EcoRenovator  

Go Back   EcoRenovator > Improvements > Geothermal & Heat Pumps
Advanced Search
 


Blog Register 60+ Home Energy Saving Tips Recent Posts Search Today's Posts Mark Forums Read


Reply
 
Thread Tools Display Modes
Old 07-13-14, 11:33 PM   #111
NiHaoMike
Supreme EcoRenovator
 
NiHaoMike's Avatar
 
Join Date: Oct 2008
Location: Austin, TX
Posts: 1,142
Thanks: 14
Thanked 252 Times in 237 Posts
Default

My favorites are the various PICs. Anything from tiny 6 pin low cost microcontrollers to huge 100+ pin 32 bit processors are supported by MPLAB X, including many breadboard-friendly DIP devices. The dsPICs are especially good for motor control.

It's obvious that Arduino has evolved significantly from its humble 8 bit beginning now that they have some ARM based boards. But the diversity of supported devices is nowhere as much as MPLAB X. 8 bit is enough to do a lot if you know the tricks of how to do good programming on them. Nowadays, a low end ARM or dsPIC doesn't cost much and can be a real time saver as it lets you get away with higher level programming, such as using a RTOS.

Main problem with Arduino classic (Uno and related) is that the memory isn't enough to really run a RTOS. That significantly complicates things when the application has to periodically check and adjust parameters and still respond quickly to user interaction.
FreeRTOS on Arduino | maniacbug
Quote:
FreeRTOS on Arduino Uno?

FreeRTOS works great on 1284P and Maple. After some heavy experimentation, I was able to get the pingpair sketch working on an Arduino Uno clone. It turns out that a heap of 1300 and per-task stacks of 150 did the job. In total, 380 bytes of SRAM remain free when the sketch is loaded.

The question is whether this is a good idea. This is just a simple ‘hello world’ for radios, 380 bytes doesn’t leave much for more complex application logic or more tasks.

__________________
To my surprise, shortly after Naomi Wu gave me a bit of fame for making good use of solar power, Allie Moore got really jealous of her...
NiHaoMike is offline   Reply With Quote
The Following User Says Thank You to NiHaoMike For This Useful Post:
MN Renovator (07-14-14)
Old 07-14-14, 09:05 AM   #112
AC_Hacker
Supreme EcoRenovator
 
AC_Hacker's Avatar
 
Join Date: Mar 2009
Location: Portland, OR
Posts: 4,001
Thanks: 303
Thanked 712 Times in 532 Posts
Default

Quote:
Originally Posted by NiHaoMike View Post
My favorites are the various PICs...
NiHaoMike,

Writing a poem in very few words that precisely expresses a situation is far more difficult that writing a descriptive essay about the same thing. In the same way, designing a minimalist, elegant solution is more difficult than using a more powerful and complex set of tools.

The idea of this thread is to design a heat pump controller that can leverage the minimum of the simplest and most commonly available parts, and that will appeal to the widest possible audience of non-advanced people, who at this time are using the extremely popular Arduino IDE.

It is not clear to me if you are trying to be helpful in this discussion of designing a very basic general purpose heat pump controller or if you are trying to confuse and divert the conversation.

If your intention is helpful and genuine, and you simply can't resist the urge to offer ideas that are outside the scope of this effort, you will welcome the opportunity to carry your ideas and insights to a more appropriate thread that I started called "Designing an Advanced Heat Pump Controller".

Best of luck.

Sincerely,

-AC_Hacker
__________________
I'm not an HVAC technician. In fact, I'm barely even a hacker...

Last edited by AC_Hacker; 07-14-14 at 09:09 AM..
AC_Hacker is offline   Reply With Quote
The Following User Says Thank You to AC_Hacker For This Useful Post:
ICanHas (08-10-14)
Old 07-14-14, 07:03 PM   #113
NiHaoMike
Supreme EcoRenovator
 
NiHaoMike's Avatar
 
Join Date: Oct 2008
Location: Austin, TX
Posts: 1,142
Thanks: 14
Thanked 252 Times in 237 Posts
Default

It can be done with a bunch of trickery. As in use a timer interrupt to run the control routine and make sure all the buttons can trigger interrupts so the UI can respond almost instantly.

