Which ARM Board for remote control?

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Which ARM Board for remote control?

Postby linux4michelleWeb » 2019-07-15 15:54

Good evening,

since quiet a while I am more or less off-line because I have since 3 years an Organic Farm in Estonia near Rakvere which occupy my heavily,
but I am 100% Off-the-Grid (powerd trough solar- and windenergy based on 24V DC) and it is time to get back to Open Source.

I need for my 5 Windmills, 3 Solarpanel sets and consumption measuring systems and remote control for field watering.

So what is up-to date?

The WHOLE system must be OF COURSE Open Source and Debian!

My questions are now (especially on people which already do it):

1) Which microcontroller board to use for remote controlling of 4 electromagnetic valves and two buttons?
Must have WiFi which has to work over a distance of up to 200m (free range) while my next neigbour is more then 600m distance.
Should get an independant web interface

2) Need something more powerful as a Victron Energy Color Control GX.
Banana PI M1?

Thanks in advance and nice evening
from Estonia
Michelle
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Re: Which ARM Board for remote control?

Postby arzgi » 2019-07-16 11:56

linux4michelleWeb wrote:Good evening,

1) Which microcontroller board to use for remote controlling of 4 electromagnetic valves and two buttons?
Must have WiFi which has to work over a distance of up to 200m (free range) while my next neigbour is more then 600m distance.
Should get an independant web interface



Interesting project! To microcontrollers, I would say any, at least with some add-on board. I have only Raspberries, pymcus https://www.tindie.com/products/richardw/pymcu/, which are not made any more, but there are others. Also I have http://jap.hu/electronic/relay_module.html, to quite general usage.

About wifi range, I have used only inside, but I think your favorite search engine would help. And there are wifi extenders too.

I have a faint memory, it might have been some MagPi (Pi Magazine), where one person had made a weather station in a remote tropic island.
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Re: Which ARM Board for remote control?

Postby pylkko » 2019-07-16 19:02

Well if the question is which processor/architecture to use over wifi to control valves and sensors, then I think one candidate is WiPy from Pycom, since 1) they claim wifi range of 1 km 2) the board is designed so to allow the ESP32 cores to actually utilize low power modes (unlike most other boards with Xtensa architecture processors, where peripherals prevent achieving the lower states). And the dual core Xtensa 240 Mhz probably can handle anything you need. You can even run an operating system on it (like FreeRTOS).

The most standard way to do this with linux, is to run a linux server node, and then have the devices communicate over MQTT because it consumes many times less energy and is many times faster than http. A open source MQTT broker software is called mosquito (you can just apt install mosquito on Debian). It is extremely simple and straight forward to set up. Boards with processors capable of MQTT over wifi cost anywhere from 1 to 5 USD a piece from China

However, since you are off the grid, you probably want to consume as little power as possible (to extend battery life). You also need large distances, but it looks to me you do not need high throughput (like video streams). In such a situation it will most likely make sense to not use wifi. The linux kernel supports other low energy communication methods like LoRa, which can get you ranges up to hundreds of km and use significantly less energy. Anything with wifi is not going to last many days on any batteries of any kind.
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Re: Which ARM Board for remote control?

Postby linux4michelleWeb » 2019-07-17 10:51

Thank you for your replies.

I will have a look into it.

I have no clue about MQTT and do not know, how to access the data from PHP.

I was thinking to run a Banana PI Zero (bought already), but it seems, it has a very poor WiFi support.
Same for Orange PI Zero.

My Batteries have 70kWh (24V 2940Ah) and will be doubled because of the Greenhouse and Earthstorrage.
The 5 Windmills (7400W total) and the 2400Wp Solarpanels deliver more energy as I actually need.
Hence, energy is not the problem.

However, the WindMAX2500 MPPT Chargers are connected over the USR-TCP232-T2 module (I have 15pcs of it) to an industrial Ethernet Switch and from there I go with FiberOptic OM2 cables to my Server...

Only my Victron Energy BlueSolar MPPT 150/85 need an CAN-Ethernet Media Converter which I do not have currently.

So, I like to install a Banana PI M1 (got it 3 weeks ago for trying out, it has a CAN port Raspberry not) in my PowerStation and collect the Data and show real-time data mainly for maintenance and demonstration to visitors.

