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DIY Soldering Station


Arv Evans
 


bigdswitzer
 

Nice find Arv, thanks for all you contribute 


Zvi Segal
 

You are lucky with the temp sensor.

There some soldering handles WITHOUT sensor.

They measure the resistance of the heating element by switching the heating  element between power and resistance monitor.

Anyway, nice project.


--
Zvika 
4Z1ZV


Tom, wb6b
 

On Wed, Mar 3, 2021 at 11:19 AM, Zvi Segal wrote:
They measure the resistance of the heating element by switching the heating  element between power and resistance monitor.
What an interesting idea. As a fun project I wonder how well this would work to control the temperature of an old generic soldering iron I have laying around. Building some kind of circuit that can switch the AC voltage to the heater yet measure small resistance changes, likely have a microprocessor for PID calculations and temperature display, and not be a shock hazard would be interesting. 

Tom, wb6b


Jerry Gaffke
 

Tom,

>  As a fun project I wonder how well this would work to control the temperature
>  of an old generic soldering iron I have laying around. Building some kind of
>  circuit that can switch the AC voltage to the heater yet measure small resistance changes, 

No need to switch.
Just measure both voltage and current simultaneously to measure the resistance,
then modulate the voltage (or current) for your target resistance.
Nichrome does not have a large temperature coefficient for resistance, so the
heating element resistance may not change a lot.  Worth trying, cool if it works!
    http://www.brysonics.com/heating-a-nichrome-wire-with-math/
Or could strap a thermocouple to your old iron.
But using a Hakko clone for $5 with sensor included seems more practical.

Regarding the DIY article that Arv pointed out, it says:
"if I were to connect the voltage divider sensor directly to the analog pin there will be gaps
between the temperature readings (Ex: 325°C, 326°C, 328°C..... 327°C is missing)"

That seems a bit over the top.
I doubt most of us need the op amp, reading it within 10C should be fine.
You will have greater temperature differences between tip and sensor once you
touch the tip to something that sinks heat, such as something you want to solder.
If you really care, get a modern uC with an extra bit or two in the ADC.

I'd tend to add some sort of protection to that ADC pin (perhaps a resistor and a zener)
so it doesn't go beyond 5v.

As he notes in the article, a fancy PID algorithm doesn't add much here.
The thermal inertia of the iron would make that overkill.
I suspect you could get by with just a pot (knob calibrated in degrees C)
to set the reference voltage, plus a comparator.
I may have to try that!

Good that he figured out the Hakko handheld units, especially with clones at that price.
A DB9 connector might be a good cheap connector for this, 3 pins each for
power and ground to the element, plus 1 pin each for the two sensor wires and safety ground?.

Here's an interesting discussion up on eevblog:
   https://www.eevblog.com/forum/reviews/hakko-907-clone-with-silicone-handle-(fakko-907)-e-bay/
A good read, if only to see them refer to the clones as "Fakko".

An IRF510 is good for 5 Amps, so could be sufficient here.
Though would need to drive that gate to nearly 10v.

Could use your bench supply for the 24vdc.
You aren't whacking at your gear when it's powered up, are you?
A couple 12vdc 2amp wall warts from a second hand shop in series would be sufficient,
assuming they don't tie the negative output wire to frame ground like some do.

Jerry, KE7ER


On Thu, Mar 4, 2021 at 09:46 AM, Tom, wb6b wrote:
On Wed, Mar 3, 2021 at 11:19 AM, Zvi Segal wrote:
They measure the resistance of the heating element by switching the heating  element between power and resistance monitor.
What an interesting idea. As a fun project I wonder how well this would work to control the temperature of an old generic soldering iron I have laying around. Building some kind of circuit that can switch the AC voltage to the heater yet measure small resistance changes, likely have a microprocessor for PID calculations and temperature display, and not be a shock hazard would be interesting. 
Tom, wb6b


Jerry Gaffke
 

For those not needing another project, just buying a temp controlled soldering iron might be an option.
There are complete kits that use the Hakko style irons for around $25:
    https://www.ebay.com/itm/936-Rework-Iron-Soldering-Station-ESD-SMD-Welder-Welding-Wire-Sponge-Tips-110V/361306580500


Tom, wb6b
 

On Thu, Mar 4, 2021 at 01:48 PM, Jerry Gaffke wrote:
But using a Hakko clone for $5 with sensor included seems more practical.
I had no idea that clone handles existed and only cost around five bucks. That would be a good starting point for such a project. The only reason for switching off the heater during temperature measurement would be to let it settle to closer to the actual soldering tip temperature, as I imagine while power is applied the temperature of the heating element wire will be significantly above the tip temperature.

Still sounds like a fun little project, either the generic iron or Hakko route. Maybe I could haywire something very simple just to see if the generic iron version would work at all. 

I have a venerable old Weller digital display soldering iron. After buying it way back when, it took me a long time to no longer be bothered when seeing the temperature changing on the display. Seems like I was happier not knowing, like with the magnetic tip switch controlled tip Weller irons. 

I have resisted (barely) the idea of improving my digital display Weller with new microprocessor technology. It melts solder just fine. 
And I tend to crank it up and down, with the old school knob, frequently based on muscle memory and how big of an area it needs to heat at any given time. 

Tom, wb6b


Tom, wb6b
 

On Thu, Mar 4, 2021 at 01:48 PM, Jerry Gaffke wrote:
Worth trying, cool if it works!
    http://www.brysonics.com/heating-a-nichrome-wire-with-math/
Interesting article, thanks.


Patrick Pugh Sawian
 


Tom, wb6b
 

On Fri, Mar 5, 2021 at 12:28 AM, Patrick Pugh Sawian wrote:
Built mine years ago here 
Looks cool. Is there a link to more build info?

I googled VU3PAT soldering station that gave a link to "pcbheven" that starting spawning "congratulations your are the five millionth search and click here for your big prize" following up with "click here to update your flash" and producing a chain of these redirected malware links almost faster than I could back click out of there. 

It looks like your station has a vacuum part pick. That seems like a cool thing to have. I sometimes tack one side on small SMD devices to a piece of thin bus wire, then tack another side/pin to the solder pad on the board. Then go over the pins again to make the final soldering neater. A vacuum pick sounds better.

Also, I would like to find an inexpensive vacuum pump operated solder sucker. I have one of the original spring loaded solder suckers, but the ballistic action and recoil at times has removed the pads as well.  

Tom, wb6b


 

I like it but lack of thermal runaway and other safeties would make it a fun project. If I were to build one safety is a must. I looked through the code and its pretty small so adding it might be worth it down the road but I just bought a dual channel Weller the day before you posted this hihi.
--
David

 N8DAH
https://kit-projects.com/

Shop is open!


Patrick Pugh Sawian
 

Hi Tom,

Thank you for your compliments. Sorry I do not have a build log for any of my projects as I often build on the fly. Whatever was built then was from here Homemade Soldering Station to whom all the credit goes to.  Am sure there are a lot of better PID duino designs now, but back then PIC was all we played with. Yes the vac pick is a nice cheap add on when you're dealing with SMDs particularly, and it had to be hooked to my shop vac through a diverter and clamped smaller hose to work. A cheap foot switch (available widely in sewing machine stores this neck o the woods) is used via a triac to switch the shop vac on and off when picking or desoldering stuff.


73ees.
Patrick
VU2OGA (Ex VU3PAT)

PS:- Careful with the malware. Greece is in a crisis.