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When you configure "Auto-Update" for a tag, the server will send a command to the tag to configure it to send periodic status update (with temperature etc) at specified interval. An "out of range" notification is sent when the server does not receive periodic status update from a tag at expected time + some margin.

Because the tag stores the interval configuration in its local volatile memory, if you remove the battery and reinsert it, the tag will forget about the periodic status update it is supposed to send. As a result, soon you will receive a false "out-of-range" notification even though the tag is well within range. When you "ping" the tag, it will come back in range right after. 

When the tag tries to transmit status update the transmission fails for some reason, it thinks it is out of range and will enter into a "hibernate" mode, where it no longer sends any status update until receiving a new command from the Tag Manager. If the status update fails for enough number of times to make the tag enter hibernate mode, and then recovers afterwards, the tag does not know about it and soon you will receive a false "out-of-range" message. 

We have made a simple yet effective change to the server-side algorithm to reduce these false out-of-range notifications: Just before the server is about to mark the tag "out-of-range", it automatically attempts to re-configure the tag's "Auto-Update" interval, and only marks the tag out of range when this fails. Now when you receive "out-of-range" notification you know with more certainty that the tag is really out of range. Because this change is done on the server side, no app date / firmware update is needed. 


a false "out of range" notification a false "out of range" notification "out-of-range"

We discovered a bug introduced by a firmware update in Long Range Motion Tag on September 15.

This can be reproduced by the following steps:

  1. Set auto-ping/auto-update to some value e.g. 30 seconds.
  2. Unplug tag manager power. 
  3. At scheduled time (e.g. after 30 seconds), the tag transmits and retries a few times.
  4. Re-plug in tag manager, the tag succeeds in transmitting update.
  5. After a while, the tag will flash several times and then becomes unresponsive until battery is taken out and re-inserted.

If tag manager is kept plugged in, if the tag ever has to re-transmit due to temporary interference, this problem may appear. As a result, the system will appear very unreliable, as any re-transmission will trigger this bug. 

This problem only affects Motion Sensor Tags that were shipped between September 15 and 26 2013. If you can reproduce this problem, Please send an email to, we will send you a prepaid return shipping label for you to return the tags for firmware update.


For long range sensor tags, if auto-update interval is set to be 5 minutes or longer, you may receive false out-of-range notifications followed by re-established link notification. This problem is caused by each tag sending updates at an longer interval of about 1.5x the configured interval. We have fixed this problem from the server side. To apply the fix to your set up, please from Web App, click Settings->Wireless... and change to some different frequency, and click Migrate. For tags that did not respond, a yellow "Migrate Settings" button will show up, click it to retry migration.  We apologize for the inconvenience.



In new installation of iOS app (v1.8) the push notification does not register. This issue has just been discovered and has been fixed in v1.9 App. The v1.9 App also provides other bug fixes and cleaner UI, and new features below.

  • Reordering tag. Click gear icon and choose reorder. The tags will appear in the same order on all devices. 
  • User Interface for future product prototypes that are still not in production. Please ignore these until supporting products are officially released.
    • Contact based door/window sensors
    • PIR sensors
    • Thermostats (Kumostats)
    • KumoApps (People's algorithms that runs on the Cloud to schedule & automate interaction among sensors and Kumostats. Compose and submit using KumoApp Coder ).



For those of you who tried out our beta version motion sensor tags, problems below were discovered thanks to your feedback, and were corrected in the release version:

  • After beep function is used, unless the beep duration was less than 3 seconds (beep until moved), the tag requires "reset state" to function properly afterwards. This issue was due to a simple bug and has been completely fixed in the release version. To avoid this issue in beta tag, don't use beep function, or always "reset state" after beep.
  • Searching new tag sometimes cannot find long range tag. When tag manager is searching an unassociated tag, it cannot use wireless parameters optimized for long range tag or it will not be able to find old version tags. To keep user interface simple (no separate button to search for long range tag,) a special wireless setting is used in the long range tag until it is associated. The issue has been corrected by optimizing this special wireless setting.  
  • Association sometimes fails and requires a retry. This was because the tag manager was not using the correct setting. This has been corrected from the server side. We tested search, association and un-association for 20+ times in succession without a single failure that would have required a retry.
  • Perceived short battery life. This can be improved by enabling low power receive mode. We added algorithms in the server to enable this automatically if the server determines the tag is well within range and does not need frequency calibration.
    Because the tag draws battery current in short pulses of few mSec, the battery voltage vs. time graph resembles the last plot "Pulse Discharge Characteristics" of As this plot shows, the battery starts from 3.2V, but quickly drops to 2.8V after only ~10% of its juice is gone, then it stays at 2.8V for ~75% of its lifetime. Since the battery percentage is calculated proportionally from the battery voltage, you will see the battery percentage drops very fast from 100% (3.2V) to ~60% (2.8V), then stays at 60% for a long time. This sometimes give people false impression of short battery life after seeing the battery percentage drops so fast initially.

Since Wireless Sensor Tags were released 1 year ago, they have been tried out by thousands of customers, many of whom have provided us with valuable feedback, bug reports and requests for new features and improvements. During the first few months of the release, we were updating the software almost daily to fix bugs and adding those improvements. 