The real question is why when there are cheaper processors that are far more capable?
__________________
To my surprise, shortly after Naomi Wu gave me a bit of fame for making good use of solar power, Allie Moore got really jealous of her...
NiHaoMike is offline   Reply With Quote
Old 07-14-14, 07:43 PM   #114
AC_Hacker
Supreme EcoRenovator
 
AC_Hacker's Avatar
 
Join Date: Mar 2009
Location: Portland, OR
Posts: 4,001
Thanks: 303
Thanked 712 Times in 532 Posts
Default

Quote:
Originally Posted by NiHaoMike View Post
The real question is why when there are cheaper processors that are far more capable?
I think the part you apparently don't understand is that we are not only designing a device to control a heat pump, we are also designing a device that uses the most popular and widely available hardware and IDE. That would be the Arduino IDE by a long shot. In other words, we are designing to the enormous pool of Arduino users.

In 2013, 700,000 official Arduino boards were in users' hands... That count doesn't even include the uncountable number of clone boards that are being used.

EDIT: Here are some numbers I just now ran...
Code:
		Google		YouTube
Arduino		41600000	1050000
PIC		2090000		47300
RTOS		4710000		8520
MPLAB X		552000		6790
FreeRTOS	526000		4280

When you look at it as a graph:


The blue bars are Google hits, a sign of curiosity, if not real interest.

The red bars are YouTube hits, which are user-created, are a more accurate indicator of users being actively involved.

I think you, being well educated and technically sophisticated, are only looking at optimum hardware and software solutions and not at the huge established Arduino user population that is internationally established, and may not have access to hardware or any experience at all with any of the hardware and software combinations that you insist on suggesting.

If you are interested in this particular effort, please lend a hand. If you are not interested in helping with this particular effort, you do have a thread, Designing an Advanced Heat Pump Controller where you can prove your point by creating a superior design.

In other words, put your talent where your talk is.

-AC
Attached Thumbnails
Click image for larger version

Name:	Arduino vs others.jpg
Views:	787
Size:	23.4 KB
ID:	4492  
__________________
I'm not an HVAC technician. In fact, I'm barely even a hacker...

Last edited by AC_Hacker; 07-15-14 at 11:12 AM..
AC_Hacker is offline   Reply With Quote
Old 07-14-14, 08:13 PM   #115
NiHaoMike
Supreme EcoRenovator
 
NiHaoMike's Avatar
 
Join Date: Oct 2008
Location: Austin, TX
Posts: 1,142
Thanks: 14
Thanked 252 Times in 237 Posts
Default

The classic Arduino only has one UART. That's enough for a very basic controller, but it seems like you wanted two independent RS485 ports. You'll want a Mega or Due for that. Actually, you'll want more GPIOs than the classic Arduino provides if you want to avoid using port expanders, which can be confusing for a beginner.
__________________
To my surprise, shortly after Naomi Wu gave me a bit of fame for making good use of solar power, Allie Moore got really jealous of her...
NiHaoMike is offline   Reply With Quote
Old 07-15-14, 12:00 PM   #116
AC_Hacker
Supreme EcoRenovator
 
AC_Hacker's Avatar
 
Join Date: Mar 2009
Location: Portland, OR
Posts: 4,001
Thanks: 303
Thanked 712 Times in 532 Posts
Default Custom Arduino PCBs...

jeff5may & all,

I went down to my local Geek hang out last night (DorkBotPDX.org) and chatted with a few folks. One of them, to whom I gave a URL of our discussion, has shown an interest in what we are doing, and is interested in offering PCB design support for our project. Of great interest to me is that he has already done PCBs for Arduino shields, which opens up some very interesting possibilities.

So we're not necessarily locked in to existing shields.

The up-side is that it expands our design possibilities, and the down-side is that it reduces the off-the-shelf appeal of our project.

* * *

Please understand, I don't want to seem negative here, but rather speak as a 'Devil's Advocate', and ask questions regarding possible 'project creep'...

In considering NiHaoMike's comment about including two independent RS485 ports... Do we actually require these on our most basic controller? Are two RS485 vital to functioning? How will they be used? Can someone explain to me why one RS-232 would not be sufficient?

How vital is the LCD display? Does it's utility truly justify the resources required to run it? I don't question that enough clock cycles will be available, but how about I/O resources and memory consumed? Could we not get by with a few indicator lights and maybe an alarm beeper? Can we not connect yo the USB to change specific vartiables?

By the way, I previously used a data-logger from Spark-Fun called Log-O-Matic, I don't know if it is still sold, but one feature about it that was very interesting is that on start-up, it would read an ASCII file that was available in memory, and that file had specific variable values that the logger would read at start-up. It made it very easy for a new user to tweak those values, values like time between data-read cycles, etc. BTW, if that data file was missing or corrupt, it would create the original default file.

