## 3 Results  
### Manufacturing Cost Analysis  
The total cost described in Equation (1) as \(T_{c}\) is defined as the relationship between the following: (1) the material part cost is considered as the material cost \(m_{c}\) and part weight \(p_{w}\); (2) \(p_{t}\) is the printing time; (3) the usage cost is determined by the cost of the printer \(c_{p}\), upgrades cost \(u\), maintenance costs \(m\), average lifetime \(a_{l}\), rated power \(r_{p}\), and energy price \(e_{p}\); and finally, (4) the part design cost is defined by the design time \(d_{t}\) and design hourly rate \(d_{c}\). \[T_{c}=m_{c}\bullet p_{w}+p_{t}\bullet\left(\frac{c_{p}+u+m}{a_{l}}+r_{p} \bullet e_{p}\right)+d_{t}\bullet d_{c} \tag{1}\]  
The full list of electronic parts used, and a subtotal cost can be found in Table 2. Alongside the motors, the drivers and batteries were considered. Also, the soldering supplies were considered for a comprehensive price capture. Some mechanical components from Table 3 were considered. In the subtotal, everything was considered, from the ball bearings used to the different types of fasteners required for the assembly of the parts. In Table 4, a list is presented of the different parts that were 3D-printed and their associated cost based on Equation (1). The cost of a single unit and the cost of the required number of parts are provided. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**No** & **Part** & **Number of Items** & **Price/Part** & **Total Price** \\  & & & **[RON]** & **[RON]** \\ \hline
1 & Pololu 1000:1 Micro Metal Geamororor LP 6 V (Pololu Corporation, & & \\ Las Vegas, NV, USA) & 3 & 145 & 435 \\
2 & Pololu DRV883 Single Brushed DC Motor Driver Carrier (Pololu Corporation, Las Vegas, NV, USA) & 3 & 17 & 51 \\
3 & Arduino Nano Every (Arduino, Somerville, Somerville, MA, USA) & 1 & 90 & 90 \\
4 & Duracell J 7k67 LR61 (Duracell, Chicago, Illinois, USA) & 2 & 28 & 56 \\
5 & Wendeekun Kit muscle sensor (Ardushop, Bucharest, Romania, EU) & 1 & 144 & 144 \\
6 & Soldering lead 0.8 mm 100 g (Ardushop, Bucharest, Romania, EU) & 1 & 19 & 19 \\
7 & Flux (Ardushop, Bucharest, Romania, EU) & 1 & 15 & 15 \\  & Electronical components subtotal & & & 810 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Electronic components costs. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**No** & **Part** & **Number of Items** & **Price/Part** & **Total Price** \\  & & & **[RON]** & **[RON]** \\ \hline
1 & Miniature single row deep groove sealed ball bearings MR72 ZZ & 14 & 3.4 & 47.6 \\  & (Ardushop, Bucharest, Romania, EU) & 25 & 0.45 & 11.25 \\
2 & M2 \(\times\) 12 mm screw (Ardushop, Bucharest, Romania, EU) & 14 & 0.9 & 12.6 \\
3 & M3 \(\times\) 12 mm screw (Ardushop, Bucharest, Romania, EU) & 14 & 2 & 28 \\
4 & Stainless steel torsion springs (Ardushop, Bucharest, Romania, EU) & 14 & 11 & 11 \\
5 & Textile cable Konger X8 Braider, 0.06 mm 10 m spool (Ardushop, & & & \\ Bucharest, Romania, EU) & 30 & 1 & 30 \\
6 & Brass threaded inserts (Ardushop, Bucharest, Romania, EU) & & & 140.45 \\  & Mechanical components Subtotal & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Mechanical components costs. In the process of assembly other miscellaneous parts were procured. The number of parts as well as the price and total cost can be seen in Table 5.  
In Table 6, the sum of all the subtotals gives the total cost of the prototype. The cost can be rounded to 1300 RON, which is the equivalent to 260 euros, making it suitable to be called a low-cost device. \begin{table}
\begin{tabular}{c c c} \hline \hline
**No** & **Component Type** & **Value** \\  & **[RON]** \\ \hline
1 & Electronical components subtotal & 810 \\
2 & Mechanical components subtotal & 140.45 \\
3 & 3D printed components subtotal & 311.82 \\
4 & Other components subtotal & 18.8 \\  & TOTAL & 1281.07 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Total component costs.