MJLorton Solar Power and Electronic Measurement Equipment Forum

New proof of concept ideas, projects, inventions => New proof of concept ideas, projects, inventions => Topic started by: Mr Eastwood on August 13, 2012, 05:31:02 PM

Title: Temperature Controller
Post by: Mr Eastwood on August 13, 2012, 05:31:02 PM
This is something I've been working on for the last 2 years in my spare time.  It's a ramp/hold temperature controller,  it controls temperatures up to 1300'c based on temperature profiles which are created in XML then sent to the controller via rs232, the unit has a internal logging facility to store each successful run operation; then you can pull the logs from memory to the PC to be displayed as a graph. It has a COM mode that allows you to send commands from the PC to it. This pic doesn't show the rs232 module board.

It's taken a long time to create as it's my first real project and everything I've learned I've had to pick up on the way.  I've really got hooked on electronics now and I'm keen to get this finished so I can get started on the next version.

(http://3.bp.blogspot.com/-hSiBP9XYvcQ/T_lVJQrjraI/AAAAAAAABM0/0vhXD-sGQQU/s1600/kiln_controller_proto_type_2.JPG)

Title: Re: Temperature Controller
Post by: MJLorton on August 15, 2012, 06:05:52 AM
Brilliant, hats off to you and thanks for posting.

Cheers,
Martin.
Title: Re: Temperature Controller
Post by: Mr Eastwood on May 29, 2013, 07:51:07 AM
Just a small update; after doing the top board I wanted something to fit into a project box, so I created a smaller 2 board version.

(http://3.bp.blogspot.com/-HTdk3zZC9XI/UR17gzjd1hI/AAAAAAAABWw/G-pROe6AM_A/s640/DSC02484_small.jpg)

(http://1.bp.blogspot.com/-4mtGAKecFmY/USteSQN58CI/AAAAAAAABXE/Ymjdt23E2Qw/s640/DSC02493_small.jpg)

Here's a small time-lapse clip build showing the part construction of the main board.
http://youtu.be/NKsXdEf8vio (http://youtu.be/NKsXdEf8vio)

Since that version - I decided to try and do a PCB layout; which is done and almost ready to be sent off to be made into PCBs.

(http://2.bp.blogspot.com/-G5nQWXgTdJ8/UaR09DapsPI/AAAAAAAABac/t0y22NrQmVg/s1600/pcb_small.png)




Title: Re: Temperature Controller
Post by: blankfield on May 29, 2013, 03:49:36 PM
Really nice project, are you using bluetooth for rs232 communication? And what is the purpose of the xml format? Xml is a little to redundant format of data like for MCU's.
Title: Re: Temperature Controller
Post by: Mr Eastwood on May 29, 2013, 05:56:47 PM
Really nice project, are you using bluetooth for rs232 communication? And what is the purpose of the xml format? Xml is a little to redundant format of data like for MCU's.

Hi blankfield,    yes the Bluetooth module is for rs232;  all setup etc is done remotely via a custom console application written in c#.  The XML is only used to create the firing programmes on the PC;  it's then parsed and compiled into nice compact binary format that then gets sent to the controller:  but you're completely right - you wouldn't use XML natively on such a small MCU.    The push buttons I used were a bit crappy, but they should work ok for a while at least!
Title: Re: Temperature Controller
Post by: Mr Eastwood on July 22, 2013, 08:42:55 AM
Just another update;  my PCB's arrived this lunch from China;  so I quickly hand placed a few parts to check the foot-prints; it looks ok, so I'll proably get one soldered-up tonight after work - can't wait!!

(http://3.bp.blogspot.com/-Gs-hE0rBjCQ/Ue0lSm0E48I/AAAAAAAABf0/JRK9akeA5ng/s640/DSC02722_small.png)
Title: Re: Temperature Controller
Post by: MJLorton on July 22, 2013, 10:11:16 AM
Great to see your progress...do keep us posted!
Title: Re: Temperature Controller
Post by: Mr Eastwood on July 24, 2013, 12:19:23 PM
(http://1.bp.blogspot.com/-XcjKY13pw78/Ue_T2SSRUdI/AAAAAAAABgk/xsoqLrfyhnY/s1600/DSC02735_tiny.jpg)

I've now soldered up all the parts;  so all that is required is a stand-off connector for the Bluetooth module which I need to order and the board is complete!  Tonight I plan to power it up and get all the pots setup, and also check everything is working as it should.

