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We have some small updates to share today. 

Now in addition to sharing graphs of selected tags, you can share the entire "Recent Trend" screen or only data from selected tags. 

You can share tags/sensors from multiple tag managers on one URL and one screen. And you can control the order each tag appears by arranging the orders of the IDs appearing on the URL. Because this "shared" version of trend screen actually loads a bit faster than the general version, and is very flexible, we suggest also to bookmark it for your own use. 

Another small feature we added today is "range delete":

Before, you were only able to delete all data of the tag, or use the click to remove point feature. Now you are able to bulk delete points from selected date range. This feature will be useful when deleting temperature/RH data from testing periods, so one will only see the data when the tag/sensor is put into actual use. 

These features were added based on request from our customers we received just a couple days ago. Listening to customers like you and adding useful features like these is one of our top priority. If you want something and it makes sense, we will implement it right away! Please request in comment section below. 


Today we have released External Power Sensor Ambient Light (ALS). Building on the solid foundation of the Wireless Tag Pro ALS, the sensor supports all existing integration including IFTTT, KumoApps, Alexa, etc, while providing larger and non-volatile local memory for more reliable offline logging, as well as option for different types of batteries or wall plug.

Because the sensor is not intended to be carried around like tags, unlike Wireless Tag Pro ALS, it does not have beep to locate feature, or motion notification based on sudden change of light (i.e. you can beep it and beep will stop if you pick it up). The lower price point reflects this. 

Compared with current stock of regular External Power Sensor, hardware revision allows reading the voltage of the connected external battery up to 4.096V instead of reading only 3.3V or lower, for monitoring of wider range of batteries when there is still much life left. 

We are in the final stage of internal beta testing of External Power Sensor Indoor Air Quality (VOC). Integrated MOX (metal-oxide) based volatile organic compound (VOC, or any kind of smell) sensors are relatively new technology that allows indoor air quality to be measured with a much smaller physical size and cost than possible before. Inside the sensor there is a tiny metal-oxide element that is periodically heated to several hundreds of degrees Celsius by micro-heater, which allows its electrical resistance to vary with VOC, or smell in the air. Cooking, cigarette smoking, or human activity in general in a closed environment increases VOC while fresh outdoor air lowers it. 

Compared with temperature, humidity or ambient light sensing, because of the requirement to keep the MOX element at high temperature, the power consumption is larger as the sensor must be turned on at a fixed interval (every 6 second in our case). External Power Sensor is therefore an ideal vehicle for these sensors. Plugging into wall is the ideal way to use it, but since we are using a latest generation VOC sensor IC with industry leading low power consumption, one can expect to get several months of battery life with the available 1000mAh battery. 

We are excited of the kind of new application this new product might enable. Imagine installing the sensor in your rental properties or hotel room to monitor if tenant is smoking cigarette. Or cooking something when not supposed to. Combine with IFTTT to turn on a wemo switch that turns on your attic fan only when needed to keep air in your house always fresh. 

We expect to release it around the end of the year. Stay tuned! 

Click for product specifications

We ourselves use Wireless Tags to monitor vacation rentals, warehouse and hangars. We always wanted the tags to be there whenever we needed them, even after forgetting about them for months. But we are often disappointed to find out they have been unavailable with dead battery.


All lithium batteries die much more quickly in freezing temperature. Because of this, customers who use the tags to monitor inside of freezer are often disappointed that battery lasts only weeks, not months as they would outside freezer. 

External Power Sensor is the Answer. 



With flexible power source, you can connect much larger capacity, rechargeable batteries vs. the 225mAh CR2032 non-rechargeable battery used in regular Wireless Tags. For example, use the 1000mAh rechargeable battery bundle for 4x longer battery life than regular tags.  You can connect even larger battery or battery holder for inexpensive AAA batteries. 


Or, just plug the USB into wall of your building, or available USB slot on a server machine* to monitor server rooms for "zero maintenance".


If you also connect the rechargeable battery at the same time, built-in battery charger will keep the battery charged, which will immediately work as back up power when the building power fails. 


