Project Logs

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• Moving Forward

  Juan Albanell • 08/11/2014 at 09:19 • 0 comments

  The software and hardware are ready and working, but there are still improvements that need to be made before this product could be fully marketable. The first big focus would be to improve the target temperature algorithm to make it smarter over time and account for the climate outside the home and the season to have both cooling and heating. Another part of the improved algorithm would involve adding the option to schedule temperature settings, from daily patterns to monthly events. A more complex feature to add would be to change room priorities based on the users’ locations in the house. This could be done by adding a bluetooth chip to the shelºF Sense and make it perform the functions of an iBeacon or with a low power PIR motion sensor. With those improvements to the current project the shelºF system would be able to provide a superior offering at a better price than the current competition. The table below shows that at 1 unit pricing the cost is under $100, where the Nest is $250, and the costs can still be halved if the components are purchased in bulk. Most importantly it would move the industry in the right direction by making the Internet connected thermostat truly wireless.

  shelºF Act		shelºF Sense (TempBook)
  imp001	$25	imp002	$25
  April Board	$7	PCB	$2
  Relay Board	$3	Power Supply	$2
  Enclosure	$2	Temp Sensor	$2
  Wall USB Power	$5	BLE	$8
  Batteries	$1
  Total @ 1 unit	$42	Total @ 1 unit	$40

• Demo Video

  Juan Albanell • 08/10/2014 at 10:24 • 0 comments

  So everything is working properly and I made a demo video to show it. It's short and simple to show how easy it is to use shelºF. The lightbulb was the easiest way to simulate a heater and it did the job quite well. So what you see is the actual system with temperature changing! 
  I will probably make a longer video later showing all the app details and going over the TempBook board.
  Enjoy!

• The Build Process

  Juan Albanell • 08/09/2014 at 23:58 • 0 comments

  As can be seen in the build instructions, since everything I designed and coded is open source, it is easy to get shel°F setup and running in no time. But during the build process I experienced a few difficulties that I thought would be useful to share:

  
  

  • The Si7021 sensor comes in a tiny hard to solder package. A heat gun could be used to put it down and make things easier but it could tamper with the sensor according o the datasheet. My solution was to put a little bit of solder on the center pad and slide the sensor into position making sure it is connected to the center and not moving. Then, heating the sides of each pin on the chip and the pad, you add a little bit of solder to create the connection.
    
  • The Si7021 has a sticker on the top that needs to be keep on particles that could make the sensor malfunction. I accidentally removed the sticker on one of my sensors at the start and the readings were pretty much the same as a sensor with the sticker. That said in the long run things will probably become more inconsistent so since there is no harm, keep the sticker.
    
  • The book is pretty simple to hollow out if you follow the link to the instructions closely. One thing to note is that if you cut out the top of the book to make the sensor pop out it is best if that is not the only way the heat from the board can go. To prevent the creation of a chimney, you can either block the exit by not cutting out the edge and having the sensor slide out through a small opening or you can create another larger chimney on the side or bottom. I didn't do either and the results have been fine, but it doesn't hurt to make the design more robust.

• Origin of the Design

  Juan Albanell • 08/09/2014 at 00:26 • 0 comments

  The original idea, to replace the wall-mounted thermostat system, was born in a recent Electric Imp Hackathon. Later on this concept would develop into the shelºF three part solution consisting of an actuator, sensor and controller. But the design of the project was decided very early on, especially regarding the sensor and the controller.
  The sensor had to blend into the home, the issue with the wall-mounted unit is that no matter how pretty you make it, like Nest's product, it still can clash with the overall design of your home. The first solution, which eventually led to the TempBook board, was to put the sensor in a hollowed-out book. This is an item that is abundant in most homes and therefore goes by unnoticed, and it can be built very easily (tutorial I used). Future solutions would involve other hidden, easy to set up objects, such as a plant pot or a picture frame.
  The controller had to be very simple and intuitive, while breaking with the original thermostat controls. The resulting design was a comfort-based system, where the user choses if they feel cold, cool, ok, warm or hot. While this is not the conventional system it gets rid of the confusing numbers that no one needs to know, since all that matters is how you feel.

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