Temperature sensor

[Wole]

Even if it's a pity that there isn't a permanent solution yet, I'm reassured that my findings, which I shared in my last post, have been confirmed.

Maybe there is still a solution to the problem.

[svartbjorn]

since these external devices almost all have the possibility of downloading the data in txt or csv format where there is a time stamp and the monitored data, perhaps the data could simply be combined at the end of the respective recordings.
Unless it is essential for the user to see everything immediately on Locus as is the case for cyclists who want heart rate and power always visible.

1) Yes, that is what I was thinking of also. LM4 would then be able to create a continuous graph at the end with no missed data. Downloading all data from the sensor is a command in the SensorBlue app, so I guess this is a command available in the API.
2) If you have the screen on all the time and Locus in the foregroud (which is typical I guess when bicycling), updated temperature/humidity are shown correctly as long as you use the workaround of turning the screen off/on at least every 25 minutes (see earlier posts). I have the "Turn Off" command in the bottom menu in LM4, so this operation is quickly done with 1 tap to turn off, followed by double-tap on the screen to turn it on again (also suggested by another user). However, if I put Locus in the background, I can see from the track statistics graph that sensor data stop flowing after anything from some few minutes to 20 minutes (I was not able to see any consistency).

However, both the above tricks I guess may be replaced by a beacon or restart command from LM4 to the sensor with regular intervals to keep the data flow alive (just guessing, since I don't know the API).

[svartbjorn]

Menion - you said you couldn't get the CR2477 battery in your country. Hint - it is available from several stores at AliExpress. Attention: it is available as non-rechargable 3.0V (CR2477) and as rechargable 3.6V (LIR2477). The micro-controller inside the WS07/WS08, the PHY6202, can run at max 3.6V according to its specifications, but I wouldn't take the chance to use a 3.6V battery. So - make sure you get the non-rechargable 3.0V battery - CR2477.

[Wole]

Hello Menion, I would also appreciate it if a connection could also be created for the Inkbird IBS-TH2.

I got the sensor. The advantage is that the sensor is really waterproof and is therefore better suited for outdoor use.

[Will C]

Hi Wole. I asked for an alternative sensor a while back Tempodisc they have an sdk available on their site. I have 3 of their sensors, one temperature only and fully waterproof, the other temp and humidity which is not waterproof. High quality product available directly from supplier based in UK and USA or via amazon. Locus connects to the sensor but can't read any data sadly. My request didn't gain traction so I moved on to the garmin ecosystem for recording all my activity data, using the tempe for temperature, so instead of using locus daily, I now use it only occasionally. The sensor blue option is not waterproof and therefore not really rugged enough for general outdoor use. The inkbird looks good, if not quite large, and the price is affordable. Maybe its an option too?

[Wole]

Hello Will C, as I said before, I bought the Inkbird. He makes a very good impression, but cannot be connected to Locus.
Hence my wish for Menion to create a solution here.

The Tempodisc is too bulky and expensive for me.

[Will C]

Hi Wole, agree regarding the price but would like to say they are small and very light. Waterproofness us important to me, we've already had over 2300mm of rain here  so far this year 

[svartbjorn]

The WS07/WS08 can easily be made waterproof by putting them into a plastic bag. Adjusting to change of ambient temperature may take longer time since the whole unit has to adjust. However the sensor chip is mounted on a PCB (Printed Circuit Board) inside the case (I have opened it and reverse engineered the board), so even in open air the PCB has to adjust to ambient temperature before the temperature reading is correct. Also the case will affect the reading until it is adjusted to the ambient conditions. This is also true for a sensor that is rated waterproof. So why not simply use a platic bag. That is my plan. But humidity can't be sensed when sealed, since the humidity sensor chip necessarily has to be in contact with ambient air.

By the way - the Inkbird IBS-TH2 has a liquid rating of IP 4, meaning it is not guaranteed to withstand heavy rain for more than 10 minutes (refer the definition of IPX4).

[Wole]

If the WS07 is put in a plastic bag, the ambient temperature will probably never be displayed correctly. There must always be direct contact with the environment. With a plastic bag, however, there will always be a higher temperature.

At the moment I've put a rubber ring around the device itself so that moisture could only get in through the necessary opening at the back. This has not yet happened.

