When I applied for the Ultimate Raspberry Pi Bundle, I took a little time to peek at the products included in the package. I've seen Raspberry Pi's before, seen friends make them into cool projects, but have not actually used one myself. I have worked with a few different flavors of Arduino, a Parallax Propeller Board of Education and done a tiny bit with ATTiny micro controllers, but I am a software engineer at heart, so I'm still learning the hardware game. My first reaction to the bundle was one of intrigue, lots of gadgets to try, some I had not even read about. Next I noticed there appeared to be some overlap of function, for example an LCD display and another LCD display that needs to be soldered together ...that's ok, displays are good.
Anything appear to be left out of the "Ultimate Bundle"? Well, there's no case I guess, but that's a style thing and for my project I will probably need a custom case anyway. No cable or wall wart (er I mean power adapter) maybe, we'll see. A super minor thing would be the cobbler needs a breadboard to be useful, that's fine, I have those.
Those all seemed like pretty minor issues, the real challenge is to come up with a project that fits this eclectic package, here's what I proposed:
As I said in my first blog post, I wanted to design a temperature sensor for the local food-shelf. It seems the Ultimate Pi Bundle would allow me to pretty much implement this worthy project, provide reviews for element14 and probably add some creative bells and whistles...also know as feature creep...adding on requirements that the customer did not really ask for.
I understand the base requirement to be simply monitor temperature range in the refrig and freezer unit, then use either the available wifi connection and or a cellphone interface to notify the appropriate Channel One employees of issues. By using Pi, I'm sure I could allow easy configuration of settings and viewing history information from an on-board web-server...boom done!
But wait, there's more, now with the Ultimate Raspberry Pi Bundle...could I add more?, let's see
- WiPi - wifi is essential for my current base design
- Adafruit RGB Positive 16X2 LCD & Keypad Kit - a beautiful solution to add an onsite Temperature Status display
- PiFace Digital plugs could allow us to add sensors to the display case doors and signal an alarm if the door is open for too long of a time (something that has caused problems in the past)
- PiCamera could be useful to see who or what is blocking the door, or for security if someone opens the door during off-hours.
- ChipKit Pi could be used to provide custom configuration slides/buttons on site as opposed to, or in addition to the proposed web based configuration options
- Gertboard and Pi Cobbler would allow easier prototyping and debugging of our design.
So in order to not get carried away, I visited ChannelOne to check on their real requirements.
I met John on a Friday afternoon just as the Food-Shelf was closing, he was happy to talk to me especially since he likes the idea of a free temperature monitoring system and the only thing on his agenda for the day was cleaning :-)
We looked over the refrigerator system, looked for power sources, checked the wifi signal and inspected the larger cold storage warehouse to see what their monitoring system looked like.
There are two units like the above, one is a refrigerator unit and one is a freezer unit. I'll need to monitor the temperature range of each separately.
Here's what we decided:
- the base requirement is a bit more complicated, the valid temperature target (33F in the fridge unit, and -10F in the freezer unit) needs to vary depending on the time of day and probably the time of year. During business hours, and especially in the summer, since the doors are opened by customers and stocking personnel the fridge could possibly fluctuate all the way to 60F. So we agreed we need a Business Hours Range and an Off Hours Range, and a way to indicate what business hours are. (Another reason for these 2 ranges is reaction time to the problem. Becuase if 60F is occasionally allowed during the day, if the cooler hits 60F at night, this is not acceptable because it will likely soon hit 70F and it may take a while till someone can address the problem)
- the door ajar alarm - my parents used to have a car with a voice chip that literally said "The door is ajar" when the door was left open. While this may seem cute at first it can be kind of annoying. That's what we decided about the door ajar sensor I originally proposed...customers and stockers have a ligament reason to keep the door open. So instead we realized we need an audible temp range alarm. Originally we were just going to send an email or text message to someone when the range is out of hand, but we decided that during the day, an audible alarm when the temp is out of range is also obviously needed.
- Snooze Alarm - a good use of sensors on this project would be a snooze alarm. If the range is out of wack, it's probably going to take people a while to fix the problem...we'll need a way to silence the annoying alarm. A button on the unit would be preferred.
- Text don't just email - the original design was to send an email when the temp range is not correct. After talking to John and Mike in the warehouse they pointed out that most people don't read email at midnight (really?) and a text message would be much more effective. Of course this should go to more than one person due to vacations etc.
- Location of display - we carved out a good spot to mount the finished product, a power source is available, we'll be outside of the cold of the unit (figuring the Pi would probably not last as long in extreme temp conditions) and the LCD will be visible to staff.
- Power Outage Warning - the original brainstorming on this project thought assuming Channel One has a UPS on their computers and wifi, we might be able to have a battery backup Pi, detect a power outage and send a warning. However we decided Channel One has generators and a system set up for power outage notification.
- Security Camera Function - another bell and whistle that isn't needed. While we could take a picture and send an alert if someone opens the freezer unit after hours, this would require is to add door sensors or motion sensors and isn't really needed since the building is already under multi-camera surveillance
Ok, I think that is about it, KISS Keep It Simple Stupid...let's get working on these requirements before there is more wasted milk.
I'll figure out another way to review the entire kit of parts...I've wanted to buy a Pi for a while anyway :-)
Oh, I this week I also took some photos of the products I received: