• RE: Raspberry Pi3 alternative?

    @bjacobse said in Raspberry Pi3 alternative?:

    @nca78
    I think you must have misunderstood the concept. I did not use a ethernet splitter and extra cable mess...
    I use my router as IP supplier, 1 ethernet cable to my RPI, so I have cable to my domoticz, the RPI gets IP via cable, and if the I'm not able to ping gateway (router) then there is no power as the gateway is down.
    the ONLY extra thing I have purchased is a the powerbank ๐Ÿ™‚

    Indeed I misunderstood, it makes much more sense like that ๐Ÿ™‚

    @zboblamont said in Raspberry Pi3 alternative?:

    Perhaps French, German and Dutch supplies are more reliable, but here in Romania, "Vorsprung durch fuckup" prevails

    Same here in Vietnam... That's why I'll also have a wifi gateway with battery backup soon.

    posted in Controllers
  • RE: Raspberry Pi3 alternative?

    @bjacobse said in Raspberry Pi3 alternative?:

    @nca78 said in Raspberry Pi3 alternative?:

    Do you also use the ethernet switch as a power sensor ? ๐Ÿ˜„ I would just use an USB splitter before the powerbank, then use one wire and a voltage divider to connect it directly to a GPIO...

    There are typically many paths to same solution ๐Ÿ™‚
    It was easiest for me to just copy exact same setup - why should I bother to purchase an USB splitter and spend time to setup a voltage divider and create a script that needed to measure voltage on a GPIO

    It's just that it looks like a serious overkill and cable mess to use an ethernet splitter + it's own supply + ethernet cable when it can be done with less than 1$ of hardware and only one splitter + one spare usb cable. But that's just my own opinion ๐Ÿ™‚

    And if you want to really go for cheap and easy solution the raspi ups hat (blue PCB like in the link below) works like a charm. Compact, efficient, no extra cable. And I think the price is even cheaper than powerbank + splitter.
    https://www.aliexpress.com/item/32882666003.html

    posted in Controllers
  • RE: Suitable long-term sensors for PM, Ozone and NO2

    @skywatch said in Suitable long-term sensors for PM, Ozone and NO2:

    @nca78 Thanks for the explaination - Now I understand that you require precision measurements whereas I just needed to know when the dust levels were rising in order to clean the room! ๐Ÿ˜‰

    Maybe in the future I'll go down another path, but for the time being I have more urgent nodes to make.

    Yes if you just need a dusty/not dusty detection, it will do the job.
    But you might breathe polluted air regularly and not know it. I live in a big city of a developing country and I need to be aware of what my family breathes.

    posted in General Discussion
  • RE: Raspberry Pi3 alternative?

    @alowhum said in Raspberry Pi3 alternative?:

    for about 15 minutes.

    Haha don't move to Vietnam, here when they cut power it can last half a day.

    @bjacobse said in Raspberry Pi3 alternative?:

    I use a RPI3 and use this UPS (powerbank + script), as it's cheap and useful
    http://raspi-ups.appspot.com/en/index.jsp

    Do you also use the ethernet switch as a power sensor ? ๐Ÿ˜„ I would just use an USB splitter before the powerbank, then use one wire and a voltage divider to connect it directly to a GPIO...

    posted in Controllers
  • RE: What did you build today (Pictures) ?

    @bjacobse said in What did you build today (Pictures) ?:

    @berkseo
    Clever idea to use SN74LVC1G00 as while both inputs are same voltage it only consume ICC = 10uA (10 mircoA) in whole voltage range 1.65V -5,5V

    Not when when you have a low power comparator available that runs with only 0.5ยตA...

    posted in General Discussion
  • RE: Pir AS 312 with 2 rechargeable AAA battery. Boost needed?

    @franz-unix said in Pir AS 312 with 2 rechargeable AAA battery. Boost needed?:

    About the noise question... yes this could be a problem, but the manufacturer declare the booster as "Low ripple and Low noise", and in my schematic (see below) I have inserted a dedicated capacitor for the PIR, so I hope this is enough.

