Disappearing DS18B20 temperature probe

[kdx7214]

I currently have two of the DS18B20 probes. The first one randomly stopped showing up on the bus after weeks of working correctly. I realized it tonight and replaced it with the other probe. The probe showed up on the bus for 2-3 minutes, then disappeared. Any idea what would cause this? The first probe worked just fine for a while and a physical inspection shows no obvious problems. I've triple checked the wiring and that all looks just fine.

Shouldn't make any difference, but this is on a robo-tank controller.

 

[robsworld78]

I currently have two of the DS18B20 probes. The first one randomly stopped showing up on the bus after weeks of working correctly. I realized it tonight and replaced it with the other probe. The probe showed up on the bus for 2-3 minutes, then disappeared. Any idea what would cause this? The first probe worked just fine for a while and a physical inspection shows no obvious problems. I've triple checked the wiring and that all looks just fine.

Shouldn't make any difference, but this is on a robo-tank controller.

Hi, sorry you're having trouble. Any chance you have any AC cables next to the sensor cable? It's possible it's bad sensors or noise is getting in through them. It might be worth trying these sensors as they are shielded, I know someone who had similar issue and updating to these sort it out. If you got the sensors from me I can help as I have a feeling my last couple batches haven't been the best. I think I may need to start getting these ones as well.

2 PCS/LOT DS18B20 High Temp Sensor 3 meters Waterproof Thermometer Sensor -55 ~125 Celsius Degree Thermometer Probe

It is a 3 meters Thermometer Sensor/Temperature Sensor, Type : DS18B20 high temp sensor,Silicone shielded Cable, Measurement range : -55°c to 125°c (-67℉ to 257℉), Power Supply Range: 3.0V~5.5V, Suitable for Thermometer/Digital Thermostat etc. Parameters: Type : DS18B20 high temp sensor,Si

www.droking.com

 

[kdx7214]

Hi, sorry you're having trouble. Any chance you have any AC cables next to the sensor cable? It's possible it's bad sensors or noise is getting in through them. It might be worth trying these sensors as they are shielded, I know someone who had similar issue and updating to these sort it out. If you got the sensors from me I can help as I have a feeling my last couple batches haven't been the best. I think I may need to start getting these ones as well.

2 PCS/LOT DS18B20 High Temp Sensor 3 meters Waterproof Thermometer Sensor -55 ~125 Celsius Degree Thermometer Probe

It is a 3 meters Thermometer Sensor/Temperature Sensor, Type : DS18B20 high temp sensor,Silicone shielded Cable, Measurement range : -55°c to 125°c (-67℉ to 257℉), Power Supply Range: 3.0V~5.5V, Suitable for Thermometer/Digital Thermostat etc. Parameters: Type : DS18B20 high temp sensor,Si

www.droking.com

I'll order some of these today and see if they help. The two that I had I'm fairly sure I got from Amazon. It's very weird though. I can initially connect it and the Pi will see it on the bus for 2-3 minutes. Usually just long enough for me to get it configured in reef-pi and get one or two measurements, then it disappears from the bus. It's not near any other cables, but could still be interference of some sort or other.

On another note, I have two suggestions for you for robo-tank. First, and this one is a major amount of work, would be to swap the two RJ45 connectors on the sensor unit. Right now if you set these two units flat, the cables always cross which just doesn't look all that good. Not a major deal, but if you find yourself doing major rework of the pcb it's worth considering. Second, there's no mention in the docs of good ways to mount robo tank on a stand or anything. I hesitate to take it apart, drill a hole, and reassemble for fear of hitting something vital. Still not quite sure how I'm going to go about it lol.

Thanks!


Edit: I had a couple of other connectors with the same plug configuration and decided to try one of them on a lark and it worked. I suspect there are some faulty green 3-conductor plugs in the kit.

 

[Ranjib]

I do not know why, but my probes too get bad some times. Every once in a while, sometime after working for 3-4 years they die. Generally they give erroneous reading (185F for example) before going out completely. I can not attribute these failures to any visible physical damages.

 

[robsworld78]

I'll order some of these today and see if they help. The two that I had I'm fairly sure I got from Amazon. It's very weird though. I can initially connect it and the Pi will see it on the bus for 2-3 minutes. Usually just long enough for me to get it configured in reef-pi and get one or two measurements, then it disappears from the bus. It's not near any other cables, but could still be interference of some sort or other.

On another note, I have two suggestions for you for robo-tank. First, and this one is a major amount of work, would be to swap the two RJ45 connectors on the sensor unit. Right now if you set these two units flat, the cables always cross which just doesn't look all that good. Not a major deal, but if you find yourself doing major rework of the pcb it's worth considering. Second, there's no mention in the docs of good ways to mount robo tank on a stand or anything. I hesitate to take it apart, drill a hole, and reassemble for fear of hitting something vital. Still not quite sure how I'm going to go about it lol.

