This year’s edition of the technology and media conference, re:publica, in Berlin, Germany, hosted a rather unusual exhibit. Visitors gawked at a three-metre-high, four-legged bamboo structure, towering over bustling speaker stages and information booths. Those who took a closer look at the green structure, such as Germany’s Minister for Environment Steffi Lemke, were intrigued by two planting bowls full of vegetables at its feet, out of which small, black tubes snaked up towards a set of watering valves fixed to the bamboo construction. Those who let their gaze wander further upwards saw yet another tube, leading to a water tank, and next to it, a bunch of cables linking a battery, an open gray plastic box with a circuit board, and a solar panel. “What is this and what is it for?” was a frequent question, one that led curious visitors to discover an innovation ready to turn into a practical building block for many communities across the world.
So what is OSPIT and what is it for?
The Open Source Solar Powered Irrigation Tool (OSPIT) is a practical solution for small- and medium-scale agriculture projects that enables users to remotely monitor and optimise the efficient use of water, and thereby contribute to healthy and autonomous food production. What is more, the solar-charged battery and integrated Wi-Fi access point of the OSPIT also provide a technological basis for other local services and meaningful ways to connect to the internet, which can be designed and implemented by the local community.
The development of bamboo tower designs was supported by APC’s and Rhizomatica’s Local Networks initiative (LocNet) sub-grant programme for innovation and technology. LocNet also offered financial support for the development of OSPIT and its underlying solar charging technology, Open Maximum Power Point Tracker (OMPPT).
We interviewed the two women who developed the prototype: Elektra Wagenrad, a Berlin-based hacker and electronics engineer, and Pamela Cuadros, a designer and permaculture practitioner from Chile, currently living in the German capital. Edited excerpts:
What brought you together to create OSPIT? How did you manage to bridge the visions of labour-intensive, small-scale farming and the world of promising proofs of concept that never come close to a practical usage for non-tech-savvy people?
Wagenrad: We both had contributed to APC’s digital inclusion work before. I had designed a series of advanced solar charge controllers, called maximum power point trackers. To highlight the fact that the designs are open hardware and software, I named the series OpenMPPT. Their openness makes it possible for people with electronics skills to extend, modify, understand, reproduce and repair them. Following a request from Mike Jenson from APC, I also added support for environment sensors. At one point, Pamela and I started discussing the idea of extending the open hardware and software further for irrigation purposes.
Cuadros: I became aware of Elektra’s work at a workshop in Berlin, during one of those long COVIDwinters. Elektra showcased her OpenMPPT to a small group of persons in a sunny but cold co-working space. During this meeting, an early user talked about his experience using the OpenMPPT to charge mobile devices with solar energy on his balcony. I immediately thought: that could be used for the type of small crop planting I was doing in my backyard in Berlin. I saw the solar controller with its Wi-Fi abilities and sensors as an ideal basis to support people engaged in urban gardens and permaculture projects. A common issue is always how to water plants sufficiently, effectively and constantly. So I asked Elektra – who is, by the way, also involved in some gardening – if the solar controller could not be used for such kind of water management. Her answer was yes but she also warned me that it would take some effort. But I had sparked her interest. Shortly after that, she got back to me and we started to collaborate on a prototype.
There are many devices with time switches you can buy at a DIY store, which can also program to just open and close valves. Why should people care for an OSPIT instead?
Wagenrad: The idea is to be energy-autonomous and to grow plants as efficiently as possible, particularly in dry areas where water is precious and rare. Drip irrigation at early dawn is optimal for saving water, taking into consideration the effect of irrigating at the right time of day. Yes, one can buy a battery-powered timer valve to control a water tap that is fed by a communal or commercial water supply network and which offers plenty of water. The obvious trade-off of this primitive approach is that a fixed amount of water is used for irrigation every day, regardless of the soil being wet or dry, because there are no humidity sensors to monitor what is going on and no logic to take care of it. And you need an existing infrastructure plus the attitude to not care too much about wasting resources. If there is plenty of water in your area, this may be fine, but one might damage the plants by watering them too much and encouraging fungi that harm the plants. Our tank gauge also measures and reports the amount of water available in storage and allows remote monitoring via standard telemetry protocols. With solar power, we can also source ground water by using a pump to provide running water pressure. The solar power data gives us an idea about the sun irradiance and the sensor reports the temperature. We can also open windows of a greenhouse if it gets too hot inside.
