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EInk display for power price and car status

Discussion in 'Model S: User Interface' started by Banahogg, Apr 7, 2013.

  1. Banahogg

    Banahogg Member

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    I saw a link to someone using a Kindle as a weather display (Kindle Weather Display | Matthew Petroff) a few months back and was intrigued, but not quite enough to actually start on the project.

    A week or so ago, I was trying to describe the E-9A TOU rates to my wife and her main comment was that it sounded complicated. I'm sure the fact that I kept confusing the E-9A times with the Schedule EV times was a significant contributor to her confusion (nothing causes more confusion than getting an explanation from someone who is already confused). Thus was born the Weather+EV display project:

    kindledisplay-mounted.jpg

    Technical details:

    It basically follows the flow from the original project, though with a few simplifications, especially on the Kindle side:

    - There is only one script on the Kindle which is called from cron. It checks for the power process and stops it if necessary, eliminating the init script
    - The server constructs the image on the fly rather than having dueling-banjos cron jobs. It takes a second or so to pull in all the information, but blocking one server process for 1 second seems like a small price to pay for the simplification
    - The car information comes from the last output from my logging program rather than hitting the Tesla REST server again.

    Unfortunately, because of the trickiness of jailbreaking the Kindle and the server config, it's not really something that's possible to package up for others to use, but hopefully can serve as inspiration for others of a technical bent.

    In the next phase of the project, I'm hoping to move it to a wood frame like Kindle Weather Recycling Station - Imgur with help from a friend of mine who is expert at woodworking, in exchange for making a METAR display version of the same.
     
  2. NigelM

    NigelM Recovering Member

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    I don't claim to understand most of what you wrote, but it looks cool!
     
  3. Ocelot

    Ocelot Member

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    agree, on all f(r)onts.
     
  4. dtich

    dtich #P708

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    fantastic. love this open source world. or 'hacksource' as the case may be, :)
     
  5. doug

    doug Administrator / Head Moderator

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    This is a great idea, particularly since the Kindle is relatively low cost and has low power consumption.
     
  6. EdA

    EdA Model S P-2540

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    This is sweet...

    You and I should talk about getting the Jetson's whirr to come out at speeds < 18MPH.....
     
  7. AustinPowers

    AustinPowers Total Smeghead

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    +1 It looks cool, I just don't understand the how or why one should need such a thing. Power price? Here that is constant all year round. Weather stations are hanging around almost everywhere anyway, and the car status I can see on the smartphone app, no?

    Not to say that it isn't a nice little gadget and a fun piece of hacking.
     
  8. Robert.Boston

    Robert.Boston Model S VIN P01536

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    It's too bad Germany hasn't adopted time-of-use or real-time pricing; it would help integrate all that solar and wind that are being added if customers could see when power is cheap (or dear). I think the motivator for the eInk solution was the complexity of the retail tariff structure in the San Francisco area.

    A long time ago, French households were given a little gadget that glowed red, yellow, or green to indicate peak load periods. Simple, effective, and informative. Apparently is really did help moderate peak-period demand even though there was no associated price signal.
     
  9. Banahogg

    Banahogg Member

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    Yup. The PG&E E9-A rate structure has 3 different rates whose times vary depending on weekend vs weekday and winter vs summer, but being on that rate saved us about $50 the first month we had it (we'll see about this month after this heat wave). I'm not sure how much having that information helps us save power though - I think my wife mostly ignores it...

    I've found having the range and charge status to be mildly useful, but as you say, a lot of that was just for fun. My server already polls the car every 10 minutes, so I just had the display rendering script grab the data from the last log entry.
     
  10. AustinPowers

    AustinPowers Total Smeghead

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    Wow, interesting system. Way different here. You chose your electricity company (out of the literally hundreds available) then as long as you stay with them your price stays the same (unless they decide to raise prices, which they usually do once a year - upon which time you search for a cheaper supplier and change to them).
    The incentive for not wasting electricity is the high prices in general here. You can only choose between bad (high) or worse (higher).
     

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