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  • Author Author: ipv1
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[Firecracker Analyzer] [week 1] System Design and ReDesign

ipv1

I had already proposed a design but it was a bit rough and after talking to some sensor vendors, I found that not only are gas sensors expensive but most of them might not be suitable for outdoor use at all. Hence I have cut down on the sensors and added expansion connectors in my design for later use. The current design is shown in the figure below.

image

It has been a slow week due to personal reasons but I have come up with the above diagram and there are a few pieces still missing which I will add once information comes together.

 

Description

 

The system has three main parts. The first is the Field Sensor Node which is where a lot of the work is focused. It uses the 'compulsory parts' and I have received samples via Dr. Defeo. They are SMALL! The objective here is to create a booster pack for power management and an expansion board for the sensors. I will spend the next week working on board layout and will try and send that to manufacturing ASAP. This node talks to my second module which is the Beagle Bone Black over the CC110L which is a 433MHz based module and I am hoping to test out its range and performance. The BBB will have the CC1101 module which is a bit more feature rich and will itself talk to the Sierra Wireless Cloud. I have successfully tested the Sierra Air Vantage platform and will try to do a writeup next week.

 

The third module is the CC3200 based Table Top Sensor. I have used a Fuel Booster Pack from a previous roadtest and it seems with a little modification I can charge it up using a solar panel directly! More details will come soon. A small addon board here again for the sensors and the data is directly logged to Sierra Wireless. I have tested connectivity from the CC3200 to the Sierra Wireless platform and works like a breeze. The documentation is a bit slow on my part because I was unclear as to the usefulness of some things.

 

I am running some experiments on the CC3200 boards and will start writing more detailed posts when I am done.

 

More later.

 

Cheers,

IP

  • in reply to DAB

    The small pitch is something new but I am looking at the layout to get it right. Will update soon.

  • in reply to shabaz

    Shabaz sir,

    I have a similar view of the supercaps and will experiment before anything. Alternatively I am using a lithium ion battery from an old cellphone for storage.

    Have to get the PCBs out ASAP.

     

    If you writenaboutbyour experiments I would be very interested.

  • Very good post.

     

    I am really interested in seeing how you use the battery booster pack with solar collectors.

    I had a similar idea that I was hoping to get to.

     

    DAB

  • in reply to ipv1

    Awesome stuff!

    You might need 2 supercaps, because the recommended IC I think prefers a slightly higher voltage that the usual 2.5V or 2.7V or so that the large supercaps may be rated at (I think the IC prefers a higher voltage - I looked at a different ic in TI's range, not the recommended one), and so then perhaps a couple of them in series may be better (and zeners across each one possibly, to prevent them charging to a higher voltage).

    I also purchased a supercap from Farnell (I chose this one due to best balance between physical volume, capacitance and price) but I made the mistake of not reading the IC datasheet first and ordered just one : ( so now I need to purchase another.

    I still don't have the target circuit fully fleshed out, so it was a bit of an experimental purchase just to at least begin prototyping, and I may need to reselect.

  • in reply to shabaz

    Dear sir,

    I am working on the PCBs right now and will have em done soon. Unexpected delays due to personal issues may dissrupt work though.

    I am getting solar panels from eBay since the ones on element14 are a tad bit expensive . I am saving a part of the element14 budget for sensor procurement.

    Then panels may be small or may be a bit big depending on availability. I am also getting a supercap! Might use the panels on a base station and for the indoor station I just might go for inductive charging image

    Two major tasks are PCBs and implementing OTA firmware updates for the CC3200. Going to keep this design in control and more focused since the last one was all over the place.

     

    Hope it works.

    Ip