We have noticed that SDS011 sometimes stop sending data to ESP. It looks like it does not wakre up from sleep mode. Software restart does not help You need to cycle power off/on to get results again.
We have encountered that behavior when rewriting code reposonsible for SDS011 communication and assumed that is our mistake. However, we have spotted the same behavior in Sensor Communit kit, which was running on completley different software. As for now we believe it is some obscure error in SDS011 firmware.
We don't have way to change SDS011 firmware, so the only solution is to remove symptoms. Thus, hardware SDS011 restarer. This small module allows to cut power off from SDS011 only. When our NAMF detects no response from SDS011 cuts SDS011 power for few seconds bringing it back to live from sleep.
When installed according this manual, the restarer will collide with LCD (if Your NAM has one). You need to remove LCD or maybe find other way to install restarter.
In case You plan to use restarer when You solder NAM kit, then go directly to connecting SDS011
¶ Removing SDS011 from device
OK, so You need a restarer. You can buy it at any time and add to Your NAM.
First step is to remove SDS011. After openinig NAM case (disconnect power from NAM first!) unscrew 3 mounting screws shown on picture.
You don't have disconnect other senor connectors attached to I2C sockets, but it will be easier to operate. For clarity we show pictures without any other sensors attached.
After removing screws grab SDS011 by its edges and pull it from connector socket. You need to apply some force, there is thight with space, but it should not make any problems with pulling it off.
If Your NAM is PRO versions, with external antenna, watch out for not to pull external antenna cable, which may go over SDS011.
¶ Connecting SDS011 with restarter
Instead of use 6 pin femal header use cable which is included with restarter. It has two different plugs, only one matches SDS011 socket. It has polarity protection, so You can not plug it in wrong direction (at least not without hammer).
Screw SDS011 back on spacers. SDS011 cable will be pushed to the case wall, but there is enough space for it.
Plug restarter module into EXT socket. Watch carefully its orientation it does not have polarity protection. Do not plug it in wrong direction.
¶ NAMF setup
After connecting restarter does not work - it provides power and communictaion with SDS011 but NAMF does not know that can restart SDS011.
Visit Status page on sensor (/status) - check if 0x26 is listed on seen device addresses on I2C bus. If it is, then You need enable restarer in SDS011 config. Navigate to config page (/config), in
To check restarter statistics go to /status page and look in SDS011 section:
First field is how many times readings from SDS011 failed. Nonzero value does not mean automatically that there is real problem with SDS011.
Second filed - how many times restarter had cycled power for SDS011.
Third filed - value other than zero means that are some problems with communication between ESP and restarter.