"sensorless" soldering iron temperature control - diyAudio
Go Back   Home > Forums > Design & Build > Parts

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 24th May 2009, 01:37 AM   #1
star882 is offline star882  United States
diyAudio Member
 
star882's Avatar
 
Join Date: Mar 2007
Default "sensorless" soldering iron temperature control

Could the resistance of the soldering iron be measured to determine its temperature? (Assume it's just a normal soldering iron without any fancy controls.) A PWM circuit can be used to control power and the resistance could be measured during the off cycle.

I'm designing a "magic box" that the soldering iron plugs into that makes the iron temperature regulated, without having to add a temperature sensor. Just calibrate it whenever a different iron is used.

Taking it a step further, it could potentially be used for any heating appliance without motors or electronics.
__________________
"Fully on MOSFET = closed switch, Fully off MOSFET = open switch, Half on MOSFET = poor imitation of Tiffany Yep." - also applies to IGBTs!
  Reply With Quote
Old 24th May 2009, 01:40 AM   #2
Magura is offline Magura  Denmark
diyAudio Member
 
Magura's Avatar
 
Join Date: Oct 2003
Location: Denmark, Viborg
A simple way of measuring the temperature, would be to simply measure the current draw of the heating element.

Magura
__________________
Everything is possible....to do the impossible just takes a little while longer.
www.class-a-labs.com
  Reply With Quote
Old 24th May 2009, 02:17 AM   #3
star882 is offline star882  United States
diyAudio Member
 
star882's Avatar
 
Join Date: Mar 2007
Quote:
Originally posted by Magura
A simple way of measuring the temperature, would be to simply measure the current draw of the heating element.

Magura
Main problem is having to account for supply voltage variations. It would be more complex than putting a current regulator in parallel with the PWM transistor and S&Hing the voltage across the load during the PWM off period.

It would work nicely if the supply is regulated, though. In that case, S&H the current during the PWM on period.
__________________
"Fully on MOSFET = closed switch, Fully off MOSFET = open switch, Half on MOSFET = poor imitation of Tiffany Yep." - also applies to IGBTs!
  Reply With Quote
Old 24th May 2009, 08:44 AM   #4
Elvee is offline Elvee  Belgium
diyAudio Member
 
Elvee's Avatar
 
Join Date: Sep 2006
It could be a good idea, but with the usual materials of the heating element, it will be difficult: these alloys have in general a near zero tempco, with a sign inversion around 350°C. This makes the design of a controller very difficult.
On the other hand, self-regulating heating elements do exist: they rely on the PTC properties of special materials, and are used in hot melt guns for instance.
One could probably make a soldering iron based on such an element.
  Reply With Quote
Old 14th January 2014, 06:57 AM   #5
diyAudio Member
 
Join Date: Sep 2011
any progress on this?

is it true tip-temperature is proportional to current-draw?

thx
  Reply With Quote
Old 14th January 2014, 07:15 PM   #6
AuroraB is offline AuroraB  Norway
diyAudio Member
 
AuroraB's Avatar
 
Join Date: May 2001
Location: Norway, -north of the moral circle..
I think Elektor had a design that measured the resistance of the element itself, but it was some years ago. Couldn't find it though.....
__________________
While the Lie leapt from Bagdad to Constantinopel, the Truth was still looking for it's sandals!
  Reply With Quote
Old 19th January 2014, 03:53 AM   #7
dangus is offline dangus  Canada
diyAudio Member
 
Join Date: May 2004
Location: Vancouver Island
If you have an iron that runs too hot most of the time, try a light dimmer. It won't regulate the temperature, but it will reduce the temperature to a more reasonable range for most purposes, and make tips last longer. If you have an infrared thermometer, you could roughly calibrate the dimmer dial.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
"TECHNO"Amp building in progress-using "Iron Method" zox2003 Solid State 23 30th March 2010 08:42 PM
What makes an amplifier "bright", "warm", or "neutral"? JohnS Solid State 51 13th December 2009 06:42 PM
The "Leap-Frog" Method Of Switching Amplifier Control Loop Design analogspiceman Class D 29 1st December 2006 03:21 PM
"Start me up..." AlephX with relais control and powermanagement. joho Pass Labs 26 22nd December 2005 02:47 PM
"non direct" volume control Glass_painter Tubes / Valves 2 25th September 2003 07:09 PM


New To Site? Need Help?

All times are GMT. The time now is 03:01 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2