps recording even when the gps is off. It doesn't have a memory apart from the maximum and minimum so you cannot get a time series of temperatures for the period when the gps is off. When you turn on the gps then it gets the three values (current, max and min) from the Tempe every minute or so. If you left the gps on and set the Track log recording interval to time and set an appropriate time gap then the GPS should (I haven't tried it) act as a data logger.

Mark F wrote:The Tempe keeps recording even when the gps is off. It doesn't have a memory apart from the maximum and minimum so you cannot get a time series of temperatures for the period when the gps is off. When you turn on the gps then it gets the three values (current, max and min) from the Tempe every minute or so. If you left the gps on and set the Track log recording interval to time and set an appropriate time gap then the GPS should (I haven't tried it) act as a data logger.

Hi

Brilliant post. Will have a play as I have two. One for the Fenix and one for the 62S and both were consistent with each other.

Cheers

Mark F wrote:The Tempe keeps recording even when the gps is off. It doesn't have a memory apart from the maximum and minimum so you cannot get a time series of temperatures for the period when the gps is off. When you turn on the gps then it gets the three values (current, max and min) from the Tempe every minute or so. If you left the gps on and set the Track log recording interval to time and set an appropriate time gap then the GPS should (I haven't tried it) act as a data logger.

Interesting thanks...just have to remember to check the max/min each morning.
There are a few lightweight USB temperature dataloggers around, a little bit more pricey but otherwise set and forget.
And hopefully reasonably accurate if designed for commercial use

USB Temperature Data Loggers

Jaycar - Temperature/Humidity Datalogger

DataQ - Temperature Data Loggers

Could someone explain how to get an Etrex 30 to display the temperature in a data field? I have updated the software and connected the Tempe via ANT- but can't work out the next step.

Thanks Charlie

Mark F wrote:My use of technical language is sadly lacking (forgotten) since my time at UTAS in the late 80's. Hopefully readers gleaned the ideas.

My apologies for being a pedant Mark, I was in the middle of brushing up on a whole bunch of definitions, including accuracy & precision etc for Uni when I saw your post in this topic You're explanation was clearer than mine by the way, how I got a distinction for that subject I don't know

The Perambulator wrote:Could someone explain how to get an Etrex 30 to display the temperature in a data field? I have updated the software and connected the Tempe via ANT- but can't work out the next step.

Thanks Charlie

Hi Charlie, I have the etrex 30 as well & got a Tempe last week. I've had a bit of a play around with it so I think I can help. I changed one of the data fields on the compass page to display the current temperature and then changed two of the fields in the trip computer page to display the min and the max temps.

If you go to any page that has a data field on it and press the menu button a menu appears (shocking, I know), select 'change data fields' and then select the one you want to change. In the next menu scroll through until you find 'Temperature' (or '24 max/min temperature if that's what you want) & voila!

Out of curiosity I placed mine in a fridge then freezer the other day as a test. It's a fairly new fridge/freezer with digital temperature readouts of 3°C and -18° respectively and i was getting a steady reading of 3 and -18 within a minute of placing it in each one. I was surprised at how quick and accurate it was & after I pulled it out it slowly warmed up to the ambient room temp and was reading the same as the wall thermometer at 21°C.

[

The Perambulator wrote:Could someone explain how to get an Etrex 30 to display the temperature in a data field? I have updated the software and connected the Tempe via ANT- but can't work out the next step.

Thanks Charlie

Hi Charlie, I have the etrex 30 as well & got a Tempe last week. I've had a bit of a play around with it so I think I can help. I changed one of the data fields on the compass page to display the current temperature and then changed two of the fields in the trip computer page to display the min and the max temps.

If you go to any page that has a data field on it and press the menu button a menu appears (shocking, I know), select 'change data fields' and then select the one you want to change. In the next menu scroll through until you find 'Temperature' (or '24 max/min temperature if that's what you want) & voila!

