From Gizmodo:

Satellite images can make it easier to get around when you’re using apps like Google Maps, but researchers at NASA’s Jet Propulsion Lab and the UK’s University of Bath believe advanced satellite imagery can also be used for a more critical purpose: analyzing structures like bridges for tiny movements that could be signs of potential collapse.


I saw that. It’s an interesting approach. I suspect it would be most useful for large structures. Smaller structures tend to be obstructed by trees in my area, and the sheer number of them would eat up a lot of processing power.

Millennium Towers in San Francisco is in the process of sinking into the ground; it has been for a few years and is involved in a bucket of litigation. Settlement and tilt is being measured by satellite. I understand it’s down about 1.5’… I haven’t checked lately… and will look this AM.

On another thread I mentioned the use of satellites to @Ron; I don’t know if it’s viable for his project.


dik…on that project, I had decided to go with accelerometers mounted at the four corners of the roof area; however, when we were doing our evaluation of the exterior envelope, the Condo Association hired a “project manager” to oversee the remediation construction. Well…the project manager decided that they needed to control how we did our engineering evaluation (the PM is not an engineer). I told them no, that we would not be constrained by their schedule or their input into our evaluation and withdrew from the project after providing them with a summary of what we had done to date. Yes, we will not realize about $200k (US) in fees, but I have no intention of allowing a non-engineer to dictate how I will do an evaluation.

1 Like

I can see a condo assoc hiring someone to do qc on the work to be completed. I don’t know why they would hire a PM to direct the evaluation. The evaluation requires a skilled individual(s), generally the reason you hire a qualified professional(s). A certain skill set is required for building envelopes.

Only thing I can think of is to try to reduce the remedy to the building envelope. Just a matter of time to see how that flies.

Several years back I was involved with determining movement as well as building envelope issues… used ZigBee for data recording… worked like a charm. We used thermal, moisture and pressure sensors in addition to accelerometers.


Thanks, Dik…took a look at ZigBee…might have a lot of application in my business for long term monitoring of the building envelope performance.

@Ron It’s extremely useful… has range and can have a huge number of sensors in the network. Much better than Bluetooth and has distance that Bluetooth doesn’t.

Should have added.,… the network can be secured. [I think of this stuff after I post]


I suffer from the same…too fast on the draw!

Thanks for the info.



Can you elaborate on the ZigBee network and how it was integrated with the various sensors? I’d like to understand more about this in case a file or incident arises where it could be useful…or maybe just point me to a page that talks more about it.


Well, welcome to the group(ies) CAB.

Good to see you in here.

I’ll put together some stuff… it’ll take a couple of days… I’ll check with my network tekkie to see if there is something better.

Forgot to welcome you to the menagerie.


Haven’t forgotten… just been busy. This arrived in my mailbox this AM:

@CharlieAlphaBravo , @Ron


@CharlieAlphaBravo @Ron @Zed I did forget…

Sorry for not posting earlier… my apologies… I forgot.

You can purchase a Zigbee network interface on a USB stick that you can plug into a laptop or desktop. They are about $20CAN. Zigbee interfaces also work with Android devices, I understand. I’ve not used them with Android. Software is installed the allows you to access the Zigbee network. That’s basically it. I’m considering whatever is connected to your network as a device. I think Zigbee networks and devices conform to the IEEE 802.15.4 Standard.

The networks can be configured as a ‘cluster’, a ‘mesh’ or a ‘star’. I’ve only used a star configuration. It allows a simple addition or deletion to the network without interfering with any other devices. The centre of the star is the coordinator (PC Box) that controls the network.

There are real advantages to zigbee. You can connect a large number of devices (in the order of 65,000. They are low power; this allows the devices to be connected for a long time. The devices have to have their own power supply; batteries can last for months. The devices can have a ‘sleep mode’ to further reduce their power consumption.

Zigbee networks are slow and are not used for rapid data transmission. This is not normally an issue with sensing devices.

Devices can be added or removed from the network, by software and also physically removed very easily. There is no disruption to the rest of the network, unless you are using a cluster configuration. Even with a cluster or mesh, if one device fails, it does not precipitate failure of the network.

The devices have a fairly long range (a few hundred feet) and with boosters, the range can be substantially increased.

Since zigbee is ‘open sourced’ there are numerous open sourced software packages for controlling the network. There is a proprietary zigbee workalike called Z-Wave that is operated by a company (name escapes me) that has Z-Wave products that may or may not interface with Zigbee devices. The company ‘strictly’ controls the operation of their devices. The software is normally easy to install and to use.

The devices include temperature, pressure, humidity, electrical, stress/strain, and a whole bunch of others. They also include smart home devices for lights (including hue), switches, thermostats, etc.

There is a robust Zigbee following that can provide information on the hundreds of devices available and offer guidance. They are very active and knowledgeable and helpful.

The networks are relatively secure using 128 bit encryption. This is not normally an issue since the sensor data is not normally ‘critical’.

Any one that can add/correct the above is welcome to do so…


Found this… shows where Zigbee ‘fits in’.

Zigbee.pdf (402.6 KB)


Awesome. Thanks for the 101.

The types of sensors that I might want to use would be like the Blastmate vibration/seismic monitors or perhaps a laser distometer to monitor the location of a critical spot on a structure. Also temperature and relative humidity. Also maybe a strain gauge for monitoring a crack or critical component. Can all these types of things be worked into a network?

@CharlieAlphaBravo One of first times I encountered the use of Zigbee was up in Bancroft, Ontario and it was used for measuring vibrations from blasting. This was 10 years before I used it myself, and I wish I had have been a little more curious and found out how it worked. They were taking multiple readings over a period of several months. should be able to assist you with any help/questions you need.


@CharlieAlphaBravo @Ron Just ended up in my in basket…


1 Like

@dik…Thanks. Good info

I tend to be a bit of an ‘info junkie’… ever since I was a little kid. Our family is into homeschooling and all the kids and grand kids read like adults at an age where I was just learning to read.