Device data
Manufacturing files https://www.thingiverse.com/thing:1183185 CERN-OHL-S Start OSHWA certification
Project data
Authors Peter Gorecki 2015 Yes No USD 19 Download Upload your project too!body.poncho-dark-mode .mw-parser-output .mw-ui-button{background:#303134;border-color:#3c4043;color:#bdc1c6}@media screen and (max-width:500px){.mw-parser-output .button .mw-ui-button{display:block;margin:.5em 0}}

This is a 3D printed Security Siren that could be used in low income areas where theft or other problems are an issue. The purpose of the siren is to get the attention of others nearby when a crime or other emergency is happening. Because crime rates are sometimes higher in lower income areas it would be beneficial to provide a low cost alternative to these areas.

This siren has a 5:6 frequency ratio, also known as a untempered minor third. Having two clashing tone simultaneously makes the siren more noticeable.

This has been improved from other designs, having fewer parts for ease of assembly, using an electric motor rather than a hand crank ed siren, and by having 2 tones instead of 1

## Bill of Materials

Non-Printed parts

1. 2 X 3mm dia X 10 mm length fine thread socket cap screws ~ $0.66 total 2. 2 X 3mm dia split lock washers ~$0.50 total
3. 13.6 V 6290 RPM Johnson electric motor part number: 9167AJ ~ $3.95 4. 12 V 4 amp AC-DC power supply ~$2.99
5. 2mm hex wrench ~ $0.30 Printed Parts 1. Stator ~$5
2. Rotor ~ $6 Total Cost ~$19

## Source and STL files

The STL files are available on thingaverse, here is the link:

## Tools needed

1. 3-D printer, I used the Athena: MOST Delta RepRap3-D printer
2. 2mm hex wrench
3. Wire stripper or something to strip wires safely

1. soldering

## Technical Specifications and Assembly Instructions

1. Stator print time estimate ~ 5 hours
2. Rotor print time estimate ~ 5 hours
3. Include assembly time estimate - 30 minutes

To assemble:

1. Print stator and rotor
2. Cut and solder power supply wires as show in picture
3. inset motor into hole in stator and secure with screws and lock washers using the 2mm hex wrench
4. Insert motor shaft into rotor. This is a pres fit onto a spline shaft, so it will require a bit of force, make sure to push the rotor on straight as shown in picture.

### Common Problems and Solutions

• Include common mistakes/problems to avoid in building your OSAT and how to overcome them
1. Make sure to tighten screw snugly onto lock washers so they don't come loose from vibration
2. Make sure to push the rotor straight onto the motor shaft, or the hole might get damaged and the rotor could be off center and unbalanced

## Cost savings

• If your solution is not a low cost one then it is not really appropriate.
1. Estimate your costs : Approximately 390 g pla ( ~ $11), cost of non-printed parts ( ~$8 ) = Total: $19 2. Similar sized air raid style sirens were anywhere from$35.15 to \$89.99
3. This means percent savings is somewhere between 46% and 79%
Page data
Type Device, Project 3d printing, alert, siren, security, safety, motor, plastic, power supply SDG09 Industry innovation and infrastructure Peter Gorecki, Kathy Nativi 2015 CC-BY-SA-3.0 MTU, Michigan_Tech's_Open_Sustainability_Technology_Lab, MY4777 English (en) 217 Peter Gorecki, Kathy Nativi (2015). "Dual Tone Air Raid/Security Siren". Appropedia. Retrieved August 18, 2022.
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