pm2.5 sensor SEN0177: concentration shows 0, density is low- DFRobot Forum

2016-08-09 19:27:12 Ok, I contacted again with our supplier waiting for the firmware. Leff

2016-08-06 01:41:30 Unfortunately the readings went back to zero again.
I'll leave this now and will try to write the firmware if this is possible. hb9tmc

2016-08-05 22:59:22 Really? So it's the matter about the photodiode fake soldering? Leff

2016-08-04 23:11:53 Now that's support, than you

Ok, I already wondered why they have a RX pin. The device is functioning well, as far as I can tell. The laser works, the photodiode works. Just the output is wrong.

Yes, I have the adapters.

Thanks,
Stef

edit:
I've resoldered the photodiode because the soldering joints didn't looked too good on a close inspection. Now the values seem pretty normal. hb9tmc

2016-08-04 23:11:53 Now that's support, than you

Ok, I already wondered why they have a RX pin. The device is functioning well, as far as I can tell. The laser works, the photodiode works. Just the output is wrong.

Yes, I have the adapters.

Thanks,
Stef

edit:
I've resoldered the photodiode because the soldering joints didn't looked too good on a close inspection. Now the values seem pretty normal. hb9tmc

2016-08-04 08:21:20 I just checked the shipping costs; sending it back to HK would cost almost as much as a new one.
Schematic would be helpful though. hb9tmc

2016-08-04 00:16:52 Hi,

Many thanks for your pictures, it's very helpful. I am waiting for the supplier's reply. I will keep you updated no later than next Monday. Hope you could understand. Leff

2016-08-02 23:48:49 Yes, the sensor was working well. I've included a diagram in the gallery as well as photos from the PCB:
http://imgur.com/a/sQGTH

After disassembling and putting it back together (without changing anything) the readings are now higher than zero, but still too low (3-4µg/m³).

I found some more pictures and experiences here:
http://aqicn.org/sensor/pms1003/de/ hb9tmc

2016-08-02 19:34:57 Hi hb9tmc,

To blow to it can not change much about the dust density I am afraid. Anyway, generally speaking, the air can not be as fresh as ZERO :shock:

My question is: do you mean it worked well several days ago, but now, it always display 0,0,0, right?

I am not sure whether you would lose the warranty if you open the sensor, I have to check with our supplier. BTW, can I have a picture about the sensor after you opened its shell? Leff

2016-08-02 19:34:57 Hi hb9tmc,

To blow to it can not change much about the dust density I am afraid. Anyway, generally speaking, the air can not be as fresh as ZERO :shock:

My question is: do you mean it worked well several days ago, but now, it always display 0,0,0, right?

I am not sure whether you would lose the warranty if you open the sensor, I have to check with our supplier. BTW, can I have a picture about the sensor after you opened its shell? Leff

2016-08-02 01:51:42 Hi,

I have been running the SEN0177 dust sensor for some days. Today when i started it up, the three concentration data fields (PM1, 2.5 and 10) were 00 00 00, while the density fields are relatively low, example for the 31 bytes after the start byte:

Code: Select all

4D 0 1C 0 0 0 0 0 0 0 0 0 0 0 0 0 39 0 13 0 3 0 0 0 0 0 0 51 0 1 4B
4D 0 1C 0 0 0 0 0 0 0 0 0 0 0 0 0 39 0 13 0 3 0 0 0 0 0 0 51 0 1 4B 
4D 0 1C 0 0 0 0 0 0 0 0 0 0 0 0 0 39 0 13 0 1 0 0 0 0 0 0 51 0 1 49
4D 0 1C 0 0 0 0 0 0 0 0 0 0 0 0 0 36 0 12 0 0 0 0 0 0 0 0 51 0 1 44
4D 0 1C 0 0 0 0 0 0 0 0 0 0 0 0 0 36 0 12 0 0 0 0 0 0 0 0 51 0 1 44

The checksums are correct, so the sensor is giving wrong values. What can I do about that?
When I blow into the aperture, sometimes there are concentration readings for some seconds but then they go back to 0 again.

Do i lose warranty if I open the sensor? There is maybe just something stuck in the refraction chamber. hb9tmc