Temp/humidity data logger - Page 1
Forum section: electronics / testgear

author: skYfIrE
author_rank: Contributor
timestamp: February 24, 2020, 06:10:56 pm
content: Hi,I'm looking for a temperature / rel. humidity data logger for my lab. This data logger is used to record the ambiant temp and humidity in my lab.I would like to get a precision of 0,1°C / 1% RH but I don't want to use battery (a plug on 220V is required) and a display (if possible with backlight).I have only found a Fluke 1620A but the price is pretty high, we're around $2000 and the precision is too high for my needs.Anyone knows how can I find a solution which is not so expansive and not so accurate ?

author: james_s
author_rank: Super Contributor
timestamp: February 24, 2020, 08:46:10 pm
content: This sounds like the sort of thing you could build in an afternoon with an arduino clone, the main cost will be the sensor.I built an environmental logger using a esp8266 but mine pushes the data out to dweet rather than storing locally.

author: nfmax
author_rank: Super Contributor
timestamp: February 24, 2020, 09:21:59 pm
content: I hope you mean aresolutionof 0.1˚C & 1%, not an accuracy - that would be difficult to achieve at a reasonable cost. I use a Pico HumidiProbe USB temperature/humidity probe, which has aresolutionof 0.01˚C & 0.1% Unfortunately they are no longer made, but you might find one on eBay. They come with PC software, which displays & logs the data, but it's not very good (e.g. the logs don't include a timestamp!) and the interface format is proprietary.

author: angrybird
author_rank: Regular Contributor
timestamp: February 24, 2020, 10:00:31 pm
content: My two chirps on SMD humidity (which include temperature) sensors:1) The humidity sensors I've worked with are all SMD. These sensors need to be "baked" after soldering to re-normalize their output characteristics. Once normalized, as long as they are subjected to environmental and electrical parameters within the datasheet limitations, they "should" provide output to a degree of accuracy and repeatability that meets the datasheet specifications.2) With that being chirped, I must say that my experience with these SMD humidity sensors is that even once normalized, they are better suited for delta measurements, i.e. difference between two conditions, as opposed to absolute measurements. Humidity measurement is tricky and there are many limitations which apply to these silicon based sensors.Overall, I'm happy with them due to their size and easy digital interface, but you need to thoughtfully consider the requirements for your application in order to determine if these (easily) obtainable sensors are appropriate for your application.

author: skYfIrE
author_rank: Contributor
timestamp: February 25, 2020, 12:28:45 pm
content: Thanks for all your answers but you go deeper than I thought. I need a plug and play solution from a manufacturer.I mean a device like this one :@nfmax, you're right, I've made a mistake, I need aresolutionof 0,1°C and 1% RH.

author: malagas_on_fire
author_rank: Frequent Contributor
timestamp: February 25, 2020, 12:55:35 pm
content: what about this model- Search terms: humidity data logger 0.1ºChttps://ebay.us/WR0ebIThis is just a sample unbranded model, choose you're location . Quick edit check if accuracy meets you're critera as well

author: nfmax
author_rank: Super Contributor
timestamp: February 25, 2020, 02:06:00 pm
content: My local datalogger company, Lascar, may have something suitable for you:https://www.lascarelectronics.com/data-loggers/temperature-humidity?orderBy=priceLowToHigh&type=display

author: angrybird
author_rank: Regular Contributor
timestamp: February 25, 2020, 02:17:37 pm
content: Quote from: malagas_on_fire on February 25, 2020, 12:55:35 pmI've used these generic devices and be aware that the humidity measurements are highly subjective to the measurement conditions and in my experience are not useful for absolute measurements.

author: kilobyte
author_rank: Regular Contributor
timestamp: February 25, 2020, 03:25:48 pm
content: Maybe have a look for the OPUS 20 series from Lufft.They have different Options like Pressure, Power over Ethernet etc.Querx THP from egnite are also some small data loggers.They probably are using something like a SHT35 as a sensor element.

author: skYfIrE
author_rank: Contributor
timestamp: February 26, 2020, 05:32:44 pm
content: @malagas_on_fireThe product you've found could be fine because it could use 220V network. For the price I'm not sure this device will be reliable and it won't be possible to get a certificate of calibration.@nfmaxSorry but you have read too fast, I need a device which uses the 220V network to not use batteries.@angrybirdsThanks for your comments on this product.@kilobyteOPUS 20 series from Lufft, hmmmm, it's a good challenger ! I need to check all version which are available.Querx THP doesn't have a display.