Team Members:
Thomas Driscoll (tfd2)
Kelvin Ma (kelvinm2)
Rishabh Anand (rishabh3)
Statement of Purpose
In the modern era, as products become slimmer and more technologically focused, we feel that it would be imperative to update the average bike lock with this system. We propose the development of a bike lock that will only open after the push of a remote controlled button, which will be small enough to fit on a key chain. This product will be easier to use, more secure against lockpicking thieves and an over-all better safety mechanism.
Background Research
Many mundane, everyday areas are utilizing remote-controlled locks. Many houses have been using security systems like this for years, with each generation becoming more and more sophisticated. However, mobile areas, notibly cars, have begun using these locks as well. Due to the abudnace of bikes used by college students in the United States, and bicycles being the most common form of mechanical transportation worldwide, we can see a huge market that would highly value a easy and secury bike lock, without the hassle and bulk of a key.
Design Details
System Overview
The device will have two pieces:
- A handheld remote control, goes with the user
- A physical lock, stays on the bike
The remote will be used to enter a binary sequence, which will be transmitted to the lock, which will verify the sequence internally and lock and unlock accordingly.
Remote
The remote will have three buttons, which will qualify as our sensors.
| Button 0 | Binary key 0 |
|---|---|
| Button 1 | Binary key 1 |
| Button 2 | Code reset |
The remote will use RF signals to communicate with the lock controller, transmitting the keypresses synchronously.
Lock device
The lock device will consist of the physical lock securing the bike, and the lock controller responsible for locking and unlocking it. Constructing a secure physical lock mechanism is beyond the scope of this project, which will focus on the lock controller much more than the lock mechanism itself.
The lock controller will have RF sensors which will pick up on the signals sent by the remote. As the controller receives each bit from the remote, it compares it with the corresponding bit in its internally stored keycode. For this project, the keycode will probably be 8 bits long, though this can be arbitrarily scaled. Once the controller has received 8 bits of valid input, it will open the lock mechanism. If it unlocks, or receives a Code reset signal, it will return to the beginning of the 8-bit sequence and continue listening. To re-lock the lock mechanism, the lock device will have a simple button on its surface.
A stretch goal of this project will be the inclusion of a fourth input which allows the code to be changed via remote (like a password), as opposed to it being hard-coded into the controller for the lifespan of the device (like a combination lock).
Parts
Ardunio Uno
complete with Arduino Boot loader
8 or 16MHz Crystal and 18pF capacitors
3.3V or 5V Voltage Regulator and 47 µF capacitor
PCB mount reset switch
10K pull-up resistor
0.1 µF capacitor for self-reset
LED and resistor
220 Ω resistor
Sender and receiver
Servo Motor
Power Supply
IR Receiver
Hall Effect Sensor
Possible Challenges
1) The most obvious challenge to us will be getting the electromagnetic pulse that locks and unlocks the bike working. We will do independent research to find out possible solutions to deal with this problem.
2) The next problem will be dealing with the communication between the remote control and the lock. As none of us have experience in remote controlled programming, we will be looking into online tutorials and solutions.
3) In terms of practicality, the lock could be shorted with a short burst of current to trick the lock into opening. How would we prevent thieves from stealing using this new method?
Weekly Updates
Week 1:
After having our project proposal reviewed by the TAs, we were given approval for our project, with the condition to add a block diagram. Now that our outline had been approved, we went to work on research. We looked into hall effect sensors to control the magnetic lock and the IR receiver to act as the wireless communication device. Due to a schedule mishap, we were in the Friday lab, so our next meeting will be Monday (in 3 days time) to get back on track. Due to the short turn around, our main goal will be continued research in possible components and design ideas.
Week 2:
After continuing to research and develop our project, we are have settled on using the IR receiver as our communication device. We decided we also need to use an IR LED to determine a variety of functions (mostly making sure the signal is being sent/received). Further, we will be using an Ardunio as to handle info input, simplifying the potential for building our own logic gate system. We will be using logic gates solely for the shift register. For the next meeting, we will each continue respectively researching possible ideas and solutions, with each group member requiring to bring two ideas and inputs to the next meeting. Kelvin will bring a proposal for how he would build the shift register, Thomas will work with the Arduino and develop a familiarity with IR communication and how to apply to get the signal to the hall effect sensor, and Rishabh will analyze the signal from the remote to determine if it is correct and research that.
Week 3:
The team spent most of the time developing our skill sets. Thomas has been dealing with the Arduino, working on the modules for the regular ECE 110 lab to better understand how to work with the computer, as well as doing independent projects. His goal for the next week will be to write a code for the Arduino that varies the voltage with the VIN pin and to build the working circuit with the Arduino and the IR receiver. Rishabh has been working on figuring out how to develop a threshold for the IR receiver so that it will recognize our input and generate a value to the logic gates. Kelvin has been working on the logic gates and how to get the emp to generate based on the input from the IR and the Arduino.
Week 4:
The team began real, concrete steps towards completing the project. Thomas developed a duty cycle with an analog voltage for the Arduino. All he needs is the period and voltage desired for the IR receiver. Rishabh took over building a working circuit with the Arduino and the IR receiver. Due to technical problems, Thomas and Rishabh will be working over the week to try and fix the code/circuit so it will generate true/false values (essentially turning the emf on or off in the magnetic lock).
Week 5:
Kelvin finished most, if not all, of the work on the digital logic gates, essentially leaving only the work on the IR receiver input/output. Thomas and Rishabh have been working on that and plan to meet on Saturday to finish all the bugs in the system. There was some debate on whether to continue using the Arduino (the current group consensus to do so). We are getting close to having a working prototype, with a generous timeline of completion in 2 weeks (however it could easily go longer).
Week 7:
After a debate the previous week, we have settled on using a SN74LS624 to make a clock that will respond to the duty cycle generated by the Arduino, based on the code Thomas previously did. Kelvin is building the IC clock, with research assistance on the how-to from Thomas. Rishabh is currently working to make the PWM match up with the clock. The main obstacle here is to get the PWM working. As the initial project presentation is next week, we have agreed to meet this weekend (Saturday, at 2 PM, in Nugent Hall) to go over eveything one last time.
Week 8:
We installed the final missing pieces of our bike lock circuit to produce a functional bike lock prototype with simulated input and output. While we were not able to get the clock IC or the infrared transmitter portions of the stack working, the high level circuit is functional, and thanks to simulated input from an Arduino, we are able to test and verify that our decoder circuit (the bulk of our project) is functioning as expected.
References
http://www.instructables.com/id/Remote-Controlled-Door-Lock/
http://www.safewise.com/home-security-faq/electric-door-locks
http://www.sdcsecurity.com/docs/eblasts/whitepapers_emlocks.pdf
Posted by pispati2 at Sep 26, 2016 15:50
