How many ports devices?

[gandalf]

Hi guys 
I'm evaluating robo-tank as management system for my tank.

If I understood properly, this kit is the most feature-complete one: https://www.robo-tank.ca/Reef-pi-DI...luxe-Aquarium-Controller-AC-Power-Bar-PCB-Kit

is this true ?

Can someone tell me how many device I can plug with this kit ?

I'll be able to plug:

- 6 dosing pumps
- 8 AC outlet (I need 220v universal outlet)
- 3 temperature probes
- 2 pH probes
- 1 feeder
- 1 stepper motor for zeolite automatic wash (like the automatic zeovit filter from korallenzucth)
- 1 stepper motor for cleaning skimmer (could be useful)

What else ? As I'm still new in reef-pi, robo-tank and marine aquarium tank , I don't know if I need more devices to connect.

Can I expand robo-tank adding multiple expansion boards ? If yes, which boards are available and which ports will add ?

Any idea/suggestions ?

---

If I understood properly, robotank deluxe as 2 db9 ports, so I can plug up to 2 expansion board.
One expansion board is the AC power outlet, but If I use the "Robo-Tank PCA9685 Expander", I can connect 2 AC power outlet board (16 AC outlets) to the PCA9685 expander and the PCA9685 to the robotank deluxe via I2C port. doing this, will keep free both db9 ports on the deluxe board.

In that case, I can plug 2 additional expansion boards directly using the db9 ports on the deluxe board.

But can I daisy-chain the PCA9685 boards to increase the ports even more ? PCA9685 can also connect to other expansion boards like this: https://www.robo-tank.ca/Reef-pi-Pl...ion_2_DC_Ports_6_Sensor_Ports_Fully_Assembled or just to AC power outlet ?

 

[Rob F]

Hi Gandalf, thanks for your interest, all my controller kits get you the same in the end however I'm going to have an updated controller in a few days, here's info on it.

https://www.robo-tank.ca/forum/Thread-Robo-Tank-2-0-Updated-Controller

You can connect the list you have except no stepper motors, it's possible to DIY later but no point until reef-pi can control them. Today you can only use regular dosing pumps.

You understand the expansions and you could daisy chain multiple pca9685s to get even more ports. The pca9685 only has outputs so you can't read sensors only the outputs on the extensions I have would work. The two DB9 pins can be configured for input or output that's why I recommend moving power bars to the pca9685.

 

[gandalf]

Thank you for the reply. I'm not in a rush so i can wait for the new controller.
Are stepper motor dosing pumps better than the standard 12/24v ? In which way ?

Any limits in number or AC outlets and DC outlets using the extension in a dasy chain ?
How to add more sensors ? is this possible?

In other words, can I know the upper limits of robotank or, by using multiple expansion, I can grow with no limits ?

 

[Rob F]

Stepper motors are definitely better in general. If it's ok to slightly over/under dose than the extra expense probably isn't worth it but if you want accurate doses steppers are better. Stepper motors move based on steps, typically motors are 200 steps per revolution. The code says turn 200 steps and you'll always get one perfect rotation. With standard motors you can only say turn on for 1.5 seconds but that could be more or less depending on the motor. Some have more friction or maybe voltage is slightly lower/higher to that pump so the time it spins will be effected. With steppers in theory you could have one motor adding water to a reservoir and another draining it at the same rate and it would stay synced, with standard motors that's impossible.

To add steppers it's quite easy, you connect the stepper driver to 2 GPIO pins but at this time reef-pi doesn't talk to them. If you are comfortable with code it's something you could add but otherwise not.

I say you can run up to 3 pca9685 expansions however it's possible to run more. These connect via the I2C bus, this signal type hates cables though so it's very important to keep I2C wires between controller and pca9685 as short as possible, ideally 6" between devices. With that said it's possible to add I2C buffers to increase the signal strength to add more. As this is DIY based there's technically no limit but things can get unreliable if you add to much without proper circuits. Reef-pi technically has no limits but I have heard that CPU usage can go up the more reef-pi is running but I think the limits are quite high.

Sensors need input GPIOs, if you used DB9's you can add 16 extras + the 6 on controller, 21 total. Reef-pi does have a driver for ADS1015 which would allow more however this again is I2C so you can't get carried away.

pH you can run multiple circuits however I2C again.

 

[gandalf]

I'm a professional programmer, so adding code (still not saw the reef-pi or robo-tank code, I don't know the laguage used) should not be an issue, after knowing how the system works and yes, I need stepper motors pumps. So I have to wait for reefpi (is this on a todo list?) or I have to add it on my own. Doesn't require any stepper motor driver ? Hardware-side is everything ready ?

