The plantower devices were nice and small. But in the end I settled on the SDS011 simply because it can be connected to without soldering. In my use case - making it accessible to beginners - that was the most important factor.
I've also found that "how precise is it" doesn't matter all that much.
In a home you just want an indication. After a while you just start to think in about 5 levels, ranging from "bad" to ''great".
These cheap devices aren't precise enough to use in situations where you would care about precision, such as official measurements. So my recommendation is to forget about this.
@ahhk said:
Hi,
i searched a lot and read a lot about step-up and step-down converters in the last days, but i didnt find a really "good one" - and already soldered on pcb. Soldering is in general not a problem for me, except smd (i hate smd soldering). Has anyone a hint for a good booster (2xAA => 3.3V) or a step-down-regulator (3xAA => 3.3V) ?
Greetings
Andreas
How about this? http://www.ti.com/product/TPS82740B/description&lpos=Middle_Container&lid=Alternative_Devices
Welcome to the MySensors commmunity @thecricketer!
You would probably be better off minimizing power consumption of all components (see https://www.mysensors.org/build/battery for some recommendations and post a list of your components for more specific advice) but yes, what you are suggesting is possible.
Easiest way: use 2 2xAA battery holders. Connect + (red wire) of both holders to Vcc on the device and - (black wire) of both holders to gnd on the device. Done.
@mirodin said in How to power my sensors in a rental?:
using normally closed reed switches
You can "convert" those by reverting the orientation of the magnet on your door, then adding another magnet (weaker or further away) inside the node enclosure to keep the reed switch closed when you open the door. When the door is closed the reversed magnet on the door will open the reed switch.
To do even better you can use :
reed switches with 3 leads that work as both normally opened and normally closed switches, and wire them to the 2 interrupt pins. I used that on my first nodes and managed to get reeeeaaaally long battery life on a simple CR2032. When door status changes the node is woken up then you set pin low and current could run only a very short time, you send the message with new status then you activate the other interrupt pin and go back to sleep https://www.aliexpress.com/item/33028519094.html
if you're not afraid with SMD there are some ultra low power hall switches, using less than 1uA of current like the DRV5032.
Above question comes from a spam bot.
See: http://electronics.stackexchange.com/questions/235276/digital-circuit-to-compare-two-voltages/235279
(their bot seem to suck up questions from electronics.stackexchange.com, insert their links and post to forums)
If we see any more questions with Kynix-links, I'll just delete the new accounts. The @longkke user will be kept and banned for reference. I hope this will help other forums identifying Kynix as a SPAM cooperation.
