Merga Assefa, a PhD student of Jimma University, uses the SPSA in his research. He measures PM2.5 at local alcohol producers in a town in western Ethiopia. Afework Tademe, my colleague from Electrical Engineering, built ten sensor systems last June. Of the total ten, he would use four instruments to collocate multiple SPSA, for evaluation of intra-correlation. Merga also loaned my three UPAS instruments, to conduct validation measurements with the gravimetric method. My personal interest is to gain more data on the quality of the SPSA. For that reason, Merga only paid a construction fee of 500 ETB per piece for six SPSA. He took the additional four SPSA and three UPAS for my data interest and therefore free of charge. In this way, a PhD student accessed measurement instruments for some months, for total costs of only 3000 ETB (30 euro).
(Non-)user friendliness of the SPSA
This was the first time someone from outside Arba Minch University used sensor systems constructed by us in Arba Minch. Both Merga and I miscalculated the required time for instructions. Merga left Arba Minch soon after receiving the sensor systems. Only in the field he realized the questions he would have liked to ask in Arba Minch. The SPSA has no user-friendly screen and buttons, no vandal-proof 3D-printed encasing, and no user manual. For measurements under my direct supervision, I quickly recognize and resolve potential errors. Afework conducts small repairs on the spot. For Merga, it was the first time working with measurement instruments, under conditions with (almost) no availability of electricity, and far from Afework and me. This resulted in some SPSA becoming unusable during Merga’s measurement period, and some data loss.
Upon Merga’s return I certainly took some lessons in what additional instructions are required, and what hardware and software changes can be made to the SPSA to make it better usable for non-experienced users. However, I give a strong preference for a low-cost instrument that forces the user to think on its feet, and gain experience from trial and error, over an expensive, over-developed black-box instrument that works but keeps all experience for the developer alone. In my opinion, the Ethiopian research community is served better by requiring them to find things out for themselves (say learn by doing), than by large funds supplying expensive full solutions.
And, despite the challenges, Merga collected some 350 hours of 10-second PM2.5 data. Possibly, this could have been double if he would have had ten commercial sensors. I leave it up to the reader to decide what is better: 350 hours for 30 euro, or 1,000 hours for 2000-3000 euro?