## 3 Results and Discussion
### Short- and Long-Term Tests  
Figure 9 shows the results of short-term tests run to demonstrate that the chamber works as expected. Test 1 (Figure 9a,b) consisted of the following stages: (1) stage 1--the barometric pressure was gradually increased to 945 hPa in 10 min; (2) stage 2--a pressure of 945 hPa was maintained for 10 min; (3) stage 3--the barometric pressure was gradually increased to 955 hPa in 60 min; (4) stage 4--a pressure of 955 hPa was maintained for 10 min. Test 2 (Figure 9c,d) consisted of the following stages: (1) stage 1--the barometric pressure was gradually decreased to 935 hPa in 10 min; (2) stage 2--a pressure of 935 hPa was maintained for 10 min; (3) stage 3--the barometric pressure was gradually decreased to 925 hPa in 60 min; (4) stage 4--a pressure of 925 hPa was maintained for 10 min. Figure 10 shows the results of long-term tests run to demonstrate that the chamber works as expected. Test 3 (Figure 10a,b) consisted of the following stages: (1) stage 1--the barometric pressure was gradually increased to 945 hPa in 60 min; (2) stage 2--a pressure  
Figure 9: Results of short-term tests run to demonstrate that the chamber works as expected: (**a**) test 1—control signal fluctuations while controlling the pressure valve; (**b**) test 1—rising pressure within the barometric chamber; (**c**) test 2—control signal fluctuations while controlling the vacuum valve; (**d**) test 2—decreasing pressure within the barometric chamber. of 945 hPa was maintained for 20 min; (3) stage 3--the barometric pressure was gradually increased to 955 hPa in 180 min; (4) stage 4--a pressure of 955 hPa was maintained for 20 min. Test 4 (Figure 10c,d) consisted of the following stages: (1) stage 1--the barometric pressure was gradually decreased to 935 hPa in 60 min; (2) stage 2--a pressure of 935 hPa was maintained for 20 min; (3) stage 3--the barometric pressure was gradually decreased to 925 hPa in 180 min; (4) stage 4--a pressure of 925 hPa was maintained for 20 min. The control signal applied to the valves ranges from 0 to 1023 (10-bit value). Experimentally, we observed that values from 0 to 450 correspond to a dead band in which there is no pressure response inside the chamber. Hence, minimum values of the control signal were set in 450 to achieve a faster response while controlling pressure. The barometric pressure results obtained in the short-term and long-term experiments (Figures 9 and 10) demonstrate that the control system operated properly, complying with the setpoint values and with the specifications for rise/fall time. The results from test stages 1 and 3 (i.e., ramps) indicated linearity while varying the barometric pressure. The linear function in the ramp stages was chosen by the entomology team as a good way to simulate real fluctuations, but other mathematical models could be implemented to change pressure in these stages. Likewise, the experiments comprise four stages due to the requirements specified  
Figure 10: Results of long-term tests run to demonstrate that the chamber works as expected: (**a**) test 3—control signal fluctuations while controlling the pressure valve; (**b**) test 3—rising pressure within the barometric chamber; (**c**) test 4—control signal fluctuations while controlling the vacuum valve; (**d**) test 4—decreasing pressure within the barometric chamber. by the entomology team, but other strategies/methodologies could be implemented in the algorithm. Table 1 shows descriptive statistics of the stages of the steady setpoint (i.e., stages 2 and 4) for both short- and long-term tests (Figures 9 and 10). The average matched the setpoint values in all tests. The maximum deviation from the average was 0.1 hPa; hence we can specify that the chamber control system is able to assure pressure stability of \(\pm\)0.1 hPa from the setpoint value. [PERSON] et al. [24] designed a barometric chamber in which the maximum difference between the instantaneous setpoint pressure and the recorded pressure was 1.1 hPa.