    It's a PFM step up to be efficient with low loads, meaning the frequency of the noise will change a lot and it is much harder to filter. You might want to include on your PCB an option to go through a ldo (that you can of course bypass), so if the step up is too noisy you can use one with a bit higher output voltage and use the ldo to filter the output a bit more.

    But I agree with @rozpruwacz a li-ion battery with a ldo like XC6206 sounds like a way more simple option and it's also easy to make it more compact than with 2 AA/AAA.

    posted in Hardware
  • RE: Suitable long-term sensors for PM, Ozone and NO2

    @luxor said in Suitable long-term sensors for PM, Ozone and NO2:

    @nca78 Thank you so much! Do you have experience in Ozone and NO2 sensors aswell? I cant find so many different ones. Any suggestions on that side? Which are long lasting, which not?

    Sorry, I don't. I searched a bit and didn't see anything interesting at a reasonable price.

    posted in General Discussion
  • RE: Suitable long-term sensors for PM, Ozone and NO2

    @skywatch because:

    • it's using an IR led instead of a laser for the others, so it can't detect small PM sizes
    • it doesn't have a fan so airflow is not constant and measurements can't be accurate. It can be used only for relative measurement and not absolute ones.
    • it has analog instead of digital output adding even more imprecision

    It can't compare to any of the other models above, as they all have laser + constant air flow + calibrated digital output, giving a particle concentration at +/-10 or 15% that can be used to calculate a relatively accurate AQI

    posted in General Discussion
  • RE: Suitable long-term sensors for PM, Ozone and NO2

    Hello,

    @luxor said in Suitable long-term sensors for PM, Ozone and NO2:
    I have a few sensors in mind (for PM: SDS011, Plantower PMS 5003/7003, Sharp GP2Y1010AU0F, Honeywell HPM Series...) but since this is my first time doing this kind of stuff, I dont have any experience. Do you mind sharing your experiences with me? I would be happy for any help!

    I would go for the PMS7003 if you are interested in measuring different particulate sizes, HPM if you can deal with only PM2.5 and want some really long lasting sensor.

    • Sharp is bullshit so not a valid option.
    • PMS5003 and HPM share the same electronic but HPM has better quality/longer lasting fan and laser diode so there's no reason to take the PMS5003.
    • for SDS011 it seems good but I never tried it as it's too bulky for the sensor I'm designing and also the most power hungry so not convenient to unplug and move around while powered on battery.

    If it's in your budget (it's around 50 USD) you can also consider the Sensirion SPS30, it has the best accuracy, compact size (just a bit bigger than PMSA003), i2c interface and auto-cleaning feature and claims a 8 years lifetime.

    posted in General Discussion
  • RE: What did you build today (Pictures) ?

    @boozz said in What did you build today (Pictures) ?:

    @gohan
    I was referring to @berkseo 's situation and images/examples. I just wondered why this person would put this amount of effort in creating a device that would probably not be functional at the moment it should be functional. I'm just thinking about corrosion of the pcb, a drained battery, change of properties of the 'sensor' due to time-effects etc.
    Do not misunderstand me: I'm absolutely enthousiastic about this device (and I'm impressed by how small it is and the design), but I'm a bit concerned about the effects that could negatively affect the behaviour of it.

    You can see on the picture he already had a leak under his kitchen sink ๐Ÿ˜›
    And in some countries pipes installations are not very reliable, for example yesterday evening my dishwasher emptied on the floor because the workers did not glue the PVC pipe angle so it went away. Would have love to be warned at the first drops instead of realizing it much later when walking in water in the middle of the kitchen. I also had problem with drinkable water fountain not stopping when tank was full and emptying the 20l bottle on the floor, leaks of sinks and bathtub in the bathrooms in previous apartment, etc etc
    So there's truly a "market" for those sensors, they could also be slightly modified to make rain detection instead and warn you if rain is coming and some windows are still opened (very useful here in tropical weather when you can switch from sunny to tropical rain in a mater of minutes).

    And if you use the low power comparator of the nrf5 it uses only a few uA in sleep mode, easily detects a bit of water between the 2 contacts and can last for 1-2 years on button cell.

    posted in General Discussion