However, one common issue that persisted is sporadic "loss of link" which is caused by the limited range and reliability of the wireless connection. People also noted that the sensor tag range reduced significantly when placed inside metal fridge or behind metal door. We then realized that the final hurdle to our initial goal, a product with lasting value, was to improve the wireless performance. 

We spent the last eight months not on ads or marketing, but on listening to our existing customers and building the best performing wireless platform possible for our application. Wireless Sensor Tags only need to send a few bytes once a while, while WLAN or Bluetooth are used to send megabytes of videos or voice, so they are clearly not efficient for our applications. Meanwhile new "narrow band radio" chips are emerging for applications such as wireless meter reading. They are able to reach kilometers range by using very low data rate and receiver bandwidth, using expensive frequency reference (crystals) and big antennas (and with radio operator license). Utilizing these new wireless technologies, we developed a solution using less expensive crystals and same antennas to keep the same form factor to achieve 4x improvement in the range. 

We did this by a combination of increasing output power to FCC limit, using optimal frequency modulation index, better crystal and new frequency control techniques to allow 7x narrower receiver bandwidth to filter noise. Completely new radio IC with better noise figure and rewritten firmware are used in each tag and tag manager. We completed FCC part 15.231a certification for both the tags and tag managers.

Taking advantage of the much improved range, we implemented features to trade-off range with battery life, because not every application requires such a long range.

  • The new radio IC we used contains a neat feature to turn off receiver immediately after it determines radio power within the narrow channel bandwidth to be no stronger than the background noise it estimated over the last few cycles. We fine tuned parameters to make this work perfectly on each Wireless Tags. The result is 1/4 of the receiver on duty cycle in stand-by (vs. the old sensor tags and with the mode disabled) and hence ~4x longer battery life (not considering power consumption of sensors like angle based motion).
  • We implemented transmit power control in each tag, i.e. the tag manager automatically send out command to each tag based on received signal strength, so that each tag uses just enough transmit power to reliably reach tag manager. This means if the tag is installed in a location close to the tag manager, its battery will last proportionally longer.

All these performance improvement and new features come at only $1 increase in cost to you. This covers the increased components for a new front-end filter, higher price of the new radio IC and a better crystal. 


We have added a new feature in Web/Android app to display temperature, moisture, or battery voltage history for multiple tags on the same screen. Access this feature from "Stats..." button at the bottom of the page. 

Meanwhile, we have re-tuned the database that stores these log data and added more indexes to significantly reduce the loading time for the statistics page.


We have started shipping Ethernet Tag Manager with new hardware on May 6. Those who received shipment notice on May 6 or later had initial problem of not being able to associate a tag until today (May 13). This problem was caused by a lack of web server support of a last minute firmware update made to the new Ethernet Tag Manager. We have just address this issue by adding the web server support. If you have experienced this issue, please try again and your problem should go away. Our apologies for any inconvenience this problem have caused. If you still have problem, please send email to We will reply to your email within 2~3 days. Our phone support will be back on May 30. 


The latest iOS app (version 1.7.2) and web interface ( now support low battery alarm feature. When configured for a tag (all types of tags are supported), user can receive email, tweet and/or push notifications when its battery voltage drops below the configured threshold. The notification can be configured to repeat per hour, per day or per week until the battery voltage goes above the threshold. 


From about 1 week ago, the cloud server that passes user commands to Tag Managers had experienced performance issue. During that time, motion event/temperature information upload from tag to the cloud server (via Tag Managers) was not affected, however, user who tried to beep, arm or disarm tags may have experienced very slow response and server timeout error. 

This was due to an change we made to server configuration (locally run our "user command" forwarding server that used to run on a separate Linux server on the same Windows web server) intended to reduce service down-time, but turns out the Windows port of the server software originally written for UNIX caused performance problems. 

We have recently restored the old server configuration and have confirmed that these issues are now resolved. We apologize for any inconvenience these issues have caused.


We have sold out all of our existing Tag Manager and will be shipping new Tag Manager hardware from orders received today. The lead time remains the same (no more than 7~10 days.) The new Tag Manager looks and will work exactly the same as the old one, and is 100% compatible with all existing Tags. It provides the following new features.

  • A better radio hardware for more reliable radio communication to tags and support of long range version Wireless Sensor Tags that will be released in Summer 2013. 
  • Due to temperature changes and aging, the crystal frequency in each Wireless Tag (old version) drifts. This prevents Tag Manager from using narrow receive bandwidth for long range. With the new tag manager the receive bandwidth can be programmed in several steps to achieve the best trade-off between robustness (against tag temperature change) and range. In narrower bandwidth modes, a "Calibrate Radio" button may appear when it detects frequency drift larger than the chosen receive bandwidth. Clicking this button to update frequency of each Tag to correct for the drift. If you set the Tag Manager to wide band mode (default) you will never see or have to use this button.
  • The hardware has capability to store up to 48 tag event transmissions (such as temperature update, motion events) locally while Internet connection is interrupted, and upload those to the Cloud server as soon as Internet connection is back. Each stored event will retain a time-stamp to indicate when it was actually received by the Tag Manager. 