Thanks!


Edit: I had a couple of other connectors with the same plug configuration and decided to try one of them on a lark and it worked. I suspect there are some faulty green 3-conductor plugs in the kit.

There you go, nice find. I wouldn't have thought that as I don't think I've seen a bad one before but I should have mentioned it can be a problem sometimes by cutting the wire where it's crimped so poor connection. As it's the connector there's probably a pin not making contact, glad you were able to find it. If you ever need more connectors let me know.

I did notice the RJ45's should be flipped, at some point I will sort that out. I'm also considering replacing the two RJ45's on the equipment extension for an HDMI as it has enough conductors for everything. I like two though as it gives more flexibility. I assume you would prefer if it was just one cable?

I think when you got the controller I didn't have any bracket but I have one now, this is the style of it. If you don't have the 6 holes in each lid you'll need new lids. If you have a printer I can send the files or I can print some out for you.

Robo-Tank 3.0 for reef-pi

Not directly, steppers are usually controlled by a few configuration pins (enable, microstep select, etc) and pulses on the STEP pin. I'm happy to collaborate on a simple USB to stepper control firmware (or USB to X). Got a partial reel of SAMD11s which would be plenty of horsepower for this...

www.reef2reef.com

 

[kdx7214]

There you go, nice find. I wouldn't have thought that as I don't think I've seen a bad one before but I should have mentioned it can be a problem sometimes by cutting the wire where it's crimped so poor connection. As it's the connector there's probably a pin not making contact, glad you were able to find it. If you ever need more connectors let me know.

I did notice the RJ45's should be flipped, at some point I will sort that out. I'm also considering replacing the two RJ45's on the equipment extension for an HDMI as it has enough conductors for everything. I like two though as it gives more flexibility. I assume you would prefer if it was just one cable?

I think when you got the controller I didn't have any bracket but I have one now, this is the style of it. If you don't have the 6 holes in each lid you'll need new lids. If you have a printer I can send the files or I can print some out for you.

Robo-Tank 3.0 for reef-pi

Not directly, steppers are usually controlled by a few configuration pins (enable, microstep select, etc) and pulses on the STEP pin. I'm happy to collaborate on a simple USB to stepper control firmware (or USB to X). Got a partial reel of SAMD11s which would be plenty of horsepower for this...

www.reef2reef.com

Each of the back plates has 6 holes in it, closer to one end than the other. I don't have a 3d printer yet, that's something the wife and I have wanted to do, but don't know enough about them to pick a cheap one to start with. If you can recommend one and the spool I can try to do it myself, or if you wish, charge my card for the shipping/labor and ship me the brackets (in blue please lol). Either is cool with me, but I do want to get a 3d printer, so this might be a good time :)

 

[robsworld78]

Each of the back plates has 6 holes in it, closer to one end than the other. I don't have a 3d printer yet, that's something the wife and I have wanted to do, but don't know enough about them to pick a cheap one to start with. If you can recommend one and the spool I can try to do it myself, or if you wish, charge my card for the shipping/labor and ship me the brackets (in blue please lol). Either is cool with me, but I do want to get a 3d printer, so this might be a good time :)

All you need is the bracket, we can do either, your call but I am out of blue. For a printer a Creality Ender 3 might be a good start, I don't have that model but I hear lots of good things about it and it doesn't break the bank.

Amazon.com : creality ender 3

 

[kdx7214]

All you need is the bracket, we can do either, your call but I am out of blue. For a printer a Creality Ender 3 might be a good start, I don't have that model but I hear lots of good things about it and it doesn't break the bank.

Amazon.com : creality ender 3

We just ordered one of the Creality Ender 3 and some blue PET filament. Are the plans for this on your site or if not, could you email them to me?

Thanks!

 

[robsworld78]

We just ordered one of the Creality Ender 3 and some blue PET filament. Are the plans for this on your site or if not, could you email them to me?

Thanks!

Right on, you should have fun with that. You might want to start with PLA filament as it's the easiest to use, I think PET needs more tuning. It might be a better experience if you can get a good print quick rather than deal with issues related to PET and not know it.

Here's a link to download the files, it's labeled "Wall mount and rails". Looking forward to hearing how it goes.

Robo-Tank 3D Printable Cases

A collection of Robo-Tank 3D printable cases for the reef-pi deluxe aquarium controller and accessories. Also various brackets for your favorite water sensors. Download STL and Sketchup Free design files.

www.robo-tank.ca