In the house I have a 15,4" Monitor 1920x1280 with a second Raspberry/Banana/Orange PI (currently I do not know which one to buy) which show the whole farm including Watering System, Compost Heating and much more.

However, I still need a reliable WiFi AP. The Outdoor ones are too expensive from what I have seen, so I can even install the WiFi AP on my future Greenhose (I have a FiberOptic cable there) to increase the Signal and reduce the Distance to the Remote Controller.

Any suggestions for an EU compatible AP?
I have an US Version which give me definitive trouble here with the Militaries and Border Police in Estonia if I switch a 25W AP on.

Have a nice day
Michelle
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Re: Which ARM Board for remote control?

Postby pylkko » 2019-07-17 19:22

There seems to be some confusion in this discussion. You are talking about microcontrollers, but it appears that you are referring to computers capable of running linux like Banana Pi with this term, which is not the normal usage. Also, when I stated that off-grid you may want to use low energy nodes, I didn't mean that it is not possible to generate enough power, but rather that often people want these nodes in places where they do not want to draw power cables to, especially since if you do that, you might as well draw ethernet at the same time. You cannot put a car battery at every single device you have in the field, can you? Microcontrollers like ESP32 can run off a few AA-batteries for months switching on and off an irrigation valve, so they can have their own small solar panel and run off that independently forever, working only a simple script written in C, no operating system or other things to add additional complexity where things can go wrong.

But now you seem to be asking about acquiring a WiFi access point. I don't have any knowledge on this topic. But I suspect you could make your own directional high power antennas (it's as simple as rapping a wire around a Styrofoam piece, look it up). This make brake regulations (depending on what you do) but if you use directional antennas and there are no neighbors even, there is little likelihood it would actually bother someone.
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Re: Which ARM Board for remote control?

Postby linux4michelleWeb » 2019-07-18 13:06

For the "a little bit bigger" Microcontroller, I like to do in the future more then only switching 2 valves and have two buttons on it.
I like also to measure the voltage drop on the 24V DC power line and whatelese.

Since the electro magnetic water valves are 24V DC, and all of my PowerTools have 24V DC, the 24V are availlable on the whole (experimental) farm which is a longer history (ex "Mobile Eco City").

Also you forgot, that Ethernet has a range limit of 100m which I would exceed (longest possibel distance would be then arround 300m)
I want to place already the WiFi AP in a more central place and this is why I need a WiFi which work in open terrain of 100m (maybe a little bit more)
Ethernet can not be used, because a direct lighting hit would kill anything.

This is why my intranet server has it own "UPS" and the charger is physically disconected while we have a thunder here.
All other locations (Farmhouse, PowerStation, Greenhouse, EarthStorrage, Wifi AP, ...) are connected trough MultiMode FiberOptic Cables.

For the antenna, it has to be a Point-to-Multipoint.

It seems, I will install a seperated (6-8m) mast for it, because someone has suggested me (an inexpensive) one, but this could result in a range of more then 500m and I have to reduce the power a little bit.

The question now is: Is there a better Microcontroller as the Banana/Orange PI Zero with WiFi?

Greetings
Michelle
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Re: Which ARM Board for remote control?

Postby pylkko » 2019-07-18 15:06

For the "a little bit bigger" Microcontroller, I like to do in the future more then only switching 2 valves and have two buttons on it.
I like also to measure the voltage drop on the 24V DC power line and whatelese.


A baremetal c-binary running microcontroller can easily do all this. You don't need a Banana Pi or other single-board computer. It's way overkill. However, if that is what you like or are used to, then you should go with that.


I kind of didn't understand yet if the machines that you want to control will be in buildings with fiber optics or not? Why do you need the WiFi?

However, as far as I know, most of the single board computers have similar wifi modules with the antenna being a trace on the board. I doubt that there will be much difference between them (although there will be small variances).You can, however, find ones which have connectors for (uFL) external antennas, which then significantly improves their performance and range. Or you can use WiFi extenders/repeaters if you don't want to have a mast.

for example, a single-board computer with an external antenna plug:
https://somlabs.com/wp-content/uploads/ ... f-v1-1.pdf

that can even run Debian

All of this should be doable with WiFi, if you have line-of-site and the power needed for the devices.
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Re: Which ARM Board for remote control?