According to my experience and also according to statements I googled, IPX 4 is completely sufficient for normal outdoor use in the rain.

[svartbjorn]

If the WS07 is put in a plastic bag, the ambient temperature will probably never be displayed correctly. There must always be direct contact with the environment. With a plastic bag, however, there will always be a higher temperature.

No, that is totally wrong. I am a computer designer and have also designed integrated circuits, so I know very well how these devices work and are designed. And I have designed several smart devices with temperature sensors. A temperature sensor is a tiny chip, which is sealed in a small plastic package. That package is mounted on a Prinetd Circuit Board (PCB). A plastic bag around that will make absolutely no effect on temperature reading as long as no heat is generated inside the plastic bag. The power consumption of the WS07 is extremely low - so low that it is totally negligable. The temperature in that plastic bag will necessarily reach  ambient temperature, and since a plastic bag has very, very low insulation effect, the device inside the plastic bag will very quickly reach ambient temperature.

A humidity sensor necessarily has to sense the ambient air. But water/rain into the sensor opening will also propagate further onto the PCB and other devices on that PCB if it is not designed waterproof (e.g. WS07). That moisture will eventually distroy some of the devices on the PCB. Particularly capacitors, but also resistors and plastic IC packages, are volnurable to moisture and are prone to fail after some time if exposed to moisture. I have experienced failure after 2 years of the humidity sensor I used in two of my own smart device designs, although they were never exposed to rain directly.

[Will C]

Having tested the WS07 sensors extensively. I can say with confidence that the already very slow response to temperature changes is much slower when the sensor is placed in a small bag. I even made a bag out of goretex. Other issues come into play when sunlight hits the bag. Side by side the bagged one reaches a significantly higher temperature. I chose an IP64 rated device which lives on the outside of my pack but it only records temperature in its own app. I prefer to have all my activity data in one app so moved to the garmin ecosystem. Their temperature sensor does not have an IP rating but has been tested by users down to 10m (too deep for bluetooth comms). In the end I chose waterproof devices over one that's not because where I live, if it's not raining it's either just stopped or about to start. Currently I own 7 sensors in 4 different types. Maybe I have a problem 😜

[svartbjorn]

Your experiences make absolutely sense and are what I would expect. Slower response is expected, how much depending upon the insulation effect of the bag. But eventually it will be correct. If sunlight hits the bag, you will for sure get a significantly higher temperature obviously. A plastic bag in sunlight is identical to a greenhouse. Correct reading in sunlight is a challenge no matter how the sensor is encapsulated. Have you seen professional temperature sensor stations? They are big with several large white discs in a stack to create a proper shielding to sunshine. When I suggested a plastic bag, that was for rainy conditions with no sunshine. I agree that a waterproof unit is absolutely to prefer, but as long as LM4 does not support any such devices, WS07/WS08 is what we have for LM4, and using a plastic bag when rain is a workaround that I can live with.

I also have the Garmin Tempe sensor connected to my Fenix 3 watch. It is strange that the Tempe case is black, since black absorbes sunlight while white reflects sunlight. That is why professional temperature sensor stations are white. The Tempe sensor is one example of a completely sealed case with no direct contact between the sensor and ambient air. That is why it is waterproof. So Tempe, just like WS07 in a plastic bag, depends upon the whole unit to cool down/heat up to reach ambient temperature before you get correct reading.

[Andrew Heard]

FWIW https://en.wikipedia.org/wiki/Stevenson_screen

[Wole]

Here is my solution in pictures. I am currently using a WS08 sensor. I sealed the opening of the two parts with a waterproof rubber ring (image 1), then attached the sensor to my mobile phone holder with the necessary openings facing down. Then the mobile phone itself comes over the sensor (image 2). This means that the sensor is also largely covered at the top. At this angle, no rain can get into the sensor from below either.

In this constellation I have been driving for months without any problems, even in the rain.

I don't need a bag that is opened or closed depending on the weather, apart from the fact that a bag always poses the risk of falsifying the temperature (it's always cooler outside than inside, regardless of the weather).

The problems remain, of course, on the one hand that the connection breaks off after about 30 minutes and, above all, the great inertia of the sensor.

[Will C]

Hi, I agree about the Stevenson screen, I operate 3 weather stations which utilise Stevenson screens. Good discussion folks.