After trawling the internet for some time, I still can’t seem to get a defnititve answer for my project requirement.
The requirement is to have accelerometer sensors connected to gym equipment and the movement data to be sent to the cloud for analysis. Something like below:
50 - 100 accelerometer sensors
Connecting to hub (Imp wifi? BTLE? ZigBee?)
Maximum battery life (Rechargeable? Disposable? 3 months of life? 1 Year?) Battery life very important
i have been working with an mpu 9250, a small common module, hooked up to an arduino nano, capturing data, (yaw, pitch,roll,) and then sending the data fron the nano via a xbee module to a matching xbee module then passing the data via uart to the imp. This data can then be plotted in ubidots, in different forms. So in theory your project could work depending on your time and skill & resources. At the moment both these modules are seperated, the xbee module has a range of about 100 mtrs using xbee pro series 2, running on lipo battery. naturally battery life depends on data rate, sleep modes, many variables. in my case the imp and xbee receiver is just powered from my pc port, but also could be battery powered. while this is not the same as your project, it has some of the concepts. i am doing this on my own, with a lot of trial and error in code, i am just learning the imp, ( imp 001 and april board), so you need to consider the imp that will be used in final product. what you are planning could work, should work, only you can decide. code available if you want. TOM.
Is the movement only to detect if the equipment is being used, or are you attempting to actually get real values from the sensors? I assume it would be a small sensor for each piece of equipment (with a battery), and it is mounted somewhere out of sight?
Here is something that costs $60 each:
Or the “activity sensor”:
It is “wireless”, but I assume it sends data to a receiver/router which would be connected to the data hub, such as a PC. I don’t see the word “WiFi” used. I do see a USB Gateway that connects to a PC. It has a coin battery. This is their description of battery life.
"Battery Life At 1 hour heartbeat setting, coin cell battery will typically last ~ 1-2 Years."
I’m assuming your sample rate would be more frequent. If you are looking at which equipment is being used, you would probably sample every 5 or 10 minutes? Let’s say your battery life would then be closer to 3-4 months?
If you do an Imp thing, your final costs would probably be more than $60 unless you have a custom circuit board made, and then you have design, build, manufacturing costs. And then you have to do all of the software stuff.
What if someone DID create an Imp WiFi version of an “activity monitor”? Perhaps an Imp005 with an accelerometer and coin battery. All built into a small plastic package that can be affixed to something. Perhaps a wash machine or dryer in an apartment. Stick it on the back and monitor it. Nobody would see it, but it would tell you when the machine was in use.
The same thing stuck to piece of gym equipment. Which machines are currently in use? Let’s check the website and see.
I know people have already made Imp “washing machine in use” projects, but to make one very small, with a coin battery, and a battery life of 6 months? I don’t have time or finances to build it, but it would be really cool.
I suggest you don’t attach an imp005 to a coin-cell battery just yet. At present the imp005’s power consumption is way above that of other imps, and it has no deep-sleep modes. We currently intend to reduce imp005’s power consumption (and add deep-sleep support) in a future firmware release, but it’s never going to be as low-power as imp003 (or as the forthcoming imp004).