If I keep 6'' cables between the main controller and the extension boards, I'll be able to get 21 GPIO ports via I2C ?

 

[Rob F]

You might be able to add it then. reef-pi is GO and I use c++. Here's reef-pi code.

https://github.com/reef-pi/reef-pi

You can download mine from 2nd post in this thread. I will be adding stepper motor control, it's pretty easy to add.

Hardware isn't ready for stepper motor, you need to add the driver, this is how it's done. At some point I'm going to have an extension that plugs into the DB9 that will work with stepper motors.

https://makersportal.com/blog/raspberry-pi-stepper-motor-control-with-nema-17

With what I offer you can only get a maximum of 18 sensor ports, that's using two of the 6 sensor 2 DC extension. If you DIY and hack a bit you can add 4 more.

With the pca9685 expansion you can daisy chain two with 6" cable and get 32 outputs for things like AC outlets, DC ports or LED drivers as it's 0-5v PWM on each output. That frees up the DB9's for the sensor extensions.

 

[gandalf]

Ooooooooook, so, i'm almost ready to buy.

1) should I wait for the new controller version ? Any ETA ?
2) which raspberry should I buy and which one is suggested ?
3) can you tell me the most feature-complete system that I have to buy ? I know for sure I need 12-18 AC outlets. (european)
4) if possible, i would like to buy in steps, so, should I start with the base controller and then add more expansion boards ? PH and temps are the most important one to me, because I don't have any ph sensor currently and my temp sensors are not "smart", so i would like to replace these 2 asap.
5) i'm able to solder, so i prefere to buy the DIY kit.
6) i would like to put a touchscreen on my tank cabinet. Which screen is supported ? which one shoul I buy ?

 

[Rob F]

1) Sounds good, I think you might have to wait for next batch of new controllers, they should be arriving end of this coming week or beginning of next, they have been ordered.

2) They just releases a new Raspberry Pi Zero 2 W, I think I might start recommending this one. Apparently it has the same power as the Pi 3, only downside is no Ethernet plug but a person could add a $15 USB to Ethernet adapter if needed. I was recommending the Pi 3.

https://www.raspberrypi.com/products/raspberry-pi-zero-2-w/

3) As you noticed the universal AC power bar only has 6 outlets due to the size so you only get 12 outlets using the pca9685 expansion, if you use two pca9685 expansions you can plug in up to 4 power bars or 24 outlets. You need those and then up to 2 extensions, either the 6 DC / 2 Sensors or 6 Sensors / 2 DC. You can only connect two.

4) You can buy things as you build out, the controller does have the pH so you don't need any extensions to get some of everything running. Not sure what you mean by smart temp sensors? Reef-pi is compatible with the DS18B20's.

5) I do have a decent manual showing how to assemble the controller so if you're comfortable soldering you should be ok.

6) I've personally never used a touchscreen on the Pi but it sounds like you want HDMI touchscreen, stay away from official Raspberry Pi displays with the ribbon cable. This one has been verified to work however I don't know it'll work with the Pi 2 w I linked above. It only has one microUSB cable, this display uses regular USB for touch, will a converter work, I don't know. Might want a Pi 3 to be safe.

https://amzn.to/3nKP7De

Hope that helps some.

 

[gandalf]

3) As you noticed the universal AC power bar only has 6 outlets due to the size so you only get 12 outlets using the pca9685 expansion, if you use two pca9685 expansions you can plug in up to 4 power bars or 24 outlets. You need those and then up to 2 extensions, either the 6 DC / 2 Sensors or 6 Sensors / 2 DC. You can only connect two.

this is not clear. with 2 pca9685 expansion i can plug 2 power bar in each one, for a total of 24 AC outlets. why i need the 6dc/2sensor or 2dc/6sensors board? also, the sensors board can not be connected as db9 plugs are busy with the pca9685 boards...

 

[Rob F]

Sorry I should have reread the previous messages, I was thinking you needed 21 sensors as well that's why I mentioned the 2 dc / 6 sensor extensions. If 6 water sensor ports is enough you don't need those.

The pca9685 expansions don't plug into the DB9's, they use the I2C port. If you only want to expand the AC outlets you only need one pca9685 as two power bars can use the DB9's on controller. If two power bars is enough to start you can get the pca9685 when you add extra power bars.

 

[gandalf]

So, 1 pca9685 plus 2 power bar means 12 AC outlet. What if I need 18 (and A LOT of sensors) ?

