reef-pi :: An opensource reef tank controller based on Raspberry Pi.

[Marc Kruithof]

@MaccaPopEye and others

https://www.littlebirdelectronics.com.au/8-channels-5v-relay-module
Now that I know which board you use, I think I can advise you a bit more. Looking at the schema of your board, it uses transistors to drive the relays. Nice. This solves a lot for you. A bit pitty is that they use leds directly on the input of the board. This increases a the current a lot. Nice that they use also low power leds. After some roughly calculations the curren drawn from the pi will be about 3 mA or less. You are safe. You still need to connect ground between the RPI and board. Just connect grount from the RPI (like pin 9 of the 40 pin connector on the pi) to pin 10 of J9 on this board. This way you have a normal closed cercuit to drive those relays.

https://www.sainsmart.com/products/8-channel-5v-relay-module
These board however requires 15-20 mA and need transistors to drive the opto couplers!

For the question of driving from different supply's, I indeed would use at least a seperate one for the pi since relays are nasty for digital electronics. However, if you look at the current, you only might need two. The RPI 3 is recommended about 2.5A. which also validates a seperate supply. now those relays only about .34W whith 8 relays on board, it is 8 X .34 = 2.72W. This means it can draw about 550mA. some other stuff with it means it wil never draw over 1 Amp. So you are safe to put 2, even 3 of those boards with one supply.

Now the reason why it is working with no ground connected. Are you using one supply for the board and the pi together? If so, you connected the ground via the power supply.

 

[Marc Kruithof]

I always pondered about using one of these , but never actually used one. The only thing I’d be verifying is probably if the circuit is 10 amp safe. I believe the perfboard I use can only deal with 4-5amp at max.

This is another area (psu) that I think we need some electronics help @theatrus @Marc Kruithof . Particularly for aio builds as we need 5v (for pi, ato sensors , pca9685 ) 3v (temp, ph ) and 10v (kessil) , 12v (doser). As of now I am using a largest voltage and then for each type a single lm2596 , but that limits 2amp. Also I am fairly sure we are missing some safety circuit across different voltage (diodes and capacitors ) . I am also curious of the effect when all the lm2596 are wired directly to the main dc source vs smaller ones are daisy chained to larger ones (I.e. 12v lm2593 feeds the 5v and so on..)
I have observed pwm flickering while using multiple output from single source using lm2596, which was resolved by increasing pwm clock frequency , but this might just be a ductape

I can help I think, but are you using modules? if so, which? the name lm2596 is the chip used. I want to know the whole circuit. Basicly the whole circuit for powering everything might come in handy. About safety, Everything over 15V without protection is dangerous if no safety precousions are taken. Especialy with water. Then even 5V can be deadly. (it all depends on the current). I can work someting out, but please give me some time to check everything. It will ALWAY be at your own risk.

 

[theatrus]

I will take your expertise on the subject

For the most part will be copying ranjib’s aio build circuitry. Will make sure all is on a common ground .

Suggestion on psu?

https://www.amazon.com/Apevia-ITX-AP300W-Mini-ITX-Solid-Supply/dp/B01M6V8O8T
Would this work?
Housing dimensions are 17x9.06x2.36

Few comments:
- Total overkill in power. The Pi only runs at up to about 5W (lets call it 10W for margins, but it would be overheated in this state since thats a lot of power to move without any heatsinks or other thermal management). Relays may consume 1-2W when held on, each. You should probably downsize to a 5V supply in a "wall wart" or "power brick" form factor.
- Supplies with fans means you're sucking in dust and salt. Prefer passive cooling if possible. Fans fail. Fans are noisy. Really, fans suck.
- I see no safety marks on the supply. This is a rant of mine, but a lot of super cheap supplies on eBay/Amazon/etc haven't met any safety standards (UL/TUV/CSA/ETL). Mains power can deliver very high energy, spend the extra few bucks for something that will fail safely and not in a catastrophic way to property or life. CE is not a safety mark for US markets; also, you can mostly self certify, which means most shops with CE only just attach the label and hope to fly under the EU audit radar.

If you can use 5V relays, I'd source a 5V Meanwell desktop adapter (30-60W range). If you want to do things with 0-10V outputs, use a 12V brick and a power supply module.

 

[Bronc]

Sorry to be such an electronics newb - I am ready to setup the temperature probe but I'm not sure which color wire goes to which connection on the audio jack and the 3.5mm panel mount connector. Those aren't shown on the Build page. Can someone let me know or post a pic of theirs?

 

[Marc Kruithof]

Sorry to be such an electronics newb - I am ready to setup the temperature probe but I'm not sure which color wire goes to which connection on the audio jack and the 3.5mm panel mount connector. Those aren't shown on the Build page. Can someone let me know or post a pic of theirs?

If you bought your sensors online with cable, mostly the red one is +, the yellow is signal, and the black is GND. Look at the picture on the build page. and you will see: +3.3 to the + so pin 1 to the red cable, pin 7 signal so the yellow one. and pin 6 to the GND, so the black one. Also a 4k7 resistor on one end to the red an the other end to yellow.)

 

[Ranjib]

If you bought your sensors online with cable, mostly the red one is +, the yellow is signal, and the black is GND. Look at the picture on the build page. and you will see: +3.3 to the + so pin 1 to the red cable, pin 7 signal so the yellow one. and pin 6 to the GND, so the black one. Also a 4k7 resistor on one end to the red an the other end to yellow.)

