reef-pi new daugther board

Roberto_b · Oct 16, 2018

I'm looking for new project open source for reef-pi, a daugther board plugin on Pi3 (same size), i like collect the most request interested for users.
Make your suggestion in this thread, i like discuss about this.

My idea start from these specs :
- screw clamps for temperature probes (2)
- screw clamps for input level switch (4)
- Lipo & circuit management for Pi3 UPS, in order to run when power supply fail
- socket PCIe for LTE/4G modem, for connectivity when power supply fail, in order to have instan alarm.
- screw clamps for PWM/Analog output, useful for variable speed pumps & dimming lights, 5V pwm, 0/5V analog, 0/10V analog, selectable for each channel, 8 channel.

what's more ?

Reefing Madness · Oct 17, 2018

Ranjib · Nov 14, 2018

For anyone who might be intersted, @Roberto_b already published an openhardware design for pH board, here: https://www.reef2reef.com/threads/reef-pi-ph-orp-adapter.478158/
I am in process of adding the software support for this board in reef-pi. I am very excited about this, as I hope this can bring down the cost of pH monitor builds, currently we use atlas scientific ezo circuit, which cost a fortune and is patented :-/ , so no way to improve things from our learning

wykat · Nov 16, 2018

Roberto_b said:
I'm looking for new project open source for reef-pi, a daugther board plugin on Pi3 (same size), i like collect the most request interested for users.
Make your suggestion in this thread, i like discuss about this.

My idea start from these specs :
- screw clamps for temperature probes (2)
- screw clamps for input level switch (4)
- Lipo & circuit management for Pi3 UPS, in order to run when power supply fail
- socket PCIe for LTE/4G modem, for connectivity when power supply fail, in order to have instan alarm.
- screw clamps for PWM/Analog output, useful for variable speed pumps & dimming lights, 5V pwm, 0/5V analog, 0/10V analog, selectable for each channel, 8 channel.

what's more ?

You're just around 5 hours drive from where I live (Klagenfurt Land), almost "neighbors"

. Your approach is very similar to mine with following remarks/comments:
- Screw clamps or connectors, yes the connectors are key but I think also related to the final housing connectors. Making a PI daughterboard makes it very compact, especially for the connectors. I'm still puzzling with this myself. I have some preliminary ideas about housing and connectors, especially with respect to maintenance.
- Lipo and UPS is also in my mind. My approach is to make a separate PI size "base plate" with 5V and 12V UPS supported power supply to the PI and daughter boards. My Reef-PI_HAT v2 should allow input for 12V and 5V and be able to power the PI itself as Ranjib proposed. First want to verify my PWM module however.
- LTE/4G modem is new to me but I think a good approach

What I'm still puzzling around is a 'watchdog' function, preferable via external hardware (PI zero/Arduino), to verify that Reef-PI is still running, so not just if it receives power, with the watchdog hardware either powered by the PI UPS or a separate one. Either a relay or PWM signal could be used to trigger Reef-PI is still 'alive' and 'kicking'.

Ranjib · Nov 16, 2018

wykat said:
You're just around 5 hours drive from where I live (Klagenfurt Land), almost "neighbors". Your approach is very similar to mine with following remarks/comments:
- Screw clamps or connectors, yes the connectors are key but I think also related to the final housing connectors. Making a PI daughterboard makes it very compact, especially for the connectors. I'm still puzzling with this myself. I have some preliminary ideas about housing and connectors, especially with respect to maintenance.
- Lipo and UPS is also in my mind. My approach is to make a separate PI size "base plate" with 5V and 12V UPS supported power supply to the PI and daughter boards. My Reef-PI_HAT v2 should allow input for 12V and 5V and be able to power the PI itself as Ranjib proposed. First want to verify my PWM module however.
- LTE/4G modem is new to me but I think a good approach

What I'm still puzzling around is a 'watchdog' function, preferable via external hardware (PI zero/Arduino), to verify that Reef-PI is still running, so not just if it receives power, with the watchdog hardware either powered by the PI UPS or a separate one. Either a relay or PWM signal could be used to trigger Reef-PI is still 'alive' and 'kicking'.

Raspberry Pi itself has a hardware watchdog, and the init system in linux/raspbian (systemd) can be configured to supervise that and restart Pi or individual services if need be. Albeit this is not as fullproof as external watchdog, but its at least hardware backed

wykat · Nov 16, 2018

Ranjib said:
Raspberry Pi itself has a hardware watchdog, and the init system in linux/raspbian (systemd) can be configured to supervise that and restart Pi or individual services if need be. Albeit this is not as fullproof as external watchdog, but its at least hardware backed

Yes, but as discussed in the main Reef-PI thread, the main problem is the SD-card itself, then Raspberry may restart under power but Reef-PI will never come up again. I think with the investments made to a Reef, such a low cost investment for an external watchdog would give me a more comfortable feeling, either sending messages via LAN (my house has a LAN/Firewall/Router protected PSU), WLAN of LTE/4G modem.