We are now shipping moisture/water level sensor tag with firmware v1.4. It contains the following updates:

  1. v1.3 firmware had the problem of not able to reset out of "water detected" state unless manually do "reset states". This problem has been fixed.
  2. The tag writable flash memory is relocated to a "high endurance" region. This allows the tag flash memory to be wirelessly updated more than 100,000 times (v1.3 can update at least 1000 times). This is in preparation for our future version tag manager hardware which will allow continuous calibration of frequency offset caused by crystal drift when temperature changes. 

Like motion sensor tag v1.3 firmware update, if you are affected by above problem #1, please send the tag back to us for firmware update. We will perform the update and mail back within 3 business days. Please include your 4 digit order number on the package. Please send to:

Cao Gadgets LLC
Attn: Moisture Tag v1.4 update (Order #[Your 4 digit Shopify order number])
2 Welbury,
Aliso Viejo, CA 92656


We are upgrading our cloud server to larger memory plan currently. During this time will be down. We do not expect this down time to last more than 1 hour. 


On Nov 29 from around 11:30AM PST to 3PM PST, The and web site experienced service interruption. After it was restored around 3PM PST, many out of range or re-established link message may have been sent to you. Please disregard these messages. We have now disabled the out of range notification by default, so that you do not get these messages unless you specifically configure in the option to have out-of-range and re-established link messages sent. 

We have since determined the cause of this web site crash and configured IIS setting to reduce the chance of this happening again in future. 


 iOS app 1.7 with bug fixes related to sound not played has been released a few days ago. Web/Android App have been updated with the following new features. 

  • Setting auto-update interval individually for each tag;
  • A button to delete statistics/log data; 
  • An option in motion sensor config for silent arming/disarming.

On the server side, a few days ago, we fixed a bug that caused tag to become automatically "moved" state every time after it is armed, requiring a reset followed by motion sensor arm.

We are now shipping wireless sensor tags with improved firmware version 1.3. These tags are 100% compatible with the Ethernet Tag Managers you have. This firmware update improves reliability when the number of tags is large, and at low signal condition (signal level <-85dBm). It is expected to reduce the probability of the following issues happening due to low radio signal level:

  • False reporting that door/gate is open or closed, or open/closed event not reported.
  • A tag different from the tag moved reported to have moved.
  • Temperature exceeding threshold not reported. 
  • False reporting of re-established link from a tag that is known to be out-of-range. 

If you are experiencing the above issues frequently, and if you received your order before November 14, chances are you have the old 1.2 version firmware (You can also confirm this from tag version displayed on the web app, after temperature reading). We offer updating the 1.3 firmware to your tags free of charge, if you mail them (please send every tag you have) back to address below:

    Cao Gadgets, LLC
    RE: v1.3 update
    2 Welbury
    Aliso Viejo, CA 92656

 This update service is free without shipping charges even for international customers (will be sent using USPS Priority Mail Small Flat Rate Box), but we will not reimburse your cost for shipping to us. Please write your 4 digit order number (1xxx) from Shopify, address you want the updated tags to be send to (if different from your original order shipping address,) and the 12 digit tag manager serial number on your package. You can send an email to to give us a heads-up you sent them back (optional). We will update the firmware, and send back your tags within 48 hours after we received them.


iOS app "Wireless Tag List" version 1.6.1 with crash bug fixed is processing for AppStore. Please allow 24 hours for it to show up in AppStore around the world. This version supports 4 inch screen iPhone5, multiple tag manager (tap on the tag manager name to switch), and also setting auto-ping interval differently for each tags (this feature is not yet available in the Web/Android app interface.) By setting different auto-ping interval for different tags, you can make battery last longer for some tags while collect temperature data at desired frequency from other tags.

We also submitted iOS app version 1.7 for review. This version will no longer support iOS 4.3 and below. iOS 5.0 or above is required. In exchange, it has smaller app size for faster loading time. 


The iOS app version 1.6 has a bug that crashes at account registration (it still works if one register an account from the web interface then logs in to that account). We already submitted a bug fixed version 1.6.1 to AppStore for review 4 days ago. It should appear around Nov 11. 

Unfortunately, the AppStore does not have capability to roll back to previous version when the latest version is approved by AppStore review staff. To prevent more user installing this faulty version of iOS app we have temporarily delisted the iOS app from AppStore until Nov. 11 when version 1.6.1 is expected to the approved. 


We have just finished transitioning and, which are our web service the tag managers connect to, to a larger capacity Cloud server ( at Rackspace. The DNS record may require 1 hour or more to update. Meanwhile the old server will connect to the database in the new server to allow seamless transition. If you have ever experienced any 503 service unavailable error before, then these will much improve with this transition. 

However, there may be unexpected glitch, bugs, or service interruption caused by this transition. Please report any issues to These will be fixed as soon as they are reported. 


As promised, today we released a preliminary API documentation together with annotated source code of our Web app to show how to use them. These are JSON AJAX methods and can be called from almost any language on any platform. 

Most API requires log-in to use. When you receive our products in a few weeks, you will be able to try these out.