Wuthering Bytes Sensor Workshop went really well. Thanks to all who attended and helped out on the side.

Above: Intrepid Paolo fixing a sensor in place

[Credit: @ghalfacree https://twitter.com/ghalfacree/status/501020206555484160]

Below: Chris Roberts’ excellent construction work. [Credit: @naxxfish https://twitter.com/naxxfish/status/500971732908666880]

Documentation Update

We Have Wiki

There’s a new Wiki at https://github.com/OxFloodNet/network/wiki which we’re using to collect unstructured information like system architecture, aims and guides.

Here’s a quick preview of the block diagram which explains the parts:

image

Parts List, Schematic and Gerbers

The PCB design files and a Bill of Materials are now on github which you can use to build your own sensors. The BoM is in Excel format at the moment, but we’ll try to keep things out of binary formats where possible. (PCB designs are EagleCAD format which must be binary.) 

Gateway Device still needs work

There is a lot to do on the gateway device github area. A generic base SD card image with the latest Node-RED would be a start. Any help appreciated. 

Feels like it’s coming together at last.

Workshop: Useful Information

On Sunday Ben and Andy will be running a workshop on Oxford Flood Network at Wuthering Bytes in Hebden Bridge.

If you’re thinking of joining this workshop here’s a little extra information for you. 

The Aim

Aside from the fun of participating in a citizen science project we want everyone to learn about deploying sensor networks - a critical part of the Internet of Things.

Oxford Flood Network is in the early days of development and we hope that bringing a number of volunteers together we can tap people’s skills to develop the overall flood network concept, making more flood networks possible with less trial and error.

What to Bring

Team 1 - Indoors - If you want to help assemble some sensors then please bring along

  • a soldering iron,
  • solder and
  • some side-cutters.

We’ll be experimenting with Node-RED and Raspberry Pi, so bring along:

  • Your Pi Model B and cables
  • a spare SD Card
  • A Ciseco Slice of Radio or SRF stick if you have one

Team 2 - Outdoors - We’ll be outside trying to find a suitable location for a sensor and doing some range testing before coming back indoors to help team 1.

Bring:

  • Some wellies or waders
  • (raincoat?) and
  • some ideas/tools for attaching a sensor to something.
  • Get in contact with oxfloodnet on Twitter if you have a step-ladder. (no point in doubling up)

So far we’ve experimented with these, so if you have any handy bring it along

  • velcro strips,
  • cable ties,
  • magnets and
  • Sugru.

We may just be able to use the decking of the town hall, or put the sensor under a bridge. The more inconspicuous the better.

A Word About The Sensor Devices

We’re bringing some sensor kits along and we’d love it if you could help with some basic assembly or soldering. Unfortunately due to the cost of the components you can’t take them home with you unless you can pay £140 each.

We’d like to be able to give something back to the community for having us at Hebden Bridge so we’ll be donating a sensor to the cause. If you want to crowdfund a second one then we’re all for that.

Yawn Health & Safety…

The outdoor team members will need to sign a disclaimer to make sure none of the organisers are liable for accidents. As you might expect we’re not able to guarantee your safety, but we want to keep things simple and avoid potential incidents.

  • If there’s heavy rain we may have to reconsider.
  • If we need to get into the stream it will be slippery (duh) so keep your wits about you and make sure you have a partner.
  • If we can attach from above there may be heights involved on bridges, so be sensible and don’t over-reach. It’s not worth it for a sensor.
  • There won’t be mains voltage in use outside and all equipment will operate at ~3-5v
  • Duck shit is likely

Fun!

After all that I will lighten up and remind you that this is meant to be a fun exploration of the challenges in building your own sensor networks.

I can’t wait!

Oxford (Hebden Bridge) Flood Network

On 15th-17th August we’ll be at Wuthering Bytes technology festival at Hebden Bridge where Ben & Andrew will be talking about and making the Oxford Flood Network. 

If you’ve never been before, Wuthering Bytes is held in the picturesque and quirky town of Hebden Bridge, Yorkshire. It’s a combination of a technology festival and the Open Source Hardware Camp, an annual event run by OSHUG (Open Source Hardware Users’ Group) and thoroughly recommended for meeting people whose desks are covered in dev boards and Raspberry Pis.

image

On Saturday Ben will be exploring citizen sensing and creating your own evidence for your own issues such as flooding, air quality or noise.