If we have sufficient resources to accomplish our aims, an LCD display is just great. I'm just thinking about complexity here...

Best,

-AC
__________________
I'm not an HVAC technician. In fact, I'm barely even a hacker...

Last edited by AC_Hacker; 07-15-14 at 03:07 PM..
AC_Hacker is offline   Reply With Quote
Old 07-15-14, 01:01 PM   #117
stef110
Helper EcoRenovator
 
Join Date: May 2014
Location: Holland
Posts: 58
Thanks: 6
Thanked 3 Times in 3 Posts
Default

The pcb design is not a real big deal. I draw my circuits in eagle 6.6 the free trial version is available on there website.
But i though you don't want that, because people would have to solder there own circuit board.

The discussion about the two rs485 lines I believe that is my fault. I want those lines because that i need my controller to communicate with other heating controllers on my place. I placed the two lines on the arduino using the software serial library by this way you can make extra serial lines.

An lcd display is very handy to simply look what kind of temperatures your running without the use of computer. If you want to create a controller that will be handy for everybody you should really keep the display on the project.

stef
stef110 is offline   Reply With Quote
Old 07-15-14, 01:56 PM   #118
takyka
Helper EcoRenovator
 
Join Date: Jul 2014
Location: Hungary
Posts: 34
Thanks: 0
Thanked 16 Times in 10 Posts
Default

How important is to have LCD is up to the user's taste. If you have computeror tablet at hand, It's more convenient to get/set datas with it. In my system there is the possibility to connect LCD, but I did not spend time to write code and make it work. The reason, I found way more convenient to do configuration from computer or tablet via simple menu, rather than on a tiny screen, pressing small buttons up&down. In this respect even a 4x20 character LCD is too small to display enough data. To use the five button to adjust parameters is a pain, comparing to type data on keyboard. My menu system could be easily implemented to your project too including parameter storing, 1W device assignment. It would fit to UNO easily.

T.
takyka is offline   Reply With Quote
Old 07-15-14, 02:47 PM   #119
AC_Hacker
Supreme EcoRenovator
 
AC_Hacker's Avatar
 
Join Date: Mar 2009
Location: Portland, OR
Posts: 4,001
Thanks: 303
Thanked 712 Times in 532 Posts
Default

Quote:
Originally Posted by takyka View Post
How important is to have LCD is up to the user's taste. If you have computeror tablet at hand, It's more convenient to get/set datas with it. In my system there is the possibility to connect LCD, but I did not spend time to write code and make it work. The reason, I found way more convenient to do configuration from computer or tablet via simple menu, rather than on a tiny screen, pressing small buttons up&down. In this respect even a 4x20 character LCD is too small to display enough data. To use the five button to adjust parameters is a pain, comparing to type data on keyboard. My menu system could be easily implemented to your project too including parameter storing, 1W device assignment. It would fit to UNO easily.

T.
Sounds interesting... More details please...

-AC
__________________
I'm not an HVAC technician. In fact, I'm barely even a hacker...
AC_Hacker is offline   Reply With Quote
Old 07-15-14, 03:32 PM   #120
AC_Hacker
Supreme EcoRenovator
 
AC_Hacker's Avatar
 
Join Date: Mar 2009
Location: Portland, OR
Posts: 4,001
Thanks: 303
Thanked 712 Times in 532 Posts
Default

Quote:
Originally Posted by Ormston View Post
Also a mechanical thermostat could be mounted on the condenser input line and evaporator water outlet and wired inline with the compressor relay coil to shutdown the compressor in the event of over temp/pressure or freezing ground loop water.

Safety circuits should never rely on software.
I went back to find this post, because it had mostly passed without comment.

I think Steve is absolutely right in saying that "Safety circuits should never rely on software".

I completely agree because every computer device, no matter how small, even the humble 4-function calculator, has a tiny paperclip sized hole for performing a reset, in case their little brain locks up. In the case of a calculator, it's no big deal, but if you're away from home and something in you heat pump system goes crazy (maybe even because of a locked-up cpu), you'll want the security of a non-software provision to prevent damage to the system. I mean I got lucky when I got the brazed plate HX of my dreams for about $90, but if it was in mid-winter, and I needed a replacement for that same HX, it could easily cost me $700... saying nothing about down-time and re-installation hassles, etc.

Best,

-AC

__________________
I'm not an HVAC technician. In fact, I'm barely even a hacker...
AC_Hacker is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 04:09 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2022, vBulletin Solutions Inc.
Ad Management by RedTyger
Inactive Reminders By Icora Web Design