About Us

Rainbow sensing co-designs, creates affordable, open and locally sustainable devices and software solutions to measure, monitor and understand complex environmental processes. We equip local people with local devices and open knowledge so that they can monitor and understand their own environment. More: We adhere to the Principles for Digital Development. Examples include our work with TAHMO on OpenRiverCam, an open source web platform for river flow monitoring with CCTV cameras, OpenDroneMap360, an affordable high quality 360-degree camera solution specifically designed for creation of 3D reconstructions in complex environments, and OpenCadaster, a long-term project to establish a GPS base station network accross Africa and a user-friendly smartphone hard- and software solution for cm precise surveys. We continuously seek R&D funds to support our new innovations, and offer our service to businesses that require a sustainable and affordable data collection, to train local service providers to start using our tools.

Our team

Our team consists of international specialists in environmental sensing and data including geospatial, hydrology and imaging. All our team members have affiliation with electronics, and software development. Our combination of skills leads to what we are, a social enterprise for the development, piloting and roll out of products and services for environmental monitoring in any country or city in the world without the constraints of proprietary solutions. We don’t sell our products, we don’t profit from them, instead we facilitate their use through training and scaling activities.

Hessel Winsemius


Hessel is trained as hydrologist. Within Deltares, he gained 15 years of experience with flood and drought risk datasets and modelling, and flood and drought monitoring and forecasting. His approach to design of technology and projects is strongly anchored in co-design. Over the past 5 years, his focus has been on research and development of locally sustainable technology for data related to natural hazard risks, and creating a bridge between local entrepreneurs with skills to collect data sets, and international audiences, that require such data sets, such as water-related consultancy. Within Rainbow Sensing, He conceived the idea for OpenRiverCam, the first entirely free and open-source suite for operational management of river monitoring sites using camera observations. Within Delft, University, he supervises students that work on affordable or repurposed technology for environmental monitoring. 

Ivan Gayton

Humanitarian innovator

Ivan has over 15 years experience leading cutting-edge development and deployment of open source mapping and drone technologies for humanitarian aid. He has been Head of Mission, GIS and Technical Advisor for Médecins Sans Frontièrs / Doctors Without Borders in numerous countries including Nigeria, Haiti, Libya, and South Sudan. Ivan conceived and co-founded the Missing Maps project (missingmaps.org) in 2014 in response to the West Africa Ebola outbreak; conceived and developed MapSwipe a software for crowdsourced off-line mobile image classification for humanitarian mapping. He also led a collaboration between MSF and Google to create electronic medical records in Ebola centres (projectbuendia.org). Ivan continues to manage and/or support a suite of community mapping and tech initiatives in approximately 10 countries as part of the Humanitarian OpenStreetMap team and Rainbow Sensing. 

Iddy Chazua

Use case developer

Iddy is the Use case development officer based in Dar es salaam, Tanzania.  He gained a lot of experience in working with data and community from HOT and OpenMap Development Tanzania (OMDTZ) where he works as GIS&Tech lead.  Mr Iddy has an expertise in various geospatial technologies, and is capable of data analysis and visualization, data management, and has facilitated training and workshops with several government agencies and NGOs.

Frederick Mbuya

service developer

As CEO of Uhuru Labs, Frederick Mbuya creates and rolls out innovative and local technology for environmental monitoring. He creates value-added datasets with locally deployable drones, rolls out and maintains hardware and software stacks for local use cases, and has a passion for Free and Open-Source. Freddie’s experience in Tanzania, and other African countries make our innovations truly sitting in the countries that they are built for.