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The project's funding goal was not reached on Mon, October 31 2016 8:32 AM UTC +00:00
S.H.E.NBy S.H.E.N
First created
S.H.E.NBy S.H.E.N
First created
£1,071
pledged of £3,000pledged of £3,000 goal
28
backers
0seconds to go
Funding Unsuccessful
The project's funding goal was not reached on Mon, October 31 2016 8:32 AM UTC +00:00

About

Why create an arsenic detector? 

Water networks are often destroyed in conflict zones and by natural disasters. In such circumstances groundwater must be relied upon for drinking water. However groundwater can be contaminated by arsenic, which is poisonous. We want to create a low-cost open-source arsenic detector so it can be used to identify whether water in local groundwater supplies are safe to drink. 

UNHCR refugee camp
UNHCR refugee camp

Who are we?

We are a group of students from Tsinghua university and University College London. Our skills are diverse. We are designers, mechanical engineers, chemists, physicists, environmental scientists and programmers. Most importantly we are passionate and enthusiastic about making a difference and doing it sustainably.

We met on a summer school sponsored by the University of Geneva, Tsinghua university, University College London and the Lego Foundation in July 2016.

Here are some pictures

Top row left to right: Anuradha Vibhakar, Meng Chao, Gavin Leong, Li Jaiwei. Bottom row left to right: Tian Yibo, Gao Jiasi, Hashim Dangra, Lingzhi Chu.
Top row left to right: Anuradha Vibhakar, Meng Chao, Gavin Leong, Li Jaiwei. Bottom row left to right: Tian Yibo, Gao Jiasi, Hashim Dangra, Lingzhi Chu.

 

The design process

We had two sets of constraints by which we had to create the design.

This project was put forward by the International Committee for the Red Cross (ICRC) and they recommended the following: 

  • low cost, approx. $1 per test 
  • something that can be rapidly deployed in the field 
  • with a human centred design 
  • can be plugged into a phone 
  • would need to be easy to use, by non trained specialists 
Sketch of the arsenic detection techniques
Sketch of the arsenic detection techniques

After researching various different arsenic detection methods we chose to use a chemical technique. A report detailing the arsenic detection techniques we considered is given here:

https://1drv.ms/b/s!Al_45DUz7wQzaxzknaBhZbrOJxo

This imposed certain conditions on the design: 

  • the paper strip could not be exposed to sunlight
  • the reagents and water sample container would need to be disposable and only have a one time use
  • the arsine would need to travel to the paper strip coated in mercury bromide 

Some of our initial sketches:

Initial sketches of the detector
Initial sketches of the detector

 SHENDY: the arsenic detector

 

The water sample is poured into the device. Subsequently the chemical reagents are fitted into the base and the device is fitted together. A button is pushed so that the reagents are released into the water sample and the following chemical reaction takes place.

As2O3 (aq) + 6Zn(s) + 12HCl(aq) −−→ 2AsH3 (g)+6ZnCl(s)+3H2O (aq)

The arsine gas that is produced from the chemical reaction travels up to a paper strip. The paper strip is coated in mercury bromide.

This results in one of the following two reactions:

AsH3 + HgBr2 −−→ AsH(HgBr2)2 (yellow)

AsH3 + HgBr2 −−→ As(HgBr)3 (brown)

Each concentration of arsenic produces a different shade of colour between yellow and brown. The colour on the strip of paper can be quantified and can be calibrated to represent a particular concentration of arsenic. This is achieved using a colour light to frequency converter connected to an arduino nano. 

The saturation value of the colour on the strip is determined and this information can be transferred to a phone.

Schematic of arduino nano
Schematic of arduino nano

 

Calibrating arsenic concentration
Calibrating arsenic concentration

 

Why S.H.E.N? 

Shen means arsenic in Mandarin. We think the name is cool, represents that 6/8 of us are Chinese and that we did most of this when in China. 

Does it work? 

Half of the detector works. We know this because we made it and tested it. We know that the if we are able to change the colour of the detection strip then we can determine the concentration of arsenic. Here are some photos of this: 

Shenzhen open innovation lab open day: demonstrating our detector to the public
Shenzhen open innovation lab open day: demonstrating our detector to the public

 

Shenzhen open innovation lab open day: Graph on the mac is the output from the arduino
Shenzhen open innovation lab open day: Graph on the mac is the output from the arduino

 

Detector at the centre of the table is the working model, white and green in colour with wires sticking out
Detector at the centre of the table is the working model, white and green in colour with wires sticking out

Why do we need the funding? 

We need to test whether the chemistry works. To do this we need to buy chemicals, which are expensive (it costs £56 to buy 250g of arsenic). We also want to determine whether the chemistry can be performed on a microscale using microfluidics, which could significantly decrease the cost of the detector. We need to establish a method of waste disposal that can be completed in an environmentally friendly way or by turning the products of our chemical reactions into harmless chemicals that can be disposed of in the environment. Once we have established the chemistry we wish to make some prototype detectors.

Are we unique? 

There are a few teams that are working to build an arsenic detector, using different techniques. Their methods are patented, take 5 hours to complete whilst ours is open source and takes minutes to complete. Some are companies who wish to make a lot of money. We are doing this as a non-profit and creating something that we want anyone in the world to be able to create and use. 

We are also making an app to map the arsenic concentrations in water around the world. By purchasing a detector you can interact with your local environment by recording the arsenic concentration in local water supplies and upload this data to the app.

Once we have the product we are very well placed to be able to manufacture and distribute. We met with many companies in Shenzhen and know of a few programs that can accelerate the making of our product once it has been fully designed and prototyped. 

Here are the organisations that have been helping us so far:  

Once our product has been manufactured we believe we have access to the infrastructure (through the UN and our international mentors such as the ICRC) that could place the product in the hands of those who need to use it. 

This is how we picture it could work:

We think we can make this work, we are determined to. We accomplished all of this in two weeks. We think we can achieve a lot more in the next year with a little funding. And when we do make it work we are going to publish all our work, freely available so that everyone has the knowledge to make an arsenic detector.  

 

Risks and challenges

1. Getting the chemistry correct. We have access to chemistry labs and a wealth of chemical knowledge at our universities. We are certain that if we get stuck there will be someone here to help us move this project forward. Sharing the idea with a few friends has already generated a lot of ideas about different chemical techniques that could work. And even suggestions about how to trap the arsenic and purify the water.

2. Making it low cost. This is going to be tricky but we think with links to the global manufacturing hub of Shenzhen, we have a very good opportunity of minimising the cost.

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    On our website there will be a page dedicated to showcasing all the support we hope to obtain in getting our project started. We wish to feature a photo (or a name if you prefer) of every individual that has contributed.

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    In addition to featuring your photo on our website, get a sticker to put onto your belongings. This will tell the world that you are enabling people in refugee camps to have access to safe drinking water.

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    Detector + sticker + photo

    Get a working detector that you can use to test the concentration of arsenic in water.

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    Name on instruction leaflet + detector

    In addition to receiving a special limited edition detector, your name will be printed alongside the instructions of how to use the detector that will be deployed in the field. Your name will be one of fifty.

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Funding period

- (30 days)