The measurement of environmental variables turns out to be a wide field in which different techniques are used to capture the desired analog signals, all of the above in order to transform them and deliver them in such a way that their interpretation is clear. This article describes a research project, which was carried out for the Institute of Hydrology, Meteorology and Environmental Studies IDEAM –Colombia–, where a reverse engineering methodology was implemented aimed at the application of proprietary technologies to generate a new device capable of measuring soil temperature and moisture, starting from the design of the electronic circuit and arriving at the simulation. All based on existing equipment for the identification of electronic components, performance curves, and input and output signals, this with the aim of conceptualizing and generating bases for the final design.

Aquaponics are defined as hydroponic crops merged with recirculating aquaculture systems and bacteria, achieving a synergic relationship that takes fish wastewater and uses it in order to grow plants, then the last one in association with nitrifying bacteria are used as a natural filter that removes dissolved nitrogen, ammonia, among others, controlling the fish waste accumulation. Nowadays there are different research areas in aquaponics, from ones focused on the applied techniques in aquaculture and hydroponic sub-systems; through applied sciences such as modeling from both physical and chemical systems; arriving to the types of aquaponics, qualified from technification grades; concluding with fish and plant crop species and their interaction. In this paper a systematic review is carried out in order to observe the research current state in automated, technified and traditional aquaculture systems, thus having a sight of the investigative orientation in this field. This review is based on scientific papers from four databases, taken in March of 2020, obtaining 1356 results, evaluated and filtered for further analysis. From the review it was found that there is an exponential quantity growth in papers per year, moreover, it is noted that the paper fields of greatest concentration are aquaculture, agriculture, environment, water analysis, horticulture and electronics, the most worked species are lettuce (Lactuca sativa) in hydroponic NFT and tilapia (Oreochromis niloticus) in single recirculating aquaponic systems (SRAPS). With the obtained data it was built a diagram that consolidates current research branches in aquaponics.

Crops are vulnerable to climatic conditions; therefore, their quality may vary according to environmental behavior. Under optimal conditions the crop can have a good productive development and an increase in the yield per unit area, reducing the risks caused by climatic changes, pests and diseases. With the electronic application in greenhouses it is possible to make efficient use of the resources since these can be controlled according to each stage of the development of the crop. Being in an isolated environment, in other words, independent of the external environment, it is possible to carry out production at any time of the year, thanks to the microclimates.  The following paper shows the development of an automated greenhouse using electronic instrumentation to control its irrigation, lighting, humidification and ventilation systems using fuzzy logic.