When tag manager is not available (because of building power failure, Internet outage, etc), logged data are stored in non-volatile memory (NVM) unlike regular Wireless Tag Pro which uses SRAM (data is lost when battery is removed).  Because of the NVM, data will not be lost when USB or battery is unplugged.  Only after the cloud confirms complete and successful data upload and storage, that the logged data in the NVM is erased. Since tag configuration ​(e.g. logging interval) are also stored in the NVM, upon reconnecting power, logging resumes automatically without configuration from the Tag Manager (which is currently done behind the scene from the cloud for regular tags). 




Click here for more details.




  With 1000mAh rechargeable battery bundle



4x the battery life of regular Wireless Tag.

Buy Now

Plugged into wall



Zero maintenance. 

Buy Now

* This product uses USB only for power, and physically has no capability to communicate via USB like USB memory sticks, so there is no concerns about compromising security when plugging into computers. 


We are now shipping ALS tags with new firmware (version 2.7) with below improvements:

  • When "buffer (transmit) multiple data point at a time" option is enabled, there can be corruption of locally stored data points (data are locally stored while tag is out of range or tag manager is offline.) This bug has been fixed. Because of this bug, for ALS tags shipped on or before June 10, 2019, please do not enable the option. The option has been automatically turned off on most of affected ALS tags that are currently online. 
  • Data upload speed is increased, to facilitate the use case when many tags need to upload. 

Unfortunately the firmware cannot be delivered remotely. If you need to receive these update, please mail the tags back, we will update them and ship to you free of charge. Please ship to

Cao Gadgets
Attn: ALS update for #[the 5 digit order number]
50 Tesla
Irvine, CA 92618 USA


Good news for you Smart Home fanboys, both Google Home and Alexa Smart Home skill for Wireless Sensor Tags are released today.

For Google Homeall of your tags will be recognized as "Thermostat" which can report current temperature and humidity as well as setting temperature monitoring thresholds. Setting the temperature will move the center point of the "comfort zone" i.e. average of the too hot/too cold threshold. Turning it on/off is equivalent to enable/disable temperature monitoring. The tags also support the "Locator" device type which will allow you beep the tag. The integration reports all real-time data to "Google Home Graph" so in near future you should be able to check your live temperature and humidity graph from Google products. 

For Alexa, there have been "Informational" skill that will require pronouncing "ask Wireless Tag" to open it, but allows more features (including getting humidity, high/low and average temperature during specified period, arming/disarm motion sensor, setting temperature monitoring thresholds), on the other hand the newly released Smart Home version uses "v3" of Alexa smart home API (which included support for temperature sensor) to support the most commonly used feature of getting temperature and motion state without pronouncing "Wireless Tag" to trigger it. 



If you have a wine cellar in your house, you probably know that keeping it at constant temperature is important.

If it is cold at night but hot during the day, the air inside each bottle contracts and expands, gradually loosen the cork, spoiling the wine inside. Temperature variation as little as 3°C can be bad for your wine. 

If air humidity is too low, the cork can dry up, if too high, mold can grow. While human prefers dryer climate, the optimum humidity for wine storage is between 60% and 80%. 

How do you check that your wine cellar temperature is stable enough, and humidity is always optimal, without staring at the thermometer 24/7? And what can do you if it is not? 

You will need:

Needless to say, you will get super easy to use temperature/humidity graphs (Example from actual wine cellar #1, #2, #3, #4, #5) by just placing the Wireless Tag inside the cellar, from which you can check daily temperature and humidity variations. 

First enable temperature and humidity monitoring from the Wireless Tag main interface (from clicking on the temperature and humidity buttons). 

Now you can use these IFTTT applets: turn on heat, turn off heat, turn on humidifier, turn off humidifier.  KumoApp, however, will provide more flexibility.  


After setup, you launch either iPhone or Android app for Wireless Tag while connected to the same WiFi as your WeMo plug. It should find the WeMo, and allows you to link the WeMo (from "+Associate" screen) so that it can be used by KumoApps.

Click the green KumoApp button. You will see these screens. Pick an app (rules) that allows you turn on a Wemo switch when it is too cold, and off when back to normal. There is also apps to turn on a Wemo switch when it is too dry, and turn it off when back to normal. Some KumoApps allows you to delay the turning on. You can also fine adjust the temperature monitoring in main interface to only trigger the KumoApp when N successive too cold/too dry readings are obtained.