Ranjib · Nov 16, 2018

wykat said:
Yes, but as discussed in the main Reef-PI thread, the main problem is the SD-card itself, then Raspberry may restart under power but Reef-PI will never come up again. I think with the investments made to a Reef, such a low cost investment for an external watchdog would give me a more comfortable feeling, either sending messages via LAN (my house has a LAN/Firewall/Router protected PSU), WLAN of LTE/4G modem.

So, if SD card is fried, how an external watchdog will help, the message delivery will be entirely based on firmware in the LTE module? I find it easier to just send some health data to external site (say adafruit.io) and alert when thats missing (from external site)

wykat · Nov 16, 2018

Ranjib said:
So, if SD card is fried, how an external watchdog will help, the message delivery will be entirely based on firmware in the LTE module? I find it easier to just send some health data to external site (say adafruit.io) and alert when thats missing (from external site)

Don't know how Roberto_b wants to implement his idea but my view would be that the UPS/Watchdog would manage the LTE module independently from the PI. It doesn't make sense to have the PI manage the LTE module when no power source is available. I understand your approach using an external site, haven't looked into that yet.

Roberto_b · Nov 26, 2018

wykat said:
Don't know how Roberto_b wants to implement his idea but my view would be that the UPS/Watchdog would manage the LTE module independently from the PI. It doesn't make sense to have the PI manage the LTE module when no power source is available. I understand your approach using an external site, haven't looked into that yet.

Hello,
sorry fo the delay in this post, honestly i'm poor in time to manage all thing i like...

, the project is finished as design for schematic & pcb, i like share it as Ranjib provide respository , i understand the tema, i was thinking about watchdog, but i know is already available in processor of pi3, so probaly is just necessary enable it on reef-pi if today is not managed, at first occasion i will ask to Ranjiib. To manage GSM alarm if pi3 doesn't boot up is not easy, means provide microcontroller on carrier and manage gsm, a lot of work to do....., i know very well the tema of uSD card, there are some consideration when you use them, is well done there is no reason to have a fail on sd card. In my old system computer the GSM is sending a message when power is down, and continue to send an alarm each 3 min when power is down and a message when power rise up, so you have under control the situation without too much complex system.
A case where SD is damaged and the system failt to boot is very rare, teorically one time you have started the system it does't switch off anymore, not without a human operation, when you use SD is important use large SD respect the required size, so file system can manage and increase reliability, more then is important use uSD class 10, better if industrial SLC instead consumer MLC. They change drammatically the reliability, with right SD card you will have not problem on file system.

Roberto_b · Nov 28, 2018

just started pubblic repo

https://github.com/robertobuti/reef-pi_Pi3-daughter-board

speedstar · Nov 29, 2018

Roberto_b said:
A case where SD is damaged and the system failt to boot is very rare, teorically one time you have started the system it does't switch off anymore, not without a human operation, when you use SD is important use large SD respect the required size, so file system can manage and increase reliability, more then is important use uSD class 10, better if industrial SLC instead consumer MLC. They change drammatically the reliability, with right SD card you will have not problem on file system.

I need to upgrade my SD as it has happen to me twice. Both from power outage

rushbattle · Nov 29, 2018

Anyone have a SLC SD card picked out?

theatrus · Nov 29, 2018

rushbattle said:
Anyone have a SLC SD card picked out?

An option, but not going to win any awards:
https://www.mouser.com/ProductDetail/Panasonic/RP-SMSC01DA1

(ironically this is the price I just paid for a 400GB uSD card)

rushbattle · Nov 29, 2018

theatrus said:
An option, but not going to win any awards:
https://www.mouser.com/ProductDetail/Panasonic/RP-SMSC01DA1

(ironically this is the price I just paid for a 400GB uSD card)

Yeah, it looks SLC isn’t going to happen. An 8gb card is over the total budget for a typical reef-pi build with the dj strip.

theatrus · Nov 29, 2018

rushbattle said:
Yeah, it looks SLC isn’t going to happen. An 8gb card is over the total budget for a typical reef-pi build with the dj strip.

There are MLC cards rated for industrial temperature ranges, but I'm unsure this is anything but a higher bin normal SD card.

I'd just focus on using high quality cards and not worry too much.

crusso1993 · Nov 29, 2018

rushbattle said:
Yeah, it looks SLC isn’t going to happen. An 8gb card is over the total budget for a typical reef-pi build with the dj strip.

There are also LiteSLC cards that aren't too crazy on price point.

Ranjib · Feb 17, 2019

@Roberto_b any update on this?

Roberto_b · Feb 20, 2019

Hello Ranjib,
yes sorry if i disappear for some time, i have had hard family problem, but now i'm back on normal activity.
I have the PCB and all components for assemble the prototype, i will provide shortly so after quick hw test the project will shared and any one can use it, obviously i will need your help to implement some controls / functions.

bye

Ranjib · Feb 20, 2019

Roberto_b said:
Hello Ranjib,
yes sorry if i disappear for some time, i have had hard family problem, but now i'm back on normal activity.
I have the PCB and all components for assemble the prototype, i will provide shortly so after quick hw test the project will shared and any one can use it, obviously i will need your help to implement some controls / functions.

bye

Sorry to hear family trouble, I hope things are better now. Family comes first, always. Happy to help anyway I can on the daughter board integration.