Out of curiosity I placed mine in a fridge then freezer the other day as a test. It's a fairly new fridge/freezer with digital temperature readouts of 3°C and -18° respectively and i was getting a steady reading of 3 and -18 within a minute of placing it in each one. I was surprised at how quick and accurate it was & after I pulled it out it slowly warmed up to the ambient room temp and was reading the same as the wall thermometer at 21°C.[/quote]

Many thanks for the reply, sorry for taking so long to acknowledge your post, but I trawled through You Tube and found a video by GPS City explaining how to do it - as you explained - than forgot about my post. After updating the software the temperature was not available in a data field- so I attempted to update again and hey presto it appeared just like it should. Thanks again

LandSailor wrote:I ended up getting a Coghlans Digital Dangler (what a name) just because it was small and compact.
Its a very simple device. The max/min function just retains the absolute max/min temperature since last reset.
If you dont reset it for a week you will get the max/min over the entire week.
So just need to remember to reset it each night before hitting the sack to get the overnight minimum.

dangler.JPG

dangler_side.JPG

dangler_face.jpg

AWESOME!!!!
I spent ages trawling the interweb a couple of years ago trying to find a way I could measure the max and min temps on a walk (and pref changes too).
The best I got was a heavy brass marine gauge or a $50 digital watch (which I bought) that only does once-per-hour measurments.
I'll be chasing one of these
Steve

Bad news Im afraid. Yesterday I bought a food thermometer. I put the food thermometer and my Coghlans digital Dangler in the fridge overnight.
The Dangler showed an overnight minimum of 5 degrees whereas the food thermometer showed 3 degrees when I opened the fridge in the morning.
Based on a quick google, the standard fridge temperature should be approx 3 degrees or lower, so either my fridge and food thermometer are both incorrect or the coghlans digital dangler is a couple of degrees out. At room temperature the dangler and the food thermometer showed close to identical reading.

Make of that what you will, but looks like the digital dangler shows a significant loss of accuracy as the temperature decreases. Which of course, makes it totally useless for my intended purpose (record the overnight minimum).

Damn annoying! Might try the Garmin thingy as my next option.

LandSailor wrote:Bad news Im afraid. Yesterday I bought a food thermometer. I put the food thermometer and my Coghlans digital Dangler in the fridge overnight.
The Dangler showed an overnight minimum of 5 degrees whereas the food thermometer showed 3 degrees when I opened the fridge in the morning.
Based on a quick google, the standard fridge temperature should be approx 3 degrees or lower, so either my fridge and food thermometer are both incorrect or the coghlans digital dangler is a couple of degrees out. At room temperature the dangler and the food thermometer showed close to identical reading.

Make of that what you will, but looks like the digital dangler shows a significant loss of accuracy as the temperature decreases. Which of course, makes it totally useless for my intended purpose (record the overnight minimum).

Damn annoying! Might try the Garmin thingy as my next option.

Bummer! Thanks for the info. Please keep posting the results of your experiments as I'm sure many people here would be interested.
I'll hold off on the CDD then for a while.
cheers
Steve

LandSailor wrote:Bad news Im afraid. Yesterday I bought a food thermometer. I put the food thermometer and my Coghlans digital Dangler in the fridge overnight.
The Dangler showed an overnight minimum of 5 degrees whereas the food thermometer showed 3 degrees when I opened the fridge in the morning.
Based on a quick google, the standard fridge temperature should be approx 3 degrees or lower, so either my fridge and food thermometer are both incorrect or the coghlans digital dangler is a couple of degrees out. At room temperature the dangler and the food thermometer showed close to identical reading.

Make of that what you will, but looks like the digital dangler shows a significant loss of accuracy as the temperature decreases. Which of course, makes it totally useless for my intended purpose (record the overnight minimum).

Damn annoying! Might try the Garmin thingy as my next option.

I honestly don't think you can conclude anything from this. Thermometers are generally only accurate +-2C anyway.

Well I guess I was comparing it to the USB dataloggers I looked at. Most of them I looked at seemed to be 1 degree accurate for the cheapies and 0.5 degrees for the more expensive.
Reading this rather dense article and without understanding all of it, it said that thermistors can be very accurate but only within a defined range. Once you move away from that range the accuracy decreases which seems a little like what happened for me.

LandSailor wrote:Reading this rather dense article[/url] and without understanding all of it, it said that thermistors can be very accurate but only within a defined range. Once you move away from that range the accuracy decreases which seems a little like what happened for me.

Perhaps, but still no way of knowing which of yours is more inaccurate. Short of further testing of course.

What is the defined range and accuracy of the DD?