When KumoApp was first released 5 years ago, it had been much less reliable. Since then, we have been continuously improving its reliability, and now KumoApp is entirely different from that time. We are confident to recommend using it this way. 


 We have worked very hard past few weeks to bring you a new app mode called "Trends": 

It is available in web and Android interface right now by clicking the "Temperatures" button on the upper right corner, and on iPhone/iPad app (version 3.0.0, expected to appear in App Store sometime later today), by swiping to the left, or pressing the "Trends" button on the tag list screen. 

The mode summarizes each sensor's temperature, humidity and ambient light, along with recent trend in a carefully designed layout. If monitoring is enabled, the too hot/cold regions are displayed on graph with red shadows, too wet/dry region by green shadows and too bright/dark region by blue shadows to show how much margin there is to abnormal conditions.

If event history was viewed (loaded), motion events such as "opened", "detected" are overlaid on the recent temperature graph, to help visualize possible causes of temperature spikes (iOS only).

Special server side data structure was designed such that recent data points used for this screen is always readily available, to ensure very fast screen load speed. 

We have overhauled much of our iOS app, so that it loads faster and supports iOS 12. On iPads, the split screen width now automatically adjusts to an optimal value, depending on what is displayed. App will automatically resume updating screen as sensor data comes in, when network connectivity is interrupted and later restored (the Web/Android version was already behaving this way). 

We are all ears for your feedback, and any ideas to make the app work even better for you. 


Today we have significantly improved the search/filter box in your Event History screen. 

The Event History puts all events in one screen in timeline format, but often we are only interested in one type of event or one particular tag. Until now, the search/filter box only applied filter (on the client side) to the events already downloaded from cloud so far, it looked ugly, and once you entered the search no new events could be downloaded from server as you scroll down. 

Now finally we have a "proper" filter box that allows you to filter with event type or tag name directly in the cloud. After you entered keyword, you will no longer see partially filled screen but enough relevant information will be pulled from the cloud and fill the screen. As you scroll down, only those events matching your keyword (of even type or tag name) will be downloaded. Also, when you press the "Update" button on the upper right corner, only those latest events matching your filter will be downloaded and added to the top of the list. 

Per suggestions from multiple customers, all manual temperature, humidity or soil moisture calibration are now recorded in the Event History. Just enter "cal" in the filter box to only see this type of event in a timeline. The date&time of the calibration, the raw temperature reading from sensor and the reading it was calibrated to, are now recorded and displayed. 

An existing feature that might be useful also, is the ability to add comments to each event in the "Event History".  From the web/Android interface, just press on the event, it will expand to reveal a text box to enter custom comments. 

If these new improvements are useful to you, please provide us with feedback by a comment.


Outdoor Probes Basic that ship after today (July 16) now support the SHT20 waterproof air humidity/temperature probe (SEN0227) in addition to the DS18B20 waterproof temperature probe. Simply connect either (not both) probe and select from the app the type of probe you have connected. 

The SHT20 air humidity/temperature sensor has 14-bit (0.01°C) temperature resolution and 12-bit (0.04%) humidity resolution,  the accuracy performance is equivalent to that of popular Wireless Sensor Tags Pro.  When selected, humidity monitoring (too wet/too dry notification) identical to that of Wireless Tag Pro becomes available from the app. The SHT20 based water proof probe is a great new-release product, which is also available from DigiKey and Mouser in addition to the manufacturer's website. 


Tag notifications like "moved" "opened" or "too hot" on the Android app are configured by default to use "speech", which makes the phone announce the event by human voice even when the app is not open or running. Some users absolutely loved it, while others really hated it when it fires off unexpectedly during meeting or in the middle of night.

There are three different volumes in Android namely "Music", "Alarm" and "Notification". You have to mute the "notification" volume to mute this announcement, which was not immediately obvious to many people. Besides, this also turns off other important audible notifications. Another way was to check off the "Use speech" box inside the app interface for each tag / type of monitoring individually, but you had to remember which tag had which monitoring enabled that may produce the sound, and check off one by one.

