My Reef-Pi build thread

[bishoptf]

Yes, they share the same data line. Does using one sensor alone work? Can you confirm that you have enabled 1-wire in the /boot/config.txt file (using the pico board example has the 1wire support turned on)?

+1 on this, have you enable 1-wire for the pi?

not sure I would have done a rpi-update, that loads the latest raspberry firmware, may or may not be better...

 

[Bigtrout]

Can I ask whay sensors you bought? And where from?
Some of the china cheapies may not have the color coding correct.

 

[Bigtrout]

What is the result of running this command on command line:
lsmod

 

[theatrus]

Some things to check:

- You haven’t defined pin 4 as an inlet or an outlet anywhere
- As mentioned, sometimes the wire color codes can be just messed up.
- Make sure the dtoverlay command in config.txt is present and not commented out. (https://github.com/blueacro/reefpi-pico/blob/master/config.txt#L9) I don't think this is it, as you see 1wire master logs from dmesg.

Do you have a oscope or logic analyzer available? If the kernel is moving the data line around it would help rule out some class of issues.

 

[Ranjib]

one wire is enabled, esle he wont see the /sys/bus/w1 directory. Here is the content of my pico board based controller's /boot/config.txt

dtparam=i2c_arm=on
dtparam=spi=off
dtparam=audio=off

dtoverlay=pwm-2chan,pin=18,func=2,pin2=13,func2=4
dtoverlay=w1-gpio
dtoverlay=i2c-rtc,pcf8523

my temp sensor is working fine. the controller is running for more than a month now continuously without any hiccup

 

[dmolavi]

Yeah my config.txt has all that in it. The sensors are DROK sensors from Amazon. Red (vcc), white (gnd) and yellow (data) wires.

Is there another recommended sensor manufacturer? The DROK were nice because they are crimped and waterproof.

I don't have a scope available unfortunately.

 

[dmolavi]

What is the result of running this command on command line:
lsmod

lsmod does show the w1-whatever that's needed. The driver is loaded, since its shown as such in the dmesg output.

 

[dmolavi]

Some things to check:

- You haven’t defined pin 4 as an inlet or an outlet anywhere
- As mentioned, sometimes the wire color codes can be just messed up.
- Make sure the dtoverlay command in config.txt is present and not commented out. (https://github.com/blueacro/reefpi-pico/blob/master/config.txt#L9) I don't think this is it, as you see 1wire master logs from dmesg.

Do you have a oscope or logic analyzer available? If the kernel is moving the data line around it would help rule out some class of issues.

Wrt pin 4, the temp probes are the first thing I'm trying to get working, so no other inlets or outlets have been defined.

 

[Bigtrout]

If everything is loaded software-wise to read the probes, then we are back to wiring issues. If you have checked continuity throughout and the probes are still giving you nothing, there remains the possibility that they are miswired internally and the color codes wrong.

 

[dmolavi]

If everything is loaded software-wise to read the probes, then we are back to wiring issues. If you have checked continuity throughout and the probes are still giving you nothing, there remains the possibility that they are miswired internally and the color codes wrong.

How can I check the internal wiring on the probes?

I can see 3.3v between VCC and ground on my protoboard at each sensor connection. I also see 3.3v between data and ground but I assume the bus speed is just too fast for my multimeter so it always reads high.

 

[Bigtrout]

How can I check the internal wiring on the probes?

I can see 3.3v between VCC and ground on my protoboard at each sensor connection. I also see 3.3v between data and ground but I assume the bus speed is just too fast for my multimeter so it always reads high.

Does your multimeter have a diode check mode?

 

[dmolavi]

Does your multimeter have a diode check mode?

It does. Yes.

 

[Bigtrout]

To check the DS18B20 with a multimeter, choose the "diode testing" mode, and put the positive testing lead to the white wire (GND) of the sensor. The voltage between white wire (GND) and the red wire (VDD) should be around 0.59V ~ 0.63V; the voltage between white wire (GND) and the yellow wire (DQ) should slightly lower, around 0.49V ~ 0.55V.

This is something i found online that may help.

 

[dmolavi]

This is something i found online that may help.

Thanks. I'll give that a go.

 

[Bigtrout]

Thanks. I'll give that a go.

I didnt catch that you are using the Drok sensors, with the red silicone insulation
Ok the ds18b20 color codes on mine were vcc=red, gnd=white and data=yellow
Double check the jack/audio connection as well if you can

 

[dmolavi]

This is something i found online that may help.

Hmm here's what I get:
Multimeter ground on probe white to multimeter high on probe red - OF

Multimeter ground on probe RED to multimeter high on probe WHITE - 0.60v

Same with the data wire, with mm ground on white, it read OF. With mm ground on yellow (mm high on white) I get 0.51v.

Does this mean the probe wiring is backwards?

 

[Bigtrout]

Hmm here's what I get:
Multimeter ground on probe white to multimeter high on probe red - OF

Multimeter ground on probe RED to multimeter high on probe WHITE - 0.60v

Same with the data wire, with mm ground on white, it read OF. With mm ground on yellow (mm high on white) I get 0.51v.

Does this mean the probe wiring is backwards?

Hmm here's what I get:
Multimeter ground on probe white to multimeter high on probe red - OF

Multimeter ground on probe RED to multimeter high on probe WHITE - 0.60v

Same with the data wire, with mm ground on white, it read OF. With mm ground on yellow (mm high on white) I get 0.51v.

Does this mean the probe wiring is backwards?

Im thinking yes but before we do anything else, i have a spare laying around, let me check for sure on mine.

 

[dmolavi]

Im thinking yes but before we do anything else, i have a spare laying around, let me check for sure on mine.

Thanks

 

[Bigtrout]

Thanks

No its not the probe itself being miswired.

On a working sensor(plugged it into reef pi to make sure it works, then unplugged to test)

MM+ on WHITE
MM- on RED
.63volts

MM+ on WHITE
MM- on YELLOW
.53volts

So, your sensors test good and color codes are correct...now time to look elsewhere

 

[dmolavi]

No its not the probe itself being miswired.

On a working sensor(plugged it into reef pi to make sure it works, then unplugged to test)

MM+ on WHITE
MM- on RED
.63volts

MM+ on WHITE
MM- on YELLOW
.53volts

So, your sensors test good and color codes are correct...now time to look elsewhere

Grr I was hoping it was something simple