Matt Michels

2:26 A.M.

1/13/11

 

First Post/Starting Information

 

What has been done so far:  Aryeh, Andrew, and myself went to RadioShack/staples to buy some components for our project.  Current purchases include: (1) pen/laser pointer, (1) variety pack of photoresistors, (1) pack of 9V battery connectors, (1) 9V batteries, (1) 1.5-3.0 volt DC Motor (8300 RPM w/ load).  Along with this, each of us has individually installed the software components for the eZ430-Chronos Watch.  The demo program which comes with the microcontroller is quite intuitive.  It features an accelerometer graph (x,y,z cords), along with a heart rate monitor, pc mouse control, and a timer.  Attached to this page is a zipped folder with code examples for the microcontroller. [Examples include ADC conversions, Flash-writing, timers, and more...]  <--Link to the zipped folder.

 

Current thoughts - I need to figure out how to work with the watches pressure sensor, I suppose after this I'll upload some of the microcontrollers PDF documents.  Another thing - the laser pointer looks far too large. After disassembling it and realizing that a) there is a pen inside, and b) its just not what we were looking for, I think I'll search on-line for one of the 2-3 inch lasers.  I have my breadboard, I'll bring it to today's lecture and we can play with the photoresistors/laser.

 

USEFUL LINKS:

• eZ430 Wiki
• [MSP430 overview - videos, code examples, and documentation]

 

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Aryeh Kuller

3:50 P.M.

1/13/11

 

 

 

Today we tested our photoresistor to see how it work with our laser.  We set up a bread board with the largest photo resistor and tested the resistance when there was only ambient room light we found the resistance to be around 3-4 k ohms and with the laser we found with the resistance to be 180  ohms .   We then added a voltage source and a resistor to the circuit and test the the voltage across the photoresistor.  We set a dc voltage source of 5 volts across our circuit and added a resistor of 330 ohms  in series and measured what our voltage was across the photoresistor.  We tested various resistor to see how the worked together and found that a resistor of 1.6 k ohms to be most effective.  We then tested our various photo resistors and found that the smallest photo resistor was more effective because it gave greater variance between with and without the laser.

 

          without laser (4.074 volts)                 with laser(.501 volts)

  

 

Rough copy of our block diagram:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Andrew Mercante

10:20 A.M.

1/17/11

 

I found this website yesterday http://www.kpsec.freeuk.com/trancirc.htm and made the switch for an led using an ldr  just now.  We definitely need to play with some of the resistor values but the switch seems to work quite well.  

When the laser is focused on the ldr there is no voltage across the led.

When the laser is interrupted a voltage of 4.5V is read across the led's leads.

 

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Andrew Mercante

1:35 P.M.

1/29/11

 

Using the source code for serial communication and the circuit for the trip wire above, the msp430 will enter an interrupt and send the character 'y' every time the laser is tripped.

 

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Aryeh Kuller

 

1/31/11

1:40 P.M.

 

 

I have some websites and picture to show the progress that we have made withe project as well as some updates as to where the project has moved.  first the project has changed how we plan to link all of the hardware.  We were initally trying to link all the hardware throught the msp430 but due to its lack op ports and issues withe the watch hardware we have decide to use a computer to serially connect to the mp430 and the watch and use a script to link them to web cam that will take the picture and send an email.  some sites that we have looke at to help us with this are http://hackaday.com/2010/08/11/how-to-launchpad-programming-with-linux/, http://www.cyberciti.biz/tips/sending-mail-with-attachment.html, http://www.shelldorado.com/articles/mailattachments.html.  lastly here are some pictures to show the progress of the laser and photo resistors development for the project.

 

      

As seen above, we removed the actual laser from the laser pointer and wired it up to a bread board.  We then programed the msp430 so that when the laser is tripped an led turns on or off as can be seen in the second two pictures.

 

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Matt Michels

1:58 A.M.

2/2/11

 

A quick little update:  I've written a python script which as of now will read in accelerometer data from the eZ430-Chronos and detect large enough changes in the Z axis to be considered a "tap".  This portion of the project is required for enabling and disabling the security system via a 'tap sequence'.  The code isn't complete, but here is a snippit:

 

 

 

 

And here is an example of the output from that code:

 

I will be finishing the tap sequence tomorrow, and upon completion will update this blog post with final source code.

 

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Andrew Mercante

3:30 P.M.

2/2/11

 

Below is the circuit with the photo resistor wired to the launchPad.  This is the final circuit that will trigger an interrupt on the msp430.  It consists of 7805 voltage regulator, a power mosfet, and various resistors to achieve a certain voltage change when the laser's path to the photo resistor is interrupted. 

 

These photos show the both boards seated inside of a RadioShack project enclosure.

 

Below is a status LED, when the interrupt for the laser is enabled the LED is on,  and when the interrupt is desabled the LED is off.

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Andrew Mercante

1:00 P.M.

2/3/11

Using the accelerometer in the watch and some Python script, our computer is able to take in a tapping sequence as a code and either arm or disarm the trip wire.