Overall System Design Specification

[TerryJC]

We made good progress on the inter-barrel plumbing today and should complete it sufficient for preliminary leak testing on Thursday. Testing at full load will need to wait for the welded joints to go off completely, 24hrs recommended. I planned to put in 2 vertical pipes, fed from the bottom of barrel interlinking pipe, so we can conduct 2 depth measuring trials simultaneously. Is that going to be enough?

That's what we had in mind for the installation (eg one linear one fallback sensor) so I don't see why not.

I would appreciate a chance to review the design specification face to face, would that be possible on Tuesday 30th at WMT at say 11:30

That will be a bit late for me. I have to set off to Bournemouth by 12:45, having had lunch. The latest I could leave on that day is therefore 12 noon. Could we make it a bit earlier or do it a different day?

[TerryJC]

All,

I have just posted Issue 0.2 of the River System Design Specification to the Development Website (see http://www.hadrian-way.co.uk/WMT_River_ ... ss_0.2.odt). Please review and comment on it.

I have just uploaded Issue 0.2.1 with Penri's comments to the Development Website. I have also uploaded Penri's Capacitive Measurement paper and his recent table of results.

With reference to Penri's comments, we can and will obviously discuss them when we get together next week. However, I'd like to include my initial responses now.

1. Illustration 1 Comment:

   I’m not in agreement with the architecture shown in this diagram, it need discussion.

   I agree. However, it wasn't meant to be an architecture diagram; it simply shows the best guess at the layout (from Clive's drawing) based on the little we have decided so far. I did say in the preceding paragraph that the drawing would be updated as the project progressed.
   As far as an architecture drawing is concerned, we can only do a very high level thing at the moment, because the architecture will to some extent depend on the layout we decide. For example, will the Master Pi be driving the pump(s) and directly interfacing to any sensors? Will any of the Remote Pi's be driving any pumps?
2. Section 3.2 Comment:

   Perhaps a moot point here but I see / saw the primary purpose of the buttts as reducing the burden of the river on the mains supply with irrigation as a secondary aim, I’d like to discuss before accepting.

   Perhaps the paragraph is a bit sparse, but I wasn't actually describing the purpose of the butts here. I was trying to describe how the water would be moved to and from the river.
3. Section 4.1.1.3.1 Comment:
   

   I’m sure that I’m being a little picky here but I think there’s a place for simple sensors here, particularly at max and min (failsafe) extremes. If all else fails this is what happens … Plus other potential level sensors should not be discounted at this point.

   Again I don't disagree with your comment, but I did say when I posted that I was only including devices that we thought might be viable at the time I wrote the document. Your work on the capacitive probe was inconclusive at that time.
   
   I did include a fallback probe in the next section.

[Penri]

Hello All

Hamish made good progress today, the initial leak test appeared to go well, we should be able to conduct further trials next week. I note your comment in regard tothe Tuesday meeting, Terry, and ask if you, Hamish and Clive (if available) would be happy to move the meeting to Thursday at 10:30?

Hwyl

Penri

[TerryJC]

Thursday at 10:30 is fine by me.

[Penri]

Hello All

In advance of tomorrow's meeting I've added some more input into the Design Specification for us to discuss, I'll explain the proposed changes as we go through the document and we can decide to keep, amend or ditch. Document attached herewith.

I've also attached a photograph of the little test circuit that's been put together for you, Hamish, so you can test your frequency measurement code for the capacitive probe. Also on the vero board is a Hall effect sensor and buffering circuit, I'll bring along a magnet on a disk to so see what you can do with it, code-wise.


See you tomorrow, hwyl

Penri

[TerryJC]

All,

I've uploaded Penri's version and a copy of the photo to the development server for posterity. I renamed the photo 'Test_Circuit.jpg' and it can be found in the '/Design/Drawings' folder.

[hamishmb]

Okay, I have hopefully sorted my email notifications out now

I have created the Progress forum too, and will make a start on learning Flask and getting the test program done

Hamish

[hamishmb]

Hi,

I have written a small application to test Penri's capacitive sensor, and it is attached here. I seem to get ~790Hz from the test board, is that correct?

Even though I have my Pi running at 100% CPU all the time it works fine, see the comments in the code for more details.

Terry, would you mind peer-reviewing this for me please? I know it's a bit messy, but I'm thinking about releasing it as an easy way to measure frequency of a signal for people who are new to RPi.GPIO, like me XD

Penri, to learn how to run the program, run it with the "-h" option. Let me know if you want some examples

Hamish

[Penri]

Hello All

Thanks for the meeting today, I found it very helpful. I’ve attached the modified layout document herewith, can you please check through it for me to see if you think the document is consistent with itself and the diagram used in the design spec. is good enough.


Thanks

Penri

[Penri]

Hamish

The 790Hz you are measuring is there or thereabouts as far as I'm concerned, we can check performance against another measuring instrument at some point.

Now you have the ability to measure frequency when do you think you will be in a position to deploy a version that we can use to start monitoring water level, plus recording and storing results every say 10 minutes?
Also, and this question is for Terry too, what will be need to make it happen? I can provide capacitance probe, interface circuit & power supply brick plus rudimentary weather shelter, what else do we need?

Should this conversation be on the progress forum?