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Automated Security Gate


A childcare center needed to improve the security of their parking lot due to the unwelcomed trespassers and installed a gate. After they installed the gate they encountered a problem with the gate being too heavy and difficult to open. Whenever the children’s parents are coming to pick up their children the teacher has to open/close the gate manually which is a time-consuming process due to the weight and the structure of the gate. Therefore they have reached out to us to help improve the security system and ease the use of the gate.

Samuel Smith Razvan Marinescu Razvan Gavriliuc Hunter Ross Chance Bowman Acknowledge help of others: Jeff Randolph Justin

Problem Statement

The present gate is too heavy to be easily maneuvered. We need to redesign the hinge mechanism and automate the opening and closing of the gate by remote.

Design Specifications

1. The gate must be automatic

2. Children must be able to open/close the gate (remote control)

3. Must change the hinge system

4. Must be able to open/close the gate during winter (snowy and frosty days)

5. The gate must be lockable

6. Must be easily maneuvered

7. Must be long enough to cover the entire entrance (approx. 20 feet)

8. The gate has to be installed on uneven ground

9. Power must be pulled from the childcare building

10. The mechanism must be strong enough to open/close the heavy gate

Background Research

There are a few types of gates that we thought about. One of them would be a sliding gate. The advantage that a sliding gate has is the open/close motion. The drivers don’t have to be careful about being hit by the gate. This model wouldn’t work for our situation because the gate is placed on uneven ground.

Another type of gate would be a double swing gate. With most of the gates found online of this type we ran in the same issue, they are built for even ground.

The third type of gate that we were looking at was the barrier gate system. As for all other types presented here, the price of this gate is over $1500 without including the automation and anything else we need to finish the project. We also have to consider the length of the gate, which is longer than normally sized barrier gates.

Concept Design 1

  • Our first design idea was to take the whole gate, sleeve and all, off the post and mount it to hinges mounted on the original post. Then we would automate it by using a remote controlled motor that would have a gear on top to turn a chain that is wrapped around another gear attached to the gate, similar to a bike, causing the gate to rotate around the hinges. This would eliminate the need for new gates; however, this would also require double the work since there are two side of the gate.

Concept Design 2

  • Design 2 uses the same hinge system as design 1. In this scenario we use a hydraulic piston to open/close the gate. This allows for simpler set up, and less maintenance than a sprocket and chain. As with the previous design, we would need 2 hydraulics, one for each gate.

Concept Design 3

  • Design 3 is very different than the previous 2. In this design we decided to get rid of the very heave gate, and replace it with a single raising gate arm. The main advantage to this design is that only one side of the gate requires automation. The gate would only require 1 hydraulic for opening/closing. The disadvantage is that aluminum/fiberglass gate arms can be very expensive, especially when durability is a concern.

Selected Concept Design

After analyzing all the design concepts, we decided to go with concept 2 but modified to meet our given specifications.

Overview of Selected Design

Because of the high price of steel, we decided to use the old gates. The old gates had a sleeve attached to them which connected the gate to the fixed post. We decided to cut the sleeve off and replace it with a steel rectangle to which we will weld hinges and finally assemble it to the post. The gate next to the school will be automated while the opposite gate will not, as requested. An electric motor will be used to open/close the gate which will be powered by a 12V battery charged by an AC transformer.

Engineering Analysis 1

For analysis 1, we found the stress in each hinge and compared it to the maximum stress the hinges could withstand, to make sure our gate would operate without failure.

Engineering Analysis 2

For analysis 2, we decided to calculate the mobility to confirm our belief that our gate would be a one degree of freedom mechanism.

Engineering Analysis 3

Then we calculated the torque needed in order to make the gate move.

F = M*G, F = force, M = mass, G = gravity, M*G = W, W = weight.

T = F*r, r = radius.

W = 99 lb, r = 5.5 ft

F = 99 lb, T = F*r = (99)*(5.5) = 544.5 lb/ft.

After finding that calculate we looked for a motor that could supply that amount of torque, so it could move the gate.

We find the Mighty Mule gate opener that Generates 680 lb/ft of torque at 12 V.

CAD Drawings

Bill of Materials

Document Fabrication Process

Testing Results

After installing the gate, we programmed the remotes and instructed the teacher how to use it. We tested the gate and it was opening/closing as we expected.

Instructions for Safe Use

For safe use of this gate, please do not sit or climb onto the gate. Also when gate is opening stay clear of its swinging path. Do not try to open the gate while it is locked. To open the gate, point the remote at the antenna that is on the pole by the gate. Click it once to open it and do not attempt to close it till it has fully opened and come to a complete stop. Please make sure there are no cars or objects in the gates path, it could cause some small damage! Make sure to keep the gate lubricated with grease every 4- 8 months so it will open properly.

Project Summary/Reflection

This project was what we all wanted to experience while doing school, real-life experience. We learned how to work as a team, to finish work at a certain deadline and most important, how to apply engineering skills in the manufacturing process. We want to thank Dr. Canfield for this opportunity and also Jeff Randolph and Justin for their help with the project.


2018 Fall