Postby linux4michelleWeb » 2019-07-24 08:47

I need WiFI

Cabeling 20 microcontrolers with FiberOptic cable would be too expensive, even if I have a bunch of NEW TP-Link media inverter for free.

If I place an 8m high mast for the WiFi AP more or less centered on the Farm and cabel with a FiberOptic cable, the longest WiFi distance then would be approximately 150m without anything in between (free sight).

Hmm, I was not thinking on WiFi extenders/repeaters... :shock:

If they are small enough, I can install them inside my Power/Water Supply Boxes where I have anyway 24V DC available.
Then the longest distance would be only 70m but require at least 5 repeaters which have free sight to each neihgbour repeater.

From the house to the first WiFi repeater it is also 60m without anything in between.

Any suggestions for a microcontroler with 4I, 4O and 1/2AI?

I have only Experience with NXP LPC11C24 Cortex M0 CAN Controller and PIC32 and some 80xx controller.

Any programming must be done/possibel (of course) under Debian 9...
...otherwise it will make no sense!

Have a nice day
Michelle
Sweating on the farm by 31°C...
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Re: Which ARM Board for remote control?

Postby pylkko » 2019-07-26 17:40

Personally I would still use a lpwan network not wifi

https://en.m.wikipedia.org/wiki/LPWAN

As it can go through objects and the you won't need line of sight. Plus the other previously mentioned benefits.

However, if the distance is only 70 m max, it might be doable with wifi. A router that works as a repeater is in essence a Linux sever and can do probably whatever you need it to do. In other words, they could replace the entire microcontroller. What microcontrollers to use depends on what the work load is that they will be running.
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Re: Which ARM Board for remote control?

Postby linux4michelleWeb » 2019-10-29 05:45

After some testing, LPWAN will be definitively not used!

1) The range is not more then 30m

2) It can be easily manipulated from malicious peoples.

I have just cracked my own test installation and screwd up my field watering system.
Also it is much easier to jam LPWAN.

Have a nice day
Michelle
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Re: Which ARM Board for remote control?

Postby pylkko » 2019-10-29 09:03

I am not sure what you mean. LPWAN is a umbrella term used to refer to multiple distinct protocols for transferring data over large distances on low power. The record for sending data on LoRa is 702 km (from Wrocław, Poland to Osterwald, Germany). To be fair the people doing this used high altitude balloons, but, nevertheless, it is pretty standard to get ranges of around 10 km with antennas on ground, and under 2 km should be possible pretty much out of the box. There are multiple videos on youtube where people communicate with drones, heck, I even saw one where a guy was using a cheapo chinese no-brand device to connect his car to his home network (driving around the city and stuff).

I am not certain that all the protocols use encryption, however. I believe that LoRA does not use, unless you incorporate it. But LoRaWAN networks use AES, which means it should be doable. There are also many public routers and it might be possible to create a network using these (https://www.thethingsnetwork.org/)

However, there are some 802.11 (wifi) protocols that allow larger than normal range (802.11n has as mode that cites 1 km), and it might be an option also. The downside is that these usually work only "in theory" on long range, and need to have "line of sight". So there cannot be anything in the way, like trees or walls or the range will drop. Also, in practice you cannot run these devices on battery, they just consume so much energy.

If you want to do it fairly cheaply (no special protocol devices) and you have unlimited power in the field, then I guess you could just try using more powerful and larger antennas with standard home wireless routers. Each country has it's own regulations on how far you can take this, so you have to be careful (unless you are in such a remote area that you are unlikely to bother other people and are willing to take the ethical/legal risk).
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Re: Which ARM Board for remote control?

Postby worksAsIntended » 2019-11-13 11:12

I would suggest going really easy with wifi extension and a couple of esp32 boards.
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Re: Which ARM Board for remote control?

Postby pylkko » 2019-11-17 12:14

With a board made from a ESP32 (on board antenna) you will probably get like 10 m range max...

https://www.esp32.com/viewtopic.php?t=4124
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