RoadTest: IDT Wireless Flow Rate, Humidity&Temp Sensing Kit
Author: aspork42
Creation date:
Evaluation Type: Development Boards & Tools
Did you receive all parts the manufacturer stated would be included in the package?: True
What other parts do you consider comparable to this product?:
What were the biggest problems encountered?: The only way to push data out to the cloud is Amazon AWS. Something else like MQTT or TCP/IP / HTTP would have been a home run.
Detailed Review:
This is an evaluation kit from a company call IDT designed to get some IDT hardware in the hands of engineers to build new products around. It features two main modules - one as a base station and one as a remote sensing station. The base station is a RaspberryPi Zero W with a custom hat (expansion board) featuring a low powered wireless chip, the ZWIR4512. The remote sensing station also has the ZWIR4512 chip to handle wireless communications to the base station, and also to serve as a controlling IC to two sensing modules. Those sensing modules are a gas flow sensor (FS2012-1010NG) rated from 0-10 liters / minute and a temperature and humidity sensor (HS3001). Both of those are sold from IDT. There is more about that in posts 2 and 4.
I have posted individual portions of this review as linked below:
2. Kit Comparison (mostly about the flow sensors)
(See also Initial Reactions and Power up)
When I got the box, it was very well packed and very well presented in a padded box. I was able to pull out both main modules and get them powered up and have real sensor data in roughly five minutes. I think that is a big win on IDT's part as these types of things are often finicky. The HS3001 temperature and humidity sensor was very responsive to placing my hand in front of it, despite being encased in a plastic enclosure. The flow sensor as well does a great job and is very reactive.
This kit seems to be very well thought out and well executed. All the components are high quality, and they work straight out of the box.The kit also comes with relavent sets of power cords, some tubing for the flow sensor, and some hardware like mini HDMI to HDMI adapter for the Pi.
In this blog post, I spend a lot of time going over the hardware and the demo software (website) provided by IDT.
/servlet/JiveServlet/downloadImage/38-32709-727128/pastedImage_4.png/servlet/JiveServlet/downloadImage/38-32709-727133/pastedImage_10.png
The two main components are the first two images above - the Wireless Hub (left) and the Sensor Cube (right). The sensor cube contains the other two sensors shown here - a flow sensor and a temperature & humidity sensor. They both talk over I2C to the ZWIR4512 chip. This chip is a very versatile SoC which contains a 32-bit ARM microprocessor, tons of GPIO, communication ports like I2C, SPI, Serial, plus analog inputs and two DACs. Additionally, its biggest feature is the wireless integration. It has a fully 802.15.4 radio operating in either US or European frequencies. It is FCC listed and compliant even when OEM'd into other products, as longs as the correct antenna is used. This saves designers from having to re-certify a device. It is also designed for mesh networking. Multiple devices can talk to each other, "hopping" over to the final network node. In this case, the final node would be the Wireless hub; since it bridges from the 802.15 network over to a computer with full networking capabilities.
Here is IDT's listing for the ZWIR chip which looks very useful on its own. It looked to be about €18 on one website, so not cheap; but powerful.
It also happens to be able to produce very low power consumption. I did some testing in this blog post and got some very good results for low power consumption. IDT has configured the sensor cube to be selectable between battery powered or USB powered (aka mains power). While on battery power, they recommend only installing the temperature & humidity sensor. While running in this mode, the entire cube can use as little as 0.4 mA of power. It does have to wake up to read the sensor and send it wirelessly but that process is very quick and still doesn't use much power. One other quirk that I found is that they configured the sensor cube to use two CR2032 batteries, and a switch must be activated to chose between battery & USB. This changes the power profile of the ZWIR chip but it otherwise is still reading the sensors a configurable interval and transmitting them accordingly; just like when on USB power. However, since the capacity of those batteries is so low, we wouldn't get much run time. The other way around is to use a portable battery pack plugged in the USB port, but then the chip consumes much more power and we once again lose our runtime. So it would have been nice for the selector switch just been for "low power mode" and the CR2032 batteries could have somehow been auto selected or run as battery backup for the USB jack.
One other thing that I found missing was a JTAG programming port. The ZWIR chips support programming over Serial and also over the air, but it would have been nice to see this to help the process along. They could have also made it easier to access demo programs on the Raspberry Pi. I took a look around and found an "IDT" folder with two .bin files that seem to be running the main scripts but nothing really that looked like a "getting started" guide or sample code.
There isn't software (as such) that goes with this exact kit. The way it functions is that the Sensor Hub boots up and creates a WIFI signal. You can then join the signal with your computer or smart phone. Once on, you go to a website served up by an Apache web server on the Pi and you are presented with an IDT screen. The first time on the website the user is prompted to chose between North America or Europe. This sets up the broadcast frequency of the ZWIR4512 wireless chip. After that, we are brought to the sensor viewing screen. Whichever sensors are installed in the sensor cube have their live values displayed on this screen in a graph.
The graph is somewhat interactive - at least it updates live and you can zoom in & out to view up to the last 600 seconds of sensor data. However, once the data scrolls off the end, it is gone forever. The sensor is designed to also allow integration into Amazon AWS. It will post JSON messages with the sensor data. This portion was a little disappointing as I don't have an AWS account and it is a pay-to-use service. I would have really liked the ability to use MQTT or HTTP Post or something else to push data off these devices. The other way would be to write my own code to run on the RaspberryPi to query the data and do what is needed. I was able to get live data from the sensor in literally minutes, so it would have made integration trivial if that was provided. I did take a couple of points off for this since it was so close but still I found it lacking.
That all being said, IDT supplied a note in the box stating that the kit is for evaluation purposes only and that no part of the kit should be built into a system. So that means we can't get too critical of certain features missing when in reality we are supposed to just try out the different components then build our own system and order the components raw.
Here is a walk-through of the web interface.
That will wrap up this Road Test! It has been great fun working with this kit and big thanks to the E14 team and IDT for putting it together. I got derailed for about three weeks during this process for a family emergency and four different week-long work trips so wasn't able to get as much testing done, but I will be sure to post later if I'm able to get back to it. My real goal is to integrate a version of the flow sensor into my reverse osmosis (RO) system to monitor usage but that will have to wait for another day...
Now that I'm wrapping up the road test, I had mentioned in a previous post about opening up the flow sensor to look at the actual element. Let me know in the comments if you think I should do this 