Now with Android 8, the Android app version 2.17.5 and above allows you to turn on/off any sound for each category of events like below (open Android system Settings -> Apps & notifications -> Notifications -> App notifications -> WirelessTag) 

Configuration for the category of events you have never received before will not be displayed, so on your device the screen may have fewer lines than the above. 

This must have been a much awaited feature for all Android users, and should have been implemented a long time ago. Please share your feedback using the comment button.


A new option "Buffer multiple temperature/humidity data points locally before updating" is being phased in to all of our products, starting from Outdoor Probe, Wireless Tag Pro & ALS.  This can be turned on and off at associate time or at "Special Options" (from the "More..." menu on iOS app or the chevron button under each tag from Web/Android interface.) When enabled, for example if you set logging interval to every 30 seconds, temperature (and humidity or brightness) is measured every 30 seconds, but radio transmitter is turned on only every 390 seconds to send 13 data points in each radio transmission.

As a result, when this option is enabled, you may not see the most recently measured temperature on the screen when you just opened the app, until you manually hit the update button. But the sensors would get a longer battery life at a given measurement interval because the radio transmitter, a major source of battery drain, is turned on much less often. Additionally, less radio congestion would allow more sensors/tags to be associated to a tag manager at a shorter logging interval. 

If you are using the sensor to just take periodic measurement to build a temperature log for example, this option is recommended. On the other hand, if you want to have the app always display the most recent temperature, please do not enable this option (This option is disabled by default). 



We have just enhanced "Limited user" account creation and management:

  • You can now create limited user accounts that may access tags from multiple tag managers. Simply press "Add a Limited User" button under another tag manager, then enter the same email/account name and password.
  • You can now view exactly what users have access to each tag manager, and remove access/unlink a user account from a tag manager, without completely deleting that user account. 

Also added is an option under the "Edit" button next to each tag manager, to "Ungroup" a tag manager if it is grouped with another. Previously you had to remove the tag manager then added it back without "group with" option.

Please be sure to clear browser cache or simply open these links (#1, #2), then press F5 key to force your browser to reload the web app code. 


Some of common feedback from our customer has been 

  • Battery life is too short. 
  • Sometimes tags go out of range or drop connection by itself
  • Want to use it for bar-b-que, swimming pool temperature or sauna temperature.
  • Want to use it to diagnose dishwasher, oven, or industrial fridge/freezer etc.

The core value our products provide has always been temperature monitoring and logging. In a way, we wanted to do one common thing uncommonly well. After nearly 2 years of development, the all new Wireless Sensor Tag Outdoor Probe features

  • 5 year battery life using 1/2AA battery
  • 3.6V battery allows DS18B20 water proof temperature probe with long cable
  • New generation processor (MCU) newer than ones used in any of our other products, provides lower sleep current and improved reliability (for example, low power brown out reset prevents accidental flash memory write)
  • IP68 rated, completely water proof enclosure resolves the problems of tag dropping connection (most common cause of this has been dew/condensation)
  • Better optimized PCB antenna, taking advantage of the larger circuit board, achieves slightly better range than regular tags despite the thicker, more robust plastic casing
  • 16-bit ADC for thermocouple and GE protimeter connection, along with accurate on-chip temperature logging 

These are available now for order and shipment within 3 days. Please comment on this blog post what you think. 



We have been using FreshDesk, an online ticket system to manage technical support requests for the last few years. Neither our customers nor our support staff were really happy about it:

  • It has no SPAM filter or ways to report SPAM emails, and we now get 2~3 times more SPAM emails than emails from customers
  • It has its own user account system separate from app account, which is not only confusing to our customers, but also forces our support staff asking for customer's account info in order to check their Tag setup.  
  • It requires cumbersome account email verification for everyone, which cannot be disabled despite many requests from other FreshDesk users wanting to disable it. This results in many customers not able to login to the system to view existing tickets.
  • It does not allow customers to search from FAQ or Knowledge Base first before submitting ticket. This results in our support staff having have to answer same questions repeatedly, and a drop in overall productivity in handling unique, valid customer requests.
  • It is too complicated with too many useless features; making it slow and inefficient to use.

