Help with reef pi doser please

[Wayne1712]

Hi can someone help me with my reef pi doser build please.
I've followed several guides to build an eight pump doser but can't get it to work.
I've set the outlets and Jack's, added the equipment, set timers and programmed the dosing pump but nothing happens.

Also when I first power the raspberry pi up I get a pca9685 error, if I then close reef pi and open it again the error goes away.

View attachment 1121767 View attachment 1121769 View attachment 1121770 View attachment 1121771

 

[Wayne1712]

Last picture is the error I get when selecting rpi as the driver instead of pca

 

[Wayne1712]

 

[AquaRaider44]

I am not an expert here or anything but I have no clue what the heck you have built there. What I would do would be to scrap everything there and simplify this by 1000x. I would get a pca9685 connect that to the pi and then connect the pca9685 signal wires for the pumps to a ULN2803A. This way the pi tells the pca9685 to generate pwm signals for the dosers and then the signals which are at 3.3 or 5v get stepped up to 12v using the ULN2803A. I have a different doser setup but its almost identical for how to wire it simply. https://www.reef2reef.com/threads/reef-pi-the-all-in-one-pi-challenge.592733/ check out my build thread here.

 

[Wayne1712]

I've followed this guide as well as the main guide on adafruit, I need a doser with at least 8 pump and found this.
https://www.reef2reef.com/threads/a-reef-pi-that-can-run-up-to-8-dosing-pumps.563576/

 

[Michael Lane]

A couple of things look a bit off. I don't see a pca9685 in this pictures, do you have one outside of it somewhere? It looks like you actually have the proto hat wired with a motor driver instead of pca9685. If that's the case, the first step should be to configure reef-pi to use internal pwm. Once you get that working, we can move on to troubleshooting the rest.

 

[Ranjib]

Last picture is the error I get when selecting rpi as the driver instead of pca

There are many things going on here that I am not able to understand. Let’s take the, piece by piece. What those relays are used for? Are you using pca9685 or pi for pwm? The error you have shown is related to pi pwm. Make sure you enable it in /boot/config.txt, the first guide in adafruit has details. The other error is related to pca9685 not being detected. Make sure i2c is enabled and the chip is detected using i2c-detect command .

 

[Wayne1712]

Thanks for the reply, been a very long day today so haven't had time to get onto it.
The relays are connected to the pumps (I posted the wrong picture above).
I2c is enabled but I haven't tried to detect the chip yet.
I've got a lot more time tomorrow so will go through what you've mentioned above.
One of the pumps isn't connected to anything, just eight pumps, one to each relay.

 

[Wayne1712]

I have configured the rpi for pwm so that error is fixed, I have also disabled the pca9685 in the reef pi configuration menu.
Still getting the pca9685 error when I boot it up and still can't get it to work using rpi for the pwm

 

[Wayne1712]

@Ranjib ?

 

[Ranjib]

@Wayne1712 sorry i have missed this somehow, my apologies. which version you are using, i have fixed an rpi pwm bug in 2.5 .

 

[Wayne1712]

Thanks for the reply, no I haven't got it working yet.
My plan was to get it out today but the wife had other plans so ended up taking her and the kids to the beach.
I will be getting it out tomorrow though so will check which version I'm running.

 

[Wayne1712]

@Ranjib I have updated the software so am now running version 2.5 error free :)
I can get the doser working if I remove the relays and run it as your original design with just two pumps but can't get it working with the relays.

 

[Ranjib]

Can you share the schematic/circuit of your setup, it will be useful to understand why relays are not working

 

[Wayne1712]

I don't have a schematic of it, I followed your guide and another build in R2R.

 

[Wayne1712]

This is the build I followed

A Reef-Pi that can run up to 8 dosing pumps

I’ve been following Reef-Pi since late October 2018 when I started my planted freshwater tank. I had been looking for a controller system and luckily found Reef-Pi. I have no coding experience and very limited knowledge of electronics. I spent last winter season “dabbling” with Raspberry...

www.reef2reef.com

 

[DaveWasabi]

Hmm, I've checked it, seems a bit complicated as well.

 

[Wayne1712]

@Ranjib ,sorry for the late reply, have been on holiday.
I've put a diagram together which I hope explains how the relays and pumps are wired to the proto board.

 

[Ranjib]

@Ranjib ,sorry for the late reply, have been on holiday.
I've put a diagram together which I hope explains how the relays and pumps are wired to the proto board.

Remember uln2803a is a sink type driver, I.e. you have to connect the negative end of relays in uln2803a output pin. I don’t know if the relay will work in such configuration, for adj powerstrip it worked, but I have not tested with raw relay boards like yours. In short, I think you have to reverse the wiring and connect the positive (5v ..) to the gnd pin and connect the uln2803 output pins to individual relay pins.

 

[Michael Lane]

It may be harmful to reverse the polarity on the relay driver board since it is using optoisolators. These relay boards sometimes have a jumper that can switch them from active high to active low.