## 3 Results and Discussion
### Electrochemical and Photoelectrochemical Experiment Characteristics  
#### 3.2.1 Electrochemical Experiments  
Figure 7 presents the results of the EC measurements using a \(K_{3}Fe(CN)_{6}/K_{4}Fe(CN)_{6}\) solution in 0.1 M \(KCl\). Data from our system (red line, red data points) are compared to a reference commercial device (black line, black data points). Figure 7a depicts cyclic voltammograms for 10 mM \(K_{3}Fe(CN)_{6}/K_{4}Fe(CN)_{6}\), with the anodic peak current (i\({}_{\text{pa}}\)) used for evaluation. Figure 7b shows chronoamperograms for 1 mM \(K_{3}Fe(CN)_{6}/K_{4}Fe(CN)_{6}\), where the difference in current density between the pre-pulse and steady-state current serves as the evaluation metric. The EC measurements demonstrate consistent results between the two devices, with minor deviations observed at some concentrations.  
The couple of the ferricyanide ion (\(Fe(CN)_{6}^{3-}\)) and ferrocyanide ion (\(Fe(CN)_{6}^{4-}\)) serves as a well-defined redox system in these electrochemical experiments. The reaction depicted in Equation (1) represents the reversible reduction of \(Fe(CN)_{6}^{3-}\) to \(Fe(CN)_{6}^{4-}\) (forward reaction) and the corresponding oxidation process (reserve reaction).  
\[Fe(CN)_{6}^{3-}+e^{-}\rightleftarrows Fe(CN)_{6}^{4-} \tag{1}\]  
The CV experiment offers a valuable tool to probe the electrochemical behavior of this redox couple. As the applied potential is positively scanned during a CV experiment, \(Fe(CN)_{6}^{3-}\) undergoes oxidation on the surface of the electrode, resulting in a characteristic ipa on the voltammogram. In contrast, when the potential scan is reversed, \(Fe(CN)_{6}^{4-}\) reduction occurs at the electrode, leading to a cathodic peak current (ica). Although the CA provides complementary information. Applying a potential of \(-0.4\) V in a CA experiment favors the reduction of \(Fe(CN)_{6}^{3-}\) due to its more negative reduction potential compared to the oxidation potential of \(Fe(CN)_{6}^{4-}\). The concentration of the \(Fe(CN)_{6}^{3-}/Fe(CN)_{6}^{4-}\) couple significantly affects both CV and CA experiments. Increasing the concentration in CV experiments leads to higher peak currents (ipa and ica) due to the greater availability of  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Designed System**} & \multirow{2}{*}{**Measurements**} & \multicolumn{2}{c}{**Number of**} & \multirow{2}{*}{**Current Range**} & **Supported** & \multirow{2}{*}{**Software Interface**} & **Wireless** \\  & & & **Lights** & & **EIS** & & **Communication** \\ \hline P-EcStat (this work) & EC-PEC & 7 & 1 nA–18 mA &  
redox species for reactions in the WE. Similarly, in CA experiments, a higher concentration results in a higher initial current but a slower current decay due to the larger initial pool of \(Fe(CN)_{6}^{3-}\) available near the electrode surface, which takes longer to deplete. Consequently, the differential current density of the initial stage and the steady stage after 2 s increases according to the increase in \(Fe(CN)_{6}^{3-}/Fe(CN)_{6}^{4-}\). In this study, both commercial and developed devices exhibited a linear increase with increasing \(K_{3}Fe(CN)_{6}/K_{4}Fe(CN)_{6}\) concentration. However, the deviations in the results, as clearly shown in Figure 7b with the commercial device's slope value of 0.2498 (black line) and the slope value of the developed device of 0.2182 (red line), could potentially arise from slight variations in asynchronous experimental setups or electrode positioning.