\subsection{Lifecycle Cost Planning and Time Value Money (TVM) Analysis}

\begin{center}
\textbf{Updated Cash Flow Diagram for Control-Based Station (5-Year Lifecycle)}
\end{center}

\begin{tikzpicture}[>=Stealth, scale=1, every node/.style={scale=1}]
  % Draw timeline
  \draw[->] (0,0) -- (6.5,0) node[right] {Time (Years)};
  \foreach \x in {0,1,2,3,4,5} {
    \draw (\x,0.1) -- (\x,-0.1) node[below] {\x};
  }

  % Year 0 - Initial Investment
  \draw[->, thick] (0,0) -- (0,-2.65) node[below] {- \$530};

  % Years 1–4 - Annual Operating Cost
  \foreach \x in {1,2,3,4} {
    \draw[->, thick] (\x,0) -- (\x,-1.2) node[below] at (\x,-1.4) {- \$120};
  }

  % Year 5 - Annual Cost + Salvage
  \draw[->, thick] (5,0) -- (5,-1.2) node[below left] {- \$120};
  \draw[->, thick, green!60!black] (5,0) -- (5,2) node[above] {+ \$200};

  % Labels
  \node at (3,-4.2) {Cash Outflows = CAPEX \& OPEX};
  \node at (5.8,2.4) {Salvage Value};
\end{tikzpicture}

\par \textbf{Cost Constrain:} The system is designed with strict cost constraints to ensure affordability for small-scale farmers and homesteaders. The goal is to maintain an annual operating cost below \$200 and a one-time hardware cost under \$1000, as specified in REQ-20 and REQ-26. The cost model incorporates hardware components, connectivity fees, and maintenance buffers.

\begin{table}[H]
\centering
\caption{Estimated First-Year and Annual Operating Costs for Current System}
\begin{tabular}{|l|l|l|}
\hline
\textbf{Category} & \textbf{One-Time Cost (USD)} & \textbf{Annual Cost (USD)} \\
\hline
Edge Device (Raspberry Pi 4 + Peripherals) & \$100 & -- \\
Sensors (Weather Station + Soil Moisture Sensor)    & \$200 & -- \\
4G Modem + SIM Hardware                    & \$50  & -- \\
Solar Power Kit + Battery Storage          & \$150 & -- \\
Weatherproof Enclosure                     & \$30  & -- \\
Data Connectivity (4G SIM, low-data)       & --    & \$6--\$12 \\
Preventive Maintenance Buffer              & --    & \$50 \\
Cloud/Remote Logging (Optional)            & --    & \$60 \\
\hline
\textbf{Total Estimate}                    & \textbf{\$530} & \textbf{\$116--\$122} \\
\hline
\end{tabular}
\end{table}

\noindent
The model assumes one centralized edge device performing both hub and compute functions. This reduces recurring data costs by minimizing transmission frequency and eliminates the need for cloud-hosted control services. The architecture supports expansion through additional sensors without significantly increasing operating costs.

Performing Trade-off study for not using alternatives as mentioned in House of Quality (figure \ref{fig:hoq})
\begin{table}[H]
\centering
\caption{10-Year Cost Comparison: Control-Based vs. Azure IoT System}
\begin{tabular}{|p{0.3\textwidth}|l|l|}
\hline
\textbf{Item} & \textbf{Control-Based System (USD)} & \textbf{Azure IoT System (USD)} \\
\hline
Initial Hardware Cost & \$530 & \$300 \\
10-Year Subscription Cost & \$0 & \$1,800 \\
10-Year Operating Cost & \$1,200 & \$1,200 \\
Salvage Value (End of Year 10) & -\$200 & \$0 \\
\hline
\textbf{Total Lifecycle Cost} & \textbf{\$1,530} & \textbf{\$3,300} \\
\hline
\end{tabular}
\label{tab:10year-cost-comparison}
\end{table}

\begin{table}[H]
\centering
\caption{Detailed Annual Operating Cost Estimate}
\renewcommand{\arraystretch}{1.2}
\begin{tabular}{lll}
\hline
Cost Item                          & Annual Estimate   & Notes \\
\hline
Replacement batteries \& parts      & \$40               & Rechargeables for sensors, valve batteries \\
Occasional sensor replacement      & \$50               & 1–2 sensors/year \\
Manual maintenance time (labor)    & \$50–\$70           & Self-service \\
Data storage backup (USB rotation) & \$20               & Flash drives \\
Cloud Services (avoided)           & \$0                & Azure IoT Central typically charges \$5–10 per device/month ⇒ saved \$60–\$120/year \\
Total Annual Cost                  & \textasciitilde{}\$160             & Under target \$ 200\\
\hline
\end{tabular}
\end{table}

\begin{table}[H]
\centering
\caption{Financial Model Input Parameters}
\renewcommand{\arraystretch}{1.2}
\begin{tabular}{lr}
\hline
Category                &     Value \\
\hline
Initial Cost (B)        &    625    \\
Annual Income (Benefit) & 180000    \\
Annual Operating Cost   &    160    \\
Net Annual Cash Flow    & 179840    \\
Discount Rate (MARR)    &      0.12 \\
\hline
\end{tabular}
\end{table}

\newpage
\begin{landscape}
\begin{table}[H]
\centering
\caption{6-Year Financial Model with MACRS 5-Year Depreciation (Landscape)}
\resizebox{\linewidth}{!}{%
\begin{tabular}{rrrrrrrr}
\hline
Year & BTCF & MACRS Dep Rate & MACRS Dep Deduction & Book Value & Taxable Income & Income Taxes & ATCF \\
\hline
0 & -625   & 0       & 0    & 625  & -125  & 0 & -625   \\
1 & 179840 & 0.20    & 125  & 500  & -200  & 0 & 179840 \\
2 & 179840 & 0.32    & 200  & 300  & -120  & 0 & 179840 \\
3 & 179840 & 0.192   & 120  & 180  & -72   & 0 & 179840 \\
4 & 179840 & 0.1152  & 72   & 108  & -72   & 0 & 179840 \\
5 & 179840 & 0.1152  & 72   & 36   & -36   & 0 & 179840 \\
6 & 179840 & 0.0576  & 36   & 0    & 0     & 0 & 179840 \\
\hline
\end{tabular}%
}
\end{table}

\begin{table}[H]
\centering
\caption{NPV and IRR Computation for 6-Year Financial Model}
\renewcommand{\arraystretch}{1.2}
\begin{tabular}{ll}
\hline
Metric & Value \\
\hline
Initial Investment (Year 0) & \(-\$625\) \\
Net Annual Cash Flow (Years 1–6) & \$179,840 \\
Discount Rate (MARR) & 12\% \\
Net Present Value (NPV) & \$851,222.79 \\
Internal Rate of Return (IRR) & 2882.7\% \\
\hline
\end{tabular}
\end{table}

\end{landscape}