• If I wanted to make a puck into an outside temperature sensor that I could read from my Bangle - how long would the battery last in the puck before it had to be changed if all it was doing was measuring outside temperature and supporting a bluetooth connection to the bangle watch when in range ?

  • If you just advertise (temp in the manufacturing data) with low frequency, your battery lasts a very long time. Getting into a connection will eat your battery much much faster.

  • Sun 2021.05.23

    'how long would the battery last'

    I found the specific answer for Bangle by taking a peek at the Bangle presentation page:

    http://www.espruino.com/Bangle.js

    Below the Power Consumption heading are the measured current draw values.

    See the following section on how to calculate an estimated duration with a brand new battery.

    post #2   Battery life of Bangle J.s - in real world situations

    Also understand that advertising interval, transmit power output and sleep durations need to be taken into account, along with number of times polling the temperature sensor is performed.

    See: Puck tips - increasing battery life

  • IMO outside temperature sensor is a waste of a Puck, you can get very cheap LYWSD03MMC thermometers (example https://www.aliexpress.com/item/40010957­35569.html )

    They are hackable with custom firmware available. Got one outside since autumn last year and it still works with first battery. It also survived winter without issue (someone also tested it in the freezer -20C).

    There is a thread about them here, you can certainly read them from bangle.

  • @HughB as @allObjects says you can set the Puck to advertise. If it's set as nonconnectable, advertising at 375ms (the default) and only updating temperature once a minute or so I believe you should be able to get almost a year out of it.

    If you reduce the advertising interval you could comfortably get a year. I'd be happy to post up some code for you if you want.

  • @fanoush, sometimes it is not about how cheap you get away getting something done... but I totally agree... I would use the cheapo thing and see if I can receive and decode with, for example, a Pixl.js... If radio is not BLE, then it become a bit more difficult - or cumbersome - though.

  • It probably is a waste of a Puck but its a way to support the project and have a bit of func tinkering.
    Getting a year out of the battery would be great. Probably only need the temperature to be accurate to within 5 minutes, if that would make any difference. Once the novelty has worn off I might reuse the puck for something else. Will have a look at the cheapo one as well. Might get both.

  • I was definitely not advocating buying something else instead of Puck. You can get both and use Puck for another interesting project :-) Or would you really get e.g. 3 Pucks to put them outside as 3 temperature sensors and keep them there for a year without tinkering with them? As with those LYWSD03MMC you can do that without too much thinking - and it could make sense to have more there e.g. to see how sunshine during day affect it in different locations.

  • Good point. I have bought 3. Do you have any code that reads the temperture onto a Bangle ? There is quite a big temperature difference between the floors in our house. Think I might use it to check the temperature upstairs that its not too cold in winter around bedtime. The puck will have to wait a bit - I'm really waiting for the new Bangle watch to go up for sale.

  • Do you have any code that reads the temperture onto a Bangle ?

    start here http://forum.espruino.com/conversations/­333218/#15882841

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Puck outside temperature sensor ? / battery life

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