The team at C⁴Derpillar have set these goals for the 2015 Hackaday Prize:
- Develop an open-source Capillary Electrophoresis (CE) Capacitively-Coupled Contactless Conductivity Detection (C⁴D) platform for under USD $500.
- Demonstrate the effectiveness of the platform by developing an affordable water testing unit capable of taking automated measurements of nutrient levels in a water system.
- Effectively communicate our use of open-source technology and academic research to contribute back to the open community and establish a public global monitoring network.
As of 22/9/2015, we have received and assembled the exciter and detector PCBs and are in the process of prototyping the plumbing of the system in order to conduct a trial separation!
So far we've written code to control our programmable function generator and have tested our voltage amplifier circuitry. We have also written code that lets us run various 'diagnostics' over serial such as dumping the output from the ADC and resetting the device.
Using a digital potentiometer to control the excitation voltage is proving problematic as we could not even get it to show on the I2C bus! At the moment, we are using a fixed resistor to yield ~50V as the excitation signal.
Our next task is to diagnose a fault within our solid state relays (they won't turn on so we can't do a trial separation!) and start characterising the output signal from the system (noise floor of the signal, standard error, SNR). Fortunately, the detection circuitry (the meat of the whole project) appears to be operating within parameters, so all we need to do now is push some liquid down a tube - something that proved elusive all of Sunday night :(
After this is taken care of, it's time to put the unit into appropriate housing (so that it is portable), start developing a nicer user interface (cloud data storage and administration) and conduct a shedload of tests on the device.
At the moment, the project looks like it will stay within budget (more details to come in detailed costings).
Below is our short video for the Semifinal round, showing some hyperlapses of us building various parts of the system. Stay tuned for the next instalment, which will feature a full Electrophoretic separation of river water and finally demonstrate just how innovative our device is!
What problem are we solving?
The United Nations Secretary General Ban Ki-moon states that every year, more people are killed by unsafe water, than all forms of violence, including war. It is thought that the primary source of water pollution is inadequately managed industrial and agricultural waste. This disproportionately affects developing countries, which are industry-rich but lack the resources to effectively police strict environmental regulations.
The Executive Director of the United Nations Environmental Programme concedes that the lack of resources for monitoring and assessment make it difficult to obtain a global picture of water quality. Whilst the technology exists to analyse chemical levels in water, these processes suffer from significant limitations. Traditional techniques, such as ICP-AES and ICP-MS use expensive (USD $50, 000 - $0.5mil), complex machines that require the supervision of an expert operator. These operational requirements make it impossible to obtain regular readings over a wide range of remote monitoring sites, limiting the conclusions we can draw from water quality data.
The same publication laments that traditional methods lack the spatial and temporal resolution to draw effective conclusions regarding water quality. This information gap is not only an issue in developing countries, as the Animas river incident of August, 2015 has shown us. An accidental spill of from an abandoned mine by the US Environmental Protection Agency led to the release of 3 million gallons of industrial waste which affected 3 states. The EPA was criticised for delaying the release of an analysis conducted on the water while confusion existed in...Read more »