We love challenges at Solar MEMS, and this time we decided to tackle the proposal by Soltec, which we were able to win thanks to the work of our team. The challenge was to propose the development of a believable low cost irradiance sensor that could be integrated into a solar network. Our idea was to make one that could easily be coupled into a system of this nature, using our ISS technology, and which would cost less than €30 to manufacture.

Solar MEMS has a lot of experience in sun sensors and also in bespoke engineering solutions, so this innovation challenge was, to an extent, similar to what we often do for our clients: analyse their projects and requirements, then create effective solutions that can meet these requirements.

To do this we define 2 main stages; one in which we look for an idea that combines the technical requirements for the sensor  and another for lowering the costs so that the manufacture of the device does not cost more than €30.

Technology on which the idea is based

Our winning entry was built around an irradiance sensor that drew on the migration of space technology for solar sensors, as used in the satellites of dozens of our clients around the world, such as NASA, ESA, Airbus DS, Northrop Grumman, etc.

This technology relies on the use of four-quadrant photodiodes to detect the solar vector (angle of incidence of the sun’s rays). Solar MEMS uses this technology in its ISS (industrial sun sensors), which can also measure irradiance indirectly through photogeneration and the solar vector.

ISS technology uses a proprietary optical design by Solar MEMS which allows the solar vector and irradiance to be measured with an adaptable field of vision. This means the technology can adapt to the need for solar tracking: on one or two axes, spinning/elevation or azimuth/elevation, low precision (PV) or high precision (CPV) heliostats, etc.

How to lower costs to meet the requirements

The sensors that Solar MEMS currently sell, and on which the idea proposed for the Soltec challenge is based, cost more than the 30 euros to manufacture. Besides our idea, to satisfy the entry conditions, we needed a plan to lower these production costs, based on a review of all interfaces to minimize costs.

This task is something Solar MEMS has done before for solar tracking systems (with different technical specs than the one requested by Soltec), making the nanoISS (10 €/unit for big volumes) and for automotive applications to achieve a cost lower than 5€/unit for huge quantities.This idea was the outcome of teamwork by Solar MEMS and won for us the ANCES Open Innovation 2022 award convened by Soltec. It is totally viable for production and the report submitted with it includes the schedule and budget that would be necessary to make this sensor a reality.