Pretty much what @Gareth elliott mentioned.
The way I remember the audio jack pinout (or almost all circular jack, like barrel jacks) is:
If you hold the female connector with its pins towards you , and the input hole away from you, and keep the longest pin above (the other two pins are in both side, with the longest pin in the middle), then
- The one in the right is +ve (for temp sensor, 5v should go here, this is also denoted as vcc or red wire)
- The middle pin, longest one is GND (black or green wire in temp sensor, -ve )
- The left pin is the data pin (white , sometime in other colors in temp sensor).

I 'll share a pic of the connector, soldered in once Im at home (i think one of the page in this thread has it, but its almost impossible to dig it up )

 

[M-A-T-T-Y]

This is amazing, I have 3x Raspberry Pi 3B's and a NUC that I am no longer using (replaced their services with Docker containers) and was looking if there was something I could do with them to help out with the new reef tank I've started.

What a fantastic project, will definitely be giving it a go!

 

[Ranjib]

This is amazing, I have 3x Raspberry Pi 3B's and a NUC that I am no longer using (replaced their services with Docker containers) and was looking if there was something I could do with them to help out with the new reef tank I've started.

What a fantastic project, will definitely be giving it a go!

Thank you for the kind words. Let us know if you need help with your reef-pi build, the guides should help you get started: https://reef-pi.github.io/

 

[Danny Taylor]

this is what I been looking for grrat work
I am a complete noob on coding and electronics but still gunna give it a go
do you ph working yet could not find on site and not read all the forum yet
gunna start with 8 channel relay temp and ato and would like ph

 

[Ranjib]

this is what I been looking for grrat work
I am a complete noob on coding and electronics but still gunna give it a go
do you ph working yet could not find on site and not read all the forum yet
gunna start with 8 channel relay temp and ato and would like ph

Cool.
pH monitoring was introduced recently, documentation is not there yet, it will come soon. I am working on upgrading my builds with ph and doser functionality.
You should not need any programming knowledge. Some familiarity with computer and soldering should be sufficient . Keep us posted on your progress

 

[Bronc]

Got the temperature controller working! (Not actually on the tank yet, but working nonetheless!) Now I need to get started building the wooden cabinet that the reef-pi will be mounted in. It’ll be 60” tall x 14” wide x 20” deep to house all of my tank’s electronics, dosing pump and dosing containers.

 

[Bronc]

Any progress on the new reef-pi user interface? The ui when viewed on the iPad isn’t too friendly. It’ll be even worse when I add the other 8 outlets.

 

[Ranjib]

Got the temperature controller working! (Not actually on the tank yet, but working nonetheless!) Now I need to get started building the wooden cabinet that the reef-pi will be mounted in. It’ll be 60” tall x 14” wide x 20” deep to house all of my tank’s electronics, dosing pump and dosing containers.

Sweet. Keep us posted. I am assuming you got past to the temperature probe connection issues.

 

[Ranjib]

Any progress on the new reef-pi user interface? The ui when viewed on the iPad isn’t too friendly. It’ll be even worse when I add the other 8 outlets.

Yeah, a month at least, I am working on a big change (multiple ato support and multiple temperature probe support) , after that i'll work on customizable dashboard. That will solve this issue. Please let me know anything else (other than the dashboard) that you think needs fixing.
Dashboard customizati0n is kinda must have for multiple ato/temperature probe support, as we just cant simply show all the charts, and user have to select which one he/she wants to be on the dashboard, along side width/heights of individual charts. The width/height customization should fix the iphone issue.

 

[Ranjib]

This is amazing, I have 3x Raspberry Pi 3B's and a NUC that I am no longer using (replaced their services with Docker containers) and was looking if there was something I could do with them to help out with the new reef tank I've started.

What a fantastic project, will definitely be giving it a go!

Keep us posted on how your build goes, we could use every bit of feedback.

 

[Bronc]

Sweet. Keep us posted. I am assuming you got past to the temperature probe connection issues.

I did. Your description of the connector was perfect. (But wow, those wires in the temp probe are SMALL for 50 yr old eyes!)

I can’t thank you enough for doing this for us Ranjib! This reef-pi project is amazing!

 

[Ranjib]

I did. Your description of the connector was perfect. (But wow, those wires in the temp probe are SMALL for 50 yr old eyes!)

I can’t thank you enough for doing this for us Ranjib! This reef-pi project is amazing!

These kind words keep this project going, really appreciate it.

 

[Gareth elliott]

With the customization of sizes will we be able to have option to save presets?

If i resize for the pi screen but also use my phone or my mac monitor at times.

Not tremendously important but an idea before it’s implemented and harder to add display functions.

 

[Ranjib]

With the customization of sizes will we be able to have option to save presets?

If i resize for the pi screen but also use my phone or my mac monitor at times.

Not tremendously important but an idea before it’s implemented and harder to add display functions.

Yes. My initial idea is to allow the grid (currently 2x3) of charts and individual chart size (currently fixed at 500px X 300px ) to be customizable by users, and it will persist,

 

[Ranjib]

I did. Your description of the connector was perfect. (But wow, those wires in the temp probe are SMALL for 50 yr old eyes!)

I can’t thank you enough for doing this for us Ranjib! This reef-pi project is amazing!

I know :-(. Good thing is I have a tiny helper (kidding)