 

[Rob F]

Well that all depends, this is what you get without any extensions / expansions.

• 12 AC outlets (2 power bars using DB9's on controller)
• 6 DC ports
• 6 Water sensors
• 2 Temp sensors (multiple sensors can be added to each port if necessary)
• 8 PWM / Analog ports (It is possible to connect a power bar to 6 ports)

The absolute maximum water sensors is 18 and requires two "2 DC / 6 Sensor" extensions. That's 12 extras + 6 defaults.

If you go extra water sensors you need 1 pca9685 to continue running the 2 power bars.

If you want 3rd power bar you need 1 more pca9685 and it'll have room for a 4th. Again if you don't use the 8 PWM ports you can connect a power bar to them and you wouldn't need the extra pca9685.

 

[gandalf]

so, if I understood properly, I can directly connect the power bar to the controller, using the DB9 port on the controller.
to keep that port free for other expansions, I can use a pca9685 between powerbar and controller. PCA expander will connect to controller with i2c, and power bar will be connect to the PCA expansion with one DB9. There are 2 db9 ports on the expansion, so i can use 2 power bar connected to a single pca expansion and still have the controller DB9 port available.

but I don't see the i2c plug on the controller....

Anyway, I don't think I need so many expansion, what I need for sure are 12/18 AC outlets and about 8 dosing pumps (just to be sure). I saw that kamoer has a dual-gear dosing head that is able to dose 1.3ml/minutes (0.02 ml per seconds), this should be compatbile with robo-tank, right ? Which is the minimum dose amount ?

2 or 4 temp sensors would be more then enough
2 or 4 water sensors is enough too
2 ph Probes (one for the calcium reactor, one for the tank)

What about redox probe ?

With PWM what should I do ? I don't plan to connect my lamps to robo-tank. Any other common device needs PWM ?

So: - power bars, temp sensors, water sensors and dosing pumps, I don't see any other requirements.

Another question: is possible to use custom AC outlets ? The stock one are HUGE, I really prefere to use some italian outlets.

How to connect multiple temp sensors to the same port ?

---

Also, the deluxe kit needs the pH circuit (this: https://www.robo-tank.ca/Reef-pi-Plug-and-Play-Hardware/Robo-Tank-Isolated-pH-Circuit-Arduino-PI) or just the probe because the circuit is integrated ?

When buying, in the configurator, shoud I choose 6 universal AC outlet or just one ?

 

[Rob F]

Yeah you have the DB9's correct. The I2C port is there, it's the 4 header pins right about the Robo-Tank name on top of controller. I ship the pca9685 expansion with header cable so it plugs in.

If you want 8 dosing pumps you will need an extension to get more DC ports, controller only has 6. If the dosing pump is 12v or 24v it'll work. Reef-pi will let you run it for as little as one second whenever you need.

You only need a pH probe, the circuit is built in. If you want 2nd pH probe you need another pH circuit like you linked.

Redox probes aren't compatible.

You'll probably just not use the PWM channels.

You can DIY AC power bar but you'll need to figure out, it's the same as Arduino if that helps.

To connect multiple DS18B20 to same plug just requires adding two as you would with one.

You only need to select 1 option for universal AC power bar, it's $6 more than a US power bar.

 

[gandalf]

if i understood properly, this cart allow me to connect 2 temp sensors, 2 phprobe , up to 12 dosing pumps , 12 AC outlet with 2 power bar connected to the expansion.

i Just have to add the probes (temp, pH, ...) and one or more 12/24v dosing pump

any EU reseller? for shipping cost and custom....

 

[Rob F]

That list will do exactly what you expect.

For powering things up you have a few options.

• Single 12v or 24v power supply, this would power up controller and the DC extension, you would need a Y cable or whatever.
• 12v power supply for controller giving you 6 DC ports at 12v and 24v power supply for DC extension giving you 6, 24v ports. You can flip power other way as well.

You'll also need 3 DB9 male to female straight through serial cables and of course the Raspberry Pi.

I do have a problem today though, I only have 6 universal outlets left, more were shipped to me Oct 28 but I'm not sure when they will arrive. I'm expecting any day but the tracking hasn't updated so I'm a little worried it could be another week or two or more.

Don't have any resellers at this time, I've had interest but not ready yet, maybe next year. Custom fees is definitely something to consider, sorry I do need to send an invoice as they can just throw package to corner and it feels like things are getting more strict. What they will charge is any ones guess, I've heard 0% - 40% from various people.