Confusion on pins and Pi2Grover connection for HM3301

I'm using the connector that the Pi2Grover specification diagram indicates is D20/D21. (Bottom row, 2nd from the left, looking at the board with the GPIO connector at the top.) The HM3301 tutorial looks like it's going to the D21/D26 connector, which is one of the sources of confusion. I put a print statement in the driver to verify it was using the expected values.

Here is the output of testSDL_Pi_HM3301.py, including my print statements. The first print is in the __init__ method for SDL_Pi_HM3301 and prints the arguments passed to it. The second print is the count and data vector from the call to self.pi.bb_i2c_zip() in read_HM3301_data().

<pipio.pi host=localhost port=8888> 21 20 128
-82 []
closing hm3301
Traceback (most recent call last):
File "testSDL_Pi_HM3301.py", line 21, in <module>
myData = hm3301.get_data()
File "/home/pi/SDL_Pi_SkyWeather2/SDL_Pi_HM3301/SDL_Pi_HM3301.py", line 85, in get_data
self.parse_data(data)
File "/home/pi/SDL_Pi_SkyWeather2/SDL_Pi_HM3301/SDL_Pi_HM3301.py", line 74, in parse_data
self.PM_1_0_conctrt_std = data[4]<<8 | data[5]
IndexError: list index out of range

testSDL_Pi_HM3301.py:

# test HM3301 Laser Dust Sensor

# must run "sudo pigpiod" before starting

import SDL_Pi_HM3301
import time
import traceback
import pigpio

mypi = pigpio.pi()

mySDA = 21
mySCL = 20

hm3301 = SDL_Pi_HM3301.SDL_Pi_HM3301(SDA=mySDA, SCL=mySCL, pi=mypi)
time.sleep(0.01)
try:
while 1:


myData = hm3301.get_data()
print ("data=",myData)
if (hm3301.checksum() != True):
print("Checksum Error!")
myAQI = hm3301.get_aqi()
hm3301.print_data()
print ("AQI=", myAQI)

time.sleep(3)

except:
print ("closing hm3301")
print(traceback.format_exc())
hm3301.close()

Okay, first, a few things about my set up: The processor is a Raspberry Pi 3A+. I am using VNC to remote into the Pi from my iMac desktop. I am putting together a "do-it-yourself" solar powered SkyWeather2 starting from the basic Weather Rack2. All of the other sensors are working fine. The HM3301 is from a Solar Wireless Air Quality Sensor kit. As you can see from the picture I sent, it's plugged into the Pi through the Pi2Grover board.I haven't tried getting the HM3301 working as part of the Solar Wireless Air Quality Sensor Kit, but I'm thinking of trying that next.

I am attaching 2 screenshots - one of the freshly booted system, and one showing the startup of pigpiod and testSDL_Pi_HM3301.py.

Thanks for your help,
chuck Barker

I'm getting the same sort of results:

sudo python3 testDustHM3301.py
./SkyWeather2.JSON File exists
b''
b''
<pipio.pi host=localhost port=8888> 21 20 128
-82 []
Traceback (most recent call last):
File "testDustHM3301.py", line 50, in <module>
myData = DustSensor.get_data()
File "/home/pi/SDL_Pi_SkyWeather2/DustSensor.py", line 146, in get_data
myData = hm3301.get_data()
File "./SDL_Pi_HM3301/SDL_Pi_HM3301.py", line 85, in get_data
self.parse_data(data)
File "./SDL_Pi_HM3301/SDL_Pi_HM3301.py", line 74, in parse_data
self.PM_1_0_conctrt_std = data[4]<<8 | data[5]
IndexError: list index out of range



I think I see what may be a problem. testDustHM3301.py tries to turn on the dust sensor using DustSensorPowerPin, but my only connections are through the single Grove connector. I don't don't have a separate power connection. Doesn't it get its power through the Grove connector? If not, how do I get power to it?

Yes, I tried what you suggested. I downloaded a fresh copy of the repository and got the same results using the testDustHM3301.py app - bad read from the HM3301 as if it wasn't there. Do I need to connect a separate pin for power?