Things left to do is to completely re-write the temperature profile editing PC software and to create a comprehensive operators manual and service document.
Title: Re: Temperature Controller
Post by: Mr Eastwood on July 27, 2013, 05:12:52 AM
Unbelievable!  it took 6 under-board wires and 2 track cuts and a 1 line change on the firmware to get it fully working;   well, at least I can move on now.
Title: Re: Temperature Controller
Post by: SeanB on July 27, 2013, 05:17:52 AM
So now on version 0.2 then. Glad you got it running without having to redo the board totally.
Title: Re: Temperature Controller
Post by: Mr Eastwood on July 27, 2013, 05:36:36 AM
Yup, 0.2 ;-)     when I did the boards I was so focused on messing up the footprints and drill sizes that I should have paid more attention to the layout.
Title: Re: Temperature Controller
Post by: SeanB on July 27, 2013, 10:06:35 AM
I see you also got the cable to the LCD slightly wrong, so the cable is incorrectly retained. That is a very easy mistake to make.
Title: Re: Temperature Controller
Post by: Mr Eastwood on July 28, 2013, 05:49:50 AM
I see you also got the cable to the LCD slightly wrong, so the cable is incorrectly retained.
thanks for spotting that,  I hadn't realized that until you said.
Title: Re: Temperature Controller
Post by: SeanB on July 28, 2013, 09:59:20 AM
Been there, did that, had to carefully undo the latches and undo the none openable tabs and then redo the cable as I only had the one connector.....
Title: Re: Temperature Controller
Post by: MJLorton on July 30, 2013, 12:32:52 PM
Thanks for showing us the progress AND the mistakes too...we all learn from that.

Hats off to sharp eyes Sean too!
Title: Re: Temperature Controller
Post by: Mr Eastwood on September 03, 2013, 06:24:23 PM
Last month I've been a bit side-tracked thinking about another electronics project,  but in the last few weeks I've managed to get the PC software almost complete along with some minor firmware changes.


The Software Installer.
(http://3.bp.blogspot.com/-MsGN9FEHFwE/UiZW78pmhII/AAAAAAAABlg/daatiKwJf70/s1600/KC1_Installer_1.png)



This is the Temperature Profile Editor.
(http://2.bp.blogspot.com/-SDi3BoyPCAg/UiZW8bu75SI/AAAAAAAABlY/vN1aaQf9zAQ/s1600/KC1_Profile_Editor.png)

Title: Re: Temperature Controller
Post by: Mr Eastwood on October 19, 2013, 06:11:58 AM
Last night I soldered a few more parts to the other boards;   I always used to enjoy soldering - but the novelty soon wears off when you have to add an extra cushion to your seat because your arse has gone numb!  :-)
Title: Re: Temperature Controller
Post by: Mr Eastwood on October 29, 2013, 09:00:01 AM
This is the child and pet friendly version wired-up to the kiln ;-)  last night I did a live test on a quick 3 segment temperature profile - and everything went well - so at the weekend I'll do a proper test firing to 960C with some slip-cast ceramics in the kiln.
Title: Re: Temperature Controller
Post by: Mr Eastwood on November 02, 2013, 01:24:57 PM
Well - I set the kiln running yesterday and it ran most of the day; this morning it was cool enough to take the work out, and everything worked great!  the controller ramped the temperatures almost perfectly;   I've really enjoyed making this controller and I've learnt so much along the way - so for the final post for this project,  here are some of the results ;-)


Title: Re: Temperature Controller
Post by: MJLorton on November 04, 2013, 10:21:44 AM
Brilliant! Hats off to you good man!
Title: Re: Temperature Controller
Post by: Mr Eastwood on April 20, 2015, 08:15:54 AM
Well it's been a while since I posted an update on this;  I recently got around to mounting it into a box and put it on the wall, also installing a suitable cable to the kiln; and it all seems to be working nicely.  here are some more finished pieces I've fired using it.





Title: Re: Temperature Controller
Post by: Mr Eastwood on November 01, 2015, 04:24:22 PM
(http://3.bp.blogspot.com/-uLcFXL_7T3Q/VjaATqGObzI/AAAAAAAACwo/xwZd0Xs4iu4/s640/DSC03866_small.jpg)

Last week I bought a 30 transformers for 12 from Ebay for my kiln controller boards;  I was really surprised how heavy the box was.
Title: Re: Temperature Controller
Post by: SeanB on November 01, 2015, 11:51:00 PM
They are heavy as they contain actual copper and steel transformers, which probably will still work in 30 years, unlike the modern built down too far SMPS units.

I actually have gotten equipment where the power supply is a SMPS ( cheap and nasty self oscillating one with regulation of around 30%) on a board with a footprint to replace the semi standard small transformer directly. Has an output of around 9V, but depending on load it varies from 6V at 500mA to 12V at no load.
Title: Re: Temperature Controller
Post by: Mr Eastwood on September 10, 2016, 08:15:32 AM
Just an update - I've been really quite busy with other things so my electronics hobby has taken a bit of a backseat ride;  so recently I've taken the time pick this back up again.  When I had the boards made I swapped out a couple of pins on the microcontroller in order to make it possible to use a larger chip without having to respin the board design;  so a few weeks ago I decided to re-write the entire project using a larger chip with a view to including all the extras features I wanted at the time but had to remove, because I ran out of programming space on the chip, as it was only 8K.

My original choice of replacement was the 18f4550 but after a while coding I then discovered that although the USB feature of the chip can be disabled - which was my original idea to free up the pins, one pin in particular of the USB can only be used in one particular direction,  so that made it incompatible without a messy board hack, so I turned to the 18f4685 with its 96K of code space and this looks like it might well work, and with its internal oscillator it will save me a couple of parts too.