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 =**Sustainability Analysis**=

**The Amazing People Detector **
Access article online
 * Louis E Garner Jr. **
 * Popular Electronics, June 1968 **

The people detector is a device that passively detects the movement of people and animals in the direct vicinity of the device. Its circuitry consists of a step down transformer to supply power, 8 diodes used in rectifier circuits, a MOSFET transistor for an input stage, two BJT transistors, a relay for switching, an amplifier IC for signal amplification, and many resistors and capacitors for loading and filtering purposes.

**4E Sustainability **
**Ecology ** The people detector can be used in nature to detect wildlife and is intended to be a passive, non-disruptive device. It does not give of any harmful radiation or chemicals. The antenna on the device is detachable and reusable for other applications. The other components used to create the device are not easily reused and recycled unless you built it on a proto-board. **Energy ** The main power consuming components in the circuit are the amplifier and the relay. The amplifier IC typically outputs 550mW of power with 45% efficiency. This is probably the source of the most power loss due to the fact that you cosume 670mW, over half the input power of the device, during signal amplification. The relay is usually dissipating power during its normal operation because it is in the on state when there is no movement detected. The relay operated at 12V and 40mA, therefore it has a typical power consumption of 480W. he total device power consumption should be on the order of a few watts. The power will typically be provided from a wall socket unless modifications are made to the device. **Economy ** The people detector is typically used as a hobby project. There is no profit to be made from the device. It can, however, ensure the security of the owner’s property if used to detect thieves. The most expensive part of the project would be the cost of printing the PCB and creating the housing, as most of the electronic components are inexpensive and easy to acquire. **Equity ** The intended use for the device is security. The application of the device benefits the owner alone and causes no harm or disturbance to others.

**Green Engineering principles **
**The green engineering principles are: ** 1. Engineer processes and products holistically, use systems analysis, and integrate environmental impact assessment tools. 2. Conserve and improve natural ecosystems while protecting human health and well-being. 3. <span style="color: black; font-family: 'Times New Roman',serif; font-size: 10pt;">Use life-cycle thinking in all engineering activities. <span style="color: black; font-family: 'Times New Roman',serif; font-size: 13.5pt;">4. <span style="color: black; font-family: 'Times New Roman',serif; font-size: 10pt;">Ensure that all material and energy inputs and outputs are as inherently safe and benign as possible. <span style="color: black; font-family: 'Times New Roman',serif; font-size: 13.5pt;">5. <span style="color: black; font-family: 'Times New Roman',serif; font-size: 10pt;">Minimize depletion of natural resources. <span style="color: black; font-family: 'Times New Roman',serif; font-size: 13.5pt;">6. <span style="color: black; font-family: 'Times New Roman',serif; font-size: 10pt;">Strive to prevent waste. <span style="color: black; font-family: 'Times New Roman',serif; font-size: 13.5pt;">7. <span style="color: black; font-family: 'Times New Roman',serif; font-size: 10pt;">Develop and apply engineering solutions, while being cognizant of local geography, aspirations, and cultures. <span style="color: black; font-family: 'Times New Roman',serif; font-size: 13.5pt;">8. <span style="color: black; font-family: 'Times New Roman',serif; font-size: 10pt;">Create engineering solutions beyond current or dominant technologies; improve, innovate, and invent (technologies) to achieve sustainability. <span style="color: black; font-family: 'Times New Roman',serif; font-size: 13.5pt;">9. <span style="color: black; font-family: 'Times New Roman',serif; font-size: 10pt;">Actively engage communities and stakeholders in development of engineering solutions. The people detector is not made up of any harmful chemicals or materials. It is long lasting and can be used for a number of applications. One can repurpose the device without creating waste. The device is created for benevolent purposes, and does not harm people in the community.

References:

Braun, David. "EE413 Sustainability Analysis." // Electrical Engineering Department - Cal Poly //. Web. 30 Apr. 2011. <[]>

Braun, David. " 4E Sustainability Analysis " // Electrical Engineering Department - Cal Poly //. Web. 30 Apr. 2011.

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<span style="font-family: Arial,Helvetica,sans-serif; font-size: small; line-height: normal;">Louis E. Garner Jr. " Popular Electronics June 1968 " // Southwest Technical Products Corporation //. Web. 30 Apr. 2011. < [] >