I have always wanted an inexpensive way to take unobserved pictures of wildlife in my neighborhood. This instructable takes parts of two existing instructables and brings them together with added features to create a cheap motion detection wildlife camera.
This project uses a re-purposed PIR sensor module from an air freshener to provide motion detection, an inexpensive key chain camera to capture images, and a TI msp430 microprocessor to provide the necessary brains. The microprocessor comes with TI's $4.30 Launchpad experimenter kit.
Step 2: Preparing the PIR Module
If you have followed the instructable https://www.instructables.com/id/Re-purposing-an-Air-Wick-Freshmatic-Compact-i-Moti/
your PIR module should look like the picture below.
We need to do a few things to make the module easier to fit into the project box.
1. Remove the two connectors.
2. Move the two large capacitors to the back of the board. Make sure that you put the
leads in the same holes that you removed them from. These capacitors are polarized.
3. Attach wires to Vcc, Gnd, and PIR sensor output. The second picture shows where
to connect the wires.
Step 3: Preparing the Camera - part 1
Many thanks to smb and his instructable https://www.instructables.com/id/Hacking-A-Keychain-Digital-Camera-for-Arduino-Cont/ on his discovery of the hidden screw that you need to remove to open up the case of the keychain camera that we are using.
Since we know where the screw is, you can use a Dremel tool or a sharp knife to remove the material just above the screw. Once it is exposed, you can remove it and the case easily.
After the case has been removed, unsolder the piezoelectric buzzer from the back. This buzzer is pictured in the second photo below.
The third photo shows the location of the two switches that we will later remove and the location of the voltage regulator that will be used to power the PIR module and microcontroller.
Step 4: Preparing the Camera - part 2
This step is the hardest of the project. You will remove the switches from the camera and replace them with transistors. You will also solder a wire to one of the camera's voltage regulators to source power tor the rest of the modules, and finally attach wires to the battery connections.
If you are a visual learner, you might find the diagram on step 7 helpful in understanding where the wires go. Also, the information in smb's instructible can help guide you.
When desoldering parts from a board with surface mounted devices, using solder wick is very helpful. It is a copper braid that "wicks up" the solder so the part can be removed easily.
1. Remove the shutter switch located near the top of the camera's PCB. This
switch has two leads and two supports. You have to unsolder all 4 points.
2. Remove the mode switch located near the bottom of the camera's PCB. This
switch has only the 2 leads holding it. There are no additional support points.
3. Solder a wire to the base of each of your two transistors. Note that
you must know the pinout of your specific transistors, do not blindly fellow the
pinouts I used. My transistors may have a different pinout than yours.
4. Solder a wire to the left most lead of the surface mount voltage regulator located
just above the mode switch's location.
5. Directly solder the collector pin of one of your transistors to what was the left most
lead of the mode switch.
6. Directly solder the emitter pin of the same transistor to what was the right most
lead of the mode switch.
7. Directly solder the collector pin of your other transistor to what was the left lead of
the shutter switch. Do not attach to the support point that is near the edge of
the board. See the diagram on step 7, if you are unsure.
8. Directly solder the emitter pin of the same transistor to what was the right lead of
the shutter switch. Again, do not attach to the support point.
9. Finally, solder wires to both the the positive and negative battery points on the
camera's printed circuit board.
Step 5: Preparing the Camera - part 3
To retain the use of the LCD screen you have to retain its support. I achieved this by using a jig saw to cut out the black plastic portion of the front of the camera case. This is shown in the photo below.
note: See FAQ on step 11 for alternate method.
The second photo shows the two screw posts that you want to retain to support the LCD.
The third photo shows the plastic piece mounted on the camera. You want to do this after you have completed the wiring to the camera PCB board.
You attach the screws from the back of the camera's PCB board into the plastic. I found I also had to create a third support using hot glue to get the LCD to work consistently.
Step 6: Wiring the Bread Board
The picture below shows how to layout the microprocessor bread board. The red traces are the runs made on the copper side of the board. A fourteen pin dip IC socket is represented as a black rectangle with the IC pins displayed in small blue squares. The socket is placed on the non-copper side of the board, and the numbering reflects this perspective.
All components are placed on the non-copper side of the bread board.
The two yellow traces shown in the picture are jumpers that are placed on the non-copper side of the bread board. The black circles represent connection points.
The second photo shows the schematic.
Step 7: The Circuit
The picture below shows how the modules of the Motion Detection Wildlife Camera are connected together.
note: Use the pinouts for your transistors. Do not assume they are the same as mine.
The diagram below does not show the plastic piece that you cut out to hold the LCD to the camera PCB board.
Step 8: The Code
The c code for the MSP430 microprocessor is attached below. The picture shows a simplified flow diagram of the program.
If you are new to microprocessors, particularly the MSP430, I suggest that you look over the instructions in the instructible https://www.instructables.com/id/MSP430-Based-Chronulator-using-Launchpad-chip/
. It gives a step-by-step on how to use the Launchpad and the IAR Kickstart compiler. For this project you only have to place the chip in the Launchpad and transfer the program, then put the chip in your bread board.
Step 9: Drilling the Project Box
I always find getting the holes in the project box correct a little daunting. I have tried to make it easier for you by providing the measurements in the three photos attached to this step.