Cuadros: I think you forgot an important point, Elektra – our approach is completely open-source. It is an open project that can be tweaked, and which others can contribute to. We are not interested in turning this into a closed platform and then sell fancy add-ons. OSPIT is an open technology; if something breaks, it is possible to identify the problem and fix it. From a permaculture perspective, OSPIT is more sensitive than a static irrigation system. Its sensors help analyse and monitor the environment and better understand the hydric needs of a specific plant. That can be the beginning of an interesting dialogue...
Many advanced irrigation devices combine single-board computers like Raspberry Pi and micro-controllers like Arduino to achieve similar functions. How do you manage to do more with less components?
Wagenrad: We have an open-hardware and open-source solar charger with maximum power point tracking that includes a relatively powerful and yet very cheap micro-controller. The micro-controller can connect to a wireless network, control the solar charge process with maximum power point tracking, and provide telemetry data – locally or globally – at the same time. Adding sensors [related to] humidity, tank gauge, temperature and controlling valves or pumps or motors that open and close windows according to the irrigation programme doesn’t put much additional load on it. So we don’t need another computer for it. A single OSPIT electronic device can handle this part.
Cuadros: Yes, it is sound [strategy] to avoid over-technologising food production. In the end, all components have a life span and can turn into tomorrow’s e-waste. We also wanted to keep it simple and by no way create a distance between, let’s say urban farmers and the raised beds or community gardens they are cultivating. Our idea was, just provide additional tools that help them optimise the use of resources like efficient water usage and solar energy for healthy crops.
The current functions of OSPIT could be further extended, based on needs and visions from local communities. Has any wish list been shared with you or [are there] specific use cases you want to explore?
Wagenrad: We have not yet developed actuators for opening and closing the windows of a greenhouse because the current installation is outdoors. This could be a useful addition. Another sensor option could measure acidity of the soil…
Cuadros: ...or the pH of the water, because this way you could know immediately if the water is contaminated and whether it is safe for humans and plants. Imagine if the water source is a river where the pH level changes from one day to another – that would be a clear indicator of a disruptive event in the ecosystem.
An important agent of digital inclusion are community networks. Why and how do you see OSPIT as an alternative, especially for this user group?
Cuadros: Well, to talk about alternatives, we first have to ask, what kind of irrigation devices communities currently use, if at all. We do not want to push OSPIT on people, but if a community is involved in food production or wants to start to grow food locally, it would be worthwhile to evaluate and eventually design a use case together. I think an interesting feature of OSPIT is its possibility to function as an open Wi-Fi access point for individual users, while also supporting water management. Just imagine an urban garden where people gather to connect to the internet in the green shade of the trees and, at the same time, this solar-powered device discretely helps to harvest big tomatoes...
During re:publica, you made visible all the components of OSPIT, so that people can see more then just a black box for plug and play. However, usability will be an issue to make the device popular. What is important to make OSPIT a really inclusive technology?
Wagenrad: To make OSPIT more accessible, the next step is to make and publish an open-hardware design, extend the open software and provide a practical manual. PCBs (printed circuit boards) and kits can be made available – and people can order PCBs on their own from manufacturers using the published design and start a local production to put everything together. It can also be sold as a product, if someone [gets into the business].
Cuadros: I think it would be interesting to co-design irrigation solutions directly with local communities and provide guided and participatory installations. I also think we should improve the graphical user interface because some people might not be able to make certain changes or updates using the console. We also have to ensure that people with older hardware or operating systems can access and control OSPIT. And echoing what Elektra said, a comprehensive user manual is super important.
OSPIT is not yet available in a hardware store, and probably that is not your vision either. But for those who are curious to test it or to contribute to the future development, how can they get in touch?
Wagenrad: The idea is to develop and publish the open-hardware and open-software solutions together with a guide explaining all the options, advantages and disadvantages. If you have questions, contact me at onelektra@gmx.net or Pamela pameluza@gmail.com.
Let me add one more comment on openness and sustainability. Over the last three decades, I have collected experiences with several closed source hardware solar controllers in our community. When closed source hardware breaks after the warranty has expired, people ask me to fix it. The typical “consumer” with higher income simply throws away broken hardware and buys anew. Without access to the schematic and sometimes with even identifying labels on the crucial internal integrated parts deliberately removed, the effort of repairing such closed source hardware and/or buggy/broken firmware is not feasible, as it requires intense reverse engineering hardly anyone can and is willing to pay for. Some people seem to believe that producing piles of electronic waste is much better for the economy.