We are finally fed up and developed our own integrated customer support portal: or (the correct one will be automatically chosen after you login).You can also access the portal from web interface by clicking on the "i" button on the bottom right corner. Now, only our real customers can create tickets. We automatically get info about your Tag setup from account associated with each ticket. The system also allows us to build Knowledge Base from past tickets so as our support staff resolves problems for a customer, future customers with the same issues automatically benefit. When we developed the system, like our other products, we tried hard to keep everything very concise and simple, which should greatly enhance our customer support productivity. 

You will only get emails when we reply to your ticket. You can add links to the comments, so if you need to attach a screenshot, please upload it to Google Drives etc. then include the URL.  


We are now shipping Water/Soil-Moisture Sensors with new firmware 2.5 which contains following significant improvements over previous versions:

  • A new option "transmit multiple data points at a time" can be enabled at associate time or at "Special Options." When enabled, for example if you set logging interval to every 30 seconds, temperature and soil-moisture is measured every 30 seconds, but radio transmitter is turned on only every 390 seconds to send 13 data points at once. This will significantly increase battery life where the transmitter is turned on every 30 seconds, (because of the overhead of sending a fixed "preambles" each time the transmitter is turned on.)  Additionally, less radio congestion would allow more sensors/tags to be associated to a tag manager at a shorter logging interval. 
  • Improvement in temperature and battery voltage resolution. The hardware was capable of approx. 0.4°F resolution measurement, but due to a bug in firmware, the resolution was artificially reduced to about 1°F previously. The battery voltage measurement resolution is also doubled. 
  • 70% improvement in moisture level measurement resolution. Previously, the setting was overly conservative to avoid counter overflow for some parts in low capacitance (dry) condition. We did study of part to part reading spread, and also added firmware logic to clip if there is overflow, which allowed us to increase the measurement time by 70% for higher resolution data especially in wet conditions. 

We are excited to announce that the Wireless Tag Android app version 2.15 and above includes an widget equivalent to iOS app's lock screen widget, to allow you to quickly check temperature, humidity, motion states, and last update time without launching the app. This must have been a much awaited feature for all Android users. 


Just like the iOS widget, you can put any number of tags from multiple locations / tag managers into the same widget. Press the pen button to configure. Press the dots button to switch between the view modes. Long press on the widget and release to resize to allow more information to be displayed. 

We have been too busy with new product development (rugged, water-tight wireless probe / thermocouple for pool, sauna, oven, engine CHT and other harsh environments, planned release Q3 2017), iOS app and server side scaling/enhancements and spent minimal resources on the Android app. As an iPhone user, I personally find the iOS lock screen widget extremely useful. So this feature for Android users is really really long overdue. 

If you have suggestions on the Android app can be further improved (other than re-writing the entire app replicating the HTML5 UI with native UI, which would be too much work), please let us know by adding your comment under this blog article. 


Actions are supported in the "Informational" skill as of today. Now you can say...

"Alexa, ask Wireless Tag to beep keys"
"Alexa, ask Wireless Tag to beep keys 5 times"
"Alexa, ask Wireless Tag to stop beep keys"

If you have tag named "keys". Arm or disarm motion sensor by saying ...

"Alexa, ask Wireless Tag to arm keys"
"Alexa, ask Wireless Tag to disarm keys"

Link a temperature sensor tag with a Nest or Honeywell WiFi thermostat in order to regulate temperature in a location different from where the thermostat is installed. If you have linked a thermostat named "Downstairs" and a tag named "Living Room", use it for the thermostat by saying ...

"Alexa, ask Wireless Tag to set downstairs at Living Room", or
"Alexa, ask Wireless Tag to use Living Room for downstairs".

The AC or heat is turned on when tag temperature monitoring reports "too hot" or "too cold". Change either the "too hot" or "too cold" threshold temperature by saying ...

"Alexa, ask Wireless Tag to set Living Room temperature to 70".

If you are in UK, the number here will be automatically interpreted as Celsius instead of Fahrenheit. You can also enable, disable or set thresholds for temperature, humidity or light monitoring by voice command, like ...