Only the holes for the camera are critical, the holes for the PIR module and switch can be moved about slightly without any major concern.
Step 10: Assembling the Project
The picture below shows how the modules fit in the project box. I placed them in to the box in the following order.
2. PIR module
4. Microprocessor bread board
I wired each module's connections before I put it into the box. This made the soldering easier.
Each module is held in place by two small spots of hot glue. Consideration of how you would unglue if you had to should be made when tacking the modules into place.
I found that I had to add a drop of hot glue between the camera PCB board and the plastic holding the LCD in place to make sure of consistent LCD readings. The two screws were not enough.
Step 11: Using the Camera and FAQ
To transfer pictures from the camera you must install the driver and MyPicture application that came with it on to your computer. You do not need to install the bundled photo editing program. The camera has SRAM memory. This means that if the camera loses power the pictures are lost. We use this feature to re-initialize the camera.
To use, start with the switch in the off position, wait 10 seconds, then turn the switch to on. You will see the LCD switching through several modes. You have about 30 seconds after you turn the camera on to position it and walk away before it will start to take pictures.
When you retrieve the camera to see what you got, do not turn it off . Go to your computer and plug in the USB cable, start the MyCamera application, and download the pictures. After you have saved the pictures to your computer, you can turn the camera off.
Q: What is the resolution of the camera and how many pictures does it hold?
A: In high resolution mode the camera's resolution is 352 x 288 pixels. It can hold 20
non-compressed pictures or 60 compressed pictures. The program places the
camera in high resolution and compressed, so 60 images can be stored at a time.
If 60 pictures are taken the program puts the camera to sleep.
Q: What is the best distance between target and camera?
A: Because of the low resolution you want to be close, but not too close. I have found 3
to 6 feet from the target is best.
Q: What is the range of the sensor?
A: The sensor can pickup large movements at up to 15-20 feet. An example would be
a deer or human moving into the line of sight of sensor. At short range, less than 5
feet it can pickup a leaf blowing across the sensor. A very small movement, for
example a squirrel moving a hand from a pile of seeds to his mouth without
a stance change, might not trip the sensor. In this case, it helps to spread the
seeds from a large single pile to a small area so the squirrel has to move a bit.
Q: How do I change the PIR's sensitivity?
A: We can't change the sensor's sensitivity directly, however we can change the system's
sensitivity to a PIR trip. If you look in the code at the TA interupt service routine you will
find the following lines:
// set band time
cntr_val = 15000; // 15000 ~= 0.125 sec <----------- line of interest
cntr_val = 120000; // 120000 ~= 1 sec
By changing the cntr_val number in the line
cntr_val = 15000; // 15000 ~= 0.125 sec
we change how long a PIR imbalance must exist before taking a picture. I would not
change it to a number less than 4000 (~1/32 sec) or more than 30000 (~1/4 sec) .
Q: Why didn't you write the code to take multiple photos when triggered?
A: I originally had the camera take pairs of pictures spaced by 5 seconds, but I
decided that I preferred to have more "events" than sets of photos. It is just a matter of
preference. The code change is easy. It depends on how long you plan
to leave the camera unintended, the target that you are trying to capture, and the
purpose of your shots. For example if you want to know if there are deer going to your
location you would be interested in events and you might want to increase the
minimum time between shots. If you are looking for cute pictures (what I'm doing)
you might want to do sets of photos.
Q: How much did the project cost?
A: I was lucky and was able to buy both the air freshener and the camera from
Walgreen's on sale. Together they cost me ~$10. Normally they would be double that.
The microcontroller was part of the TI Launchpad kit which sells for $4.30 plus
shipping. The project box cost $4 from Radio Shack. The other parts were in my
junk box. So total cost between $20 and $30 dollars.
Q: Why didn't you just use the Launchpad instead of making a bread board?
A: I re-use my Launchpad for multiple projects, so I can't have it tied up in a project that
I plan to keep for awhile.
Q: Why did you put the transistors directly on the Camera's PCB board instead of just
attaching wires and mounting the transistors onto the microcontroller board, like
smb did in his instructible?
A: My first thought was to eliminate two wires and make the microcontroller board
simpler. In hindsight the collectors of both transistors could be tied to Vcc on
the microcontroller board, so no wires are actually saved. You could put the
transistors on the microcontroller board and just bring over a wire where the
emitter of each transistor are currently connected. If I had to do it again, this
is how I would do it.
Q: Could you not cut the front of the camera case, and attach it to the camera PCB
A: This is another hindsight moment, the way I did it worked out easy enough, but I had
a simple way to cut out the plastic. Others might not have this luxury, and retaining the
whole camera case front should work. I believe there is enough room in the project
box. You would want to remove the side with the USB plug so it would fit into the
hole in the project box side.
Q: Did you originally plan to use this particular camera?
A: No, I originally planned to use a type 808 keychain spy camera from eBay.
They are higher resolution, smaller, and have video capability. I actually bought one,
but the project kept being delayed because I was having too much fun with the 808
camera. When I had an opportunity to buy the Vivitar mini keychain camrea for $5, I
jumped at it, and the project moved forward. If I had used the spy keychain camera
the project would have cost about $20 dollars more due to camera price difference
and need to purchase a mini-SD card.