## 3 Materials and Method
### Standardized Remote Laboratory. An Example Based on Supercapacitor Power Bank
#### 3.2.1 System Description  
The supercapacitor power bank (item 1, Figures 6 and 7) is connected through a single-pole double-throw (SPDT) relay (item 2, Figures 6 and 7) to choose between the charging or discharging circuits.  
For the charging circuit, the supercapacitor power bank can be charged from a programmable power source (item 3, Figures 6 and 7), according to technical specifications, Table 2. A protection fuse is placed for the charging process (item 4, Figures 6 and 7) to avoid potential risks.  
For the discharging circuit, an electronic load (item 5, Figures 6 and 7) is used. The electronic load consists of a bank of 8 power resistors connected in parallel. Each resistor is driven by a relay.  
Figure 5: REOPEN ICT infrastructure standardization and collaborative network design.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Component** & **Parameter** & **Units** \\ \hline \multirow{4}{*}{Supercapacitor} & Capacity: 5000 F & \multirow{4}{*}{5} \\  & Surge voltage: 2.85 VDC & \\  & Operating voltage: 2.4 VDC & \\  & Max. Continuous current: 210 A & \\ \hline \multirow{4}{*}{Relay SPDT} & Max. Switching current: 80 A & \multirow{4}{*}{1} \\  & Max. Switching Voltage: 75 VDC & \\  & Rated voltage (VDC): 12 V & \\ \hline \multirow{4}{*}{Programmable power} & Input voltage: 220 VAC & \multirow{4}{*}{1} \\  & Output voltage: 0–30 VDC & \\  source & Output current: 0.1–100 A & \\ \cline{1-1}  & Output power: 3000 W & \\ \hline \multirow{2}{*}{Fuse} & Rated current: 100 A & \multirow{2}{*}{1} \\  & Rated voltage: 500 VAC & \\ \hline \multirow{2}{*}{Resistor power bank} & Resistance: 1 \(\Omega\) & \\  & Power rating on standard heatsink @25 \({}^{\circ}\)C: 200 W & \\ \hline \multirow{4}{*}{Relay module} & Normally open interface maximum load: 250 & \multirow{4}{*}{8} \\  & VAC/30 A; 30 VDC/30 A & \\ \cline{1-1}  & Trigger current: 3 mA & \\ \cline{1-1}  & Working voltage: 12 VDC & \\ \hline \multirow{4}{*}{Current sensor} & Primary nominal RMS current: 100 A & \multirow{4}{*}{1} \\  & Primary current, measuring range: 0,..., \(\pm\)150 A & \\ \cline{1-1}  & Secondary nominal RMS current: 50 mA & \\ \hline \multirow{4}{*}{Switching power supply} & Input voltage range: 88–264 VAC & \multirow{4}{*}{1} \\  & Output voltage: 12 VDC & \\ \cline{1-1}  & Output current range: 0–4.2 A & \\ \cline{1-1}  & Output rated power: 50.4 W & \\ \hline \multicolumn{2}{c}{Voltage sensor} & \multirow{4}{*}{Range: 0–12 VDC} & \multirow{4}{*}{1} \\ (implemented by resistor divisor) & & \\ \hline \hline \end{tabular}
\end{table}
Table 2: Supercapacitor power bank. Component specifications.  
Figure 6: Supercapacitor remote laboratory. Component layout.  
For the control and data acquisition system, an Arduino microcontroller (item 6, Figure 6) is used. The Arduino microcontroller is connected via a Universal Serial Bus (USB) interface to a local computer (item 7, Figure 6) and via the RS-232 protocol to a programmable power source. The student can visualize the laboratory physical plant in real time through a USB-connected video camera (item 8, Figure 6). Similarly, the information obtained by Arduino is displayed through a UI (item 9, Figure 6) at the user PC connected remotely. This user interface allows the student to interact with the real plant.  
The technical specifications of each component used in the supercapacitor test bench are shown in Table 2.  
The physical implementation of the supercapacitor power-bank-based remote laboratory is shown in Figure 8. The image on the left shows the charging process of the supercapacitor power bank, and the image on the right shows the process of the discharging cycle.  
For the charging and discharging tests, the operating conditions to be imposed for security and avoiding risk in remote mode are shown in Table 3.