"Alexa, ask Wireless Tag to monitor temperature at Kitchen Freezer".
"Alexa, ask Wireless Tag to stop temperature monitoring at Kitchen Freezer".
"Alexa, ask Wireless Tag to set temperature at Kitchen Freezer between -40 and 0".
"Alexa, ask Wireless Tag to monitor humidity at Kitchen Freezer".
"Alexa, ask Wireless Tag to set humidity at Kitchen Freezer between 0 and 80".


Accelerometer Based Wireless Tag Pro detects motion not with 3D magnetic compass but with accelerometer, with benefit of immediate notification and ability to detect a small vibration that does not result in change of tag orientation (such as washer/dryer). It can also be used to detect vertical door (e.g. garage door) open/close but not horizontal door open/close. They come with 8192 point of memory for temperature and humidity like other Wireless Tag Pro. Order from here or here

Due to its limited customer base we have only produced them in small batches. We received another 500 yesterday. If you need rain proof version of this, please write in the comment section of this blog. If there is enough interest we will send half out for coating.


In September, we have released the Wireless Tag "smart home" skill. Due to limitation of the "smart home skill" category as defined by Amazon, although the skill allows actions such as "arm" or "beep" by voice command, we could not make Alexa return much useful information about each sensor such as temperature or motion state. 

Today, we are happy to announce the "Wireless Tag (Informational)" skill has passed certification and is now available to install. This skill is meant to supplement and be used together with the existing Wireless Tag smart home skill. As the name suggests, this skill is focused on having Alexa return useful information. 

Try saying: "Alexa, ask Wireless Tag for the lowest temperature last week." to know which sensor recorded the lowest temperature and how much.
"Alexa, ask Wireless Tag for the lowest temperature in Living Room last month".
"Alexa, ask Wireless Tag for the highest temperature in Fridge last week".

"Alexa, ask Wireless Tag for the temperature at boiler room yesterday." to know the average temperature yesterday there.
"Alexa, ask Wireless Tag for temperature at Living Room" to know the current temperature. 

Instead of "temperature", you can also ask about "humidity", "brightness", "moisture" or "motion state".

"Alexa, ask Wireless Tag what happened today" to have Alexa read back event history today, or "Alexa, ask Wireless Tag what happened at Fridge last week" to have Alexa read back events only related to the tag "Fridge", including what time Fridge was opened or about any temperature abnormalities, starting from the most recent.

You can also say...
"Alexa, ask Wireless Tag if Front Door is open"
"Alexa, ask Wireless Tag if Car Key is out of range"
"Alexa, ask Wireless Tag about the signal at Tag 1"

Here is a list of all possible things you can say (after "ask Wireless Tag", and skip the first column). 

The older smart home skill is better at recognizing unique names of tag you have given, while the "Wireless Tag (Informational)" skill recognizes from a list of most common 100 or so tag names such as "Living room" (complete list here) plus a number, which should cover over 95% of all names people have ever given to their sensor tags. If the skill has trouble recognizing your tag name, try to rename it to one on the list.


Wireless Sensor Tags Store was recently selected to join the Google Trusted Stores program. To help shoppers identify online merchants that offer a great shopping experience, the Google Trusted Store badge is awarded to e-commerce sites that demonstrate a track record of on-time shipping and excellent customer service. When visiting the, shoppers will see a Google Trusted Store badge and can click on it for more information.

As an added benefit, when a shopper makes a purchase at a Google Trusted Store, they have the option to select free purchase protection from Google. Then in the unlikely event of an issue with their purchase, they can request Google’s help, and Google will work with Wireless Sensor Tags and the customer to address the issue. As part of this, Google offers up to $1,000 lifetime purchase protection for eligible purchases.

Google Trusted Stores is entirely free, both for shoppers and for online stores. The program helps online stores like Wireless Sensor Tags attract new customers, increase sales and differentiate themselves by showing off their excellent service via the badge on their websites. For the shop to maintain Google Trusted Store badge, it has to ship at least 600 orders every quarter, and receive overwhelmingly positive reviews from survey emails automatically sent to each customer by Google. 

UPDATE (April 3, 2017) Google discontinues Google Trusted Store purchase protection program