Too much of a good thing can be a bad thing, and nitrate pollution due to agricultural fertilizer runoff is a major problem for both lakes and coastal waters. Assessing nitrate levels commercially is an expensive process that uses proprietary instruments and toxic reagents such as cadmium. But [Joshua Pearce] has recently developed an open-source photometer for nitrate field measurement that uses an enzyme from spinach and costs a mere $65USD to build.
The device itself is incredibly simple – a 3D printed enclosure houses an LED light source and a light sensor. The sample to be tested is mixed with a commercially available reagent kit based on the enzyme nitrate reductase, resulting in a characteristic color change proportional to the amount of nitrate present. The instrument reads the amount of light absorbed by the sample, and communicates the results to an Android device over a Bluetooth link.
Open-source instruments like this can really open up educational opportunities for STEM groups to get out into the real world and start making measurements that can make a difference. Not only can this enable citizen scientists and activists, but it also opens the door for getting farmers involved in controlling nitrate pollution at its source – knowing when a field has been fertilized enough can save a farmer unnecessary expense and reduce nitrate runoff.
There are a lot of other ways to put an open-source instrument like this to use in biohacking – photometery is a very common measuring modality in the life sciences, after all. We’ve seen similar instruments before, like a DIY spectrophotometer, or this 2015 Hackaday Prize entry medical tricorder with a built-in spectrophotometer. Still, for simplicity of build and potential impact, it’s hard to beat this instrument.
[Anirudh] and his friends were sitting around reminiscing about India. In particular, they recalled riding around in auto-rickshaws in stifling heat, watching their skin turn black from the exhaust. They started thinking about all of the soot and pollution in crowded cities the world over and wondered whether the stuff could be re-purposed for something like printer ink. That’s how they came up with their soot/pollution printer.
They created a soot-catching pump which they demonstrate with a burning candle. The pump mixes the soot particles with rubbing alcohol and an oil substrate and sends the ink to an HP C6602 inkjet cartridge. They used [Nicolas C Lewis]’s print head driver shield for Arduino to interface with the cartridge, turning it into a 96dpi printing head that uses only five pins.
[Anirudh] and his friends plan to design a carbon separator using charged plates to capture the soot particles from pollution sources and filter out dust. Be sure to check out their demonstration video after the jump.
Update: In response to [Hirudinea]’s comment about mining the carbon from cars, [Anirudh] is now looking for collaborators (tinkerers, filmmakers, DIY enthusiasts) to move forward with the idea of re-purposing carbon. Email him at firstname.lastname@example.org.
Continue reading “Here’s the Dirt on Printing With Pollution”
[Kasey] and [Guyzmo] have been working for the past couple of years on a side project that lets them monitor pollution using a network of sensors. They’ve just decided to make the project open source, both hardware and software. The details of the system are available at their GitHub repository.
There are two main components to the system. On the right is a base station which collects the data from the array of sensor, one of which is shown on the left. Each sensor runs off of a battery, but features a PV solar panel which keeps the power source topped off. It uses an Arduino to drive the system, and an XBee radio for communications. Some info about the sensors can be found on this summary page. There’s a PM10 particle pollution sensor, temperature, sound, nitrogen, and oxygen sensors. We also wonder if any data can be gleaned from how much electricity the solar panel is able to harvest?
The base station also uses an XBee radio to poll the network, but it’s not driven by an Arduino. They’ve gone with the ARM-based BeagleBone to manage the data.
You can have a lot of fun tinkering with the Raspberry Pi. But in addition to the low-cost hobby potential it is actually a great choice for serious data harvesting. This air quality monitor is a great example of that. The standalone package can be taped, screwed, bolted, or bungeed at the target location with a minimum of effort and will immediately start generating sample data.
The enclosure is a weather proof electrical box. The RPi board is easy to spot mounted to the base of the case. On the lid there is an 8 Ah battery meant to top off an iPhone. It works perfectly as it provides a USB port and enough current to operate the Pi. On top of that battery is a 3G modem used to access the data remotely — although it can log to the SD card for collection at a later time if you’d rather not mess with a cell network.
Look closely at the GPIO header and you’ll notice that an ADC add-on board has been plugged in. This is used to take the readings from the gas sensor which is monitoring for air pollutants in Paris.