On Sunday 17th Ben & Andrew will be running a workshop, so bring your wellies and we’ll split into two teams - one installing the wireless sensors in useful locations around the town, the other linking these up to the Internet using Raspberry Pi, Node Red, MQTT and lots of other sexy Internet of Things technologies.

If you want more information about the project, have a look at http://oxfloodnet.co.uk/background or just get hacking on https://github.com/oxfloodnet 

See you there!

Ben & Andrew

Sensor v3 is Ready for Action

Since our first sensor back at Sushack in November 2013 we’ve learnt quite a lot about what works and what doesn’t work with a river sensor. Many of these lessons came from our test installation in Central Oxford.

It manifested in different ways but it’s fair to say moisture is our biggest enemy. The ultrasonic sensor was only rated for indoor use and when suspended above a stream would start reporting 22cm no matter what the actual water height was. Tests with a more expensive IP67 rated sensor have proved we can’t skimp on the transducer, but has put the cost up by £40 or so. 

Shortly after we discovered this issue the entire device went offline. Not all IP55 rated cases are made the same and water got into the device after some very heavy rainfall. We now have a sturdy case with a seal and sensible holes.

The other issue was RF reception. The sensor was attached to a large steel girder under a bridge and this blocked much of the precious transmitted signal. During heavy rain ironically we believe it suffered from “rain fade” where the signal is disrupted by rainfall. To this end Andrew has added an external antenna. Which makes it look sexier too if I’m honest.

image

Finally, Andrew has created some instructions on how to assemble the latest version from the custom PCB design and some off-the-shelf boxes.

If you want to order an assembled device (approx £140) or a kit then email info@love-hz.com and we’ll let you know when we can deliver them.

Links to more information added

Down the side of the page you might notice I’ve updated the links to explain some of the background. We’re active on Github (software & designs) and also Twitter (https://twitter.com/oxfloodnet).

There’s also a PDF (oxfloodnet-summary.pdf) which gives a full summary of the project. 

A wet sensor. It’s hard to tell if this is condensation, sideways rain, or drips from above, but this is where we learn the value of IP55 rated boxes. 
Sensor v3 will have a weatherproof enclosure (see IP code system) and also a weatherproof ultrasonic rangefinder. Luckily it seems sensor v2’s electronic hardware is still working after this soaking.

A wet sensor. It’s hard to tell if this is condensation, sideways rain, or drips from above, but this is where we learn the value of IP55 rated boxes. 

Sensor v3 will have a weatherproof enclosure (see IP code system) and also a weatherproof ultrasonic rangefinder. Luckily it seems sensor v2’s electronic hardware is still working after this soaking.

The innards of sensor v2, and a picture of Ben installing the sensor. The Internet of Things sometimes involves laying in duck shit.

Progress! Sensor v2 mounted

This weekend Andrew and I worked on getting the new sensor installed. 

Other improvements:

  • A custom PCB was designed and manufactured for this sensor
  • It uses a single 3.7v lithium polymer battery so needs no voltage regulators. 
  • It doesn’t have the massive battery drain I designed into the first one ;-)
  • It’s much smaller
  • There’s a Dallas DS18B20 temperature sensor which compensates for the velocity of sound in different temperatures (surprisingly it makes a difference of centimetres). This could also provide a unique ID for each device later. And of course a temperature reading
  • Code and some schematics available on a new github project: https://github.com/oxfloodnet

The mounting uses strong magnets to hold it in place instead of velcro strips, which is interesting, but not cheap. It has a piece of wire wrapped around it in case it becomes dislodged (we didn’t have any string). We need to work on the mounting but the priority was to get radio range and battery life tested. 

For now it’s still in situ and stable. It’s currently tweeting heavily to a private account but a visualisation should be available soon. The main aim at the moment is to produce a viable outdoor device and then bring in all the data. 

More updates coming soon.

Sensor version 2 mounted under bridge. 

Sensor version 2 mounted under bridge. 

Making a citizen-built flood detection network in Oxford, based on river levels, groundwater and local knowledge.

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