# Add auto sleep function to soldering station

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#### Mixka

##### New Member
EDIT: Original problem was to make button presses momentary, but looks like it is not needed.

Hi all! This is my first post here. I'm total newbie and just starting electronics hobby.

Also english is not my native language and I have poor vocabulary.

My first project is to make my cheap soldering station more practical for adding auto sleep function.

Soldering station have 3 slot memory bank for tempatures which are selected by separate momentary switches. Looks like it don't have any effect if those switches are holded down.

I have sleep tempature saved to slot 1 and working tempature saved to slot 2.

I already have made simple mod, that when I put iron to holder it closes switch.

So now I need to make it press button 1 when I close circuit and press button 2 when I open it.

There should be short delay for setting work tempature (button 2).

There is 5V across switches.

Like this:
Circuit closed > Press button 1
Circuit opened > Delay 500ms > Press button 2

I think it is easiest to do with relay, but how to add short delay-off?

Or do I just buy cheap "multifunction" relay from China? Looks like function 10 is what I want:

(from 10:46)

Here is soldering station function video: https://1drv.ms/v/s!AkB2BxNSQ4E2jQdYjhf7FUxqmRpZ

-Mika

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#### aardyvarky

##### Member
Could you upload a picture of the soldering iron (with your switch)?

Could you also be clearer as to what you want?
e.g.
"1. When I take out the iron from its holder, I want it to wake to 'use' temperature.
2. When I replace iron in its holder, I want it to drop to 'sleep' temperature.
There is a switch mounted to holder that closes when iron is replaced..."

#### MrAl

##### Well-Known Member
Hi,

I would guess relays are the best here because you dont seem to have a schematic of the station circuit. You'd need that to make any other types of mods. As is, the relay has to be activated the same way the switch is activated which might mean a temporary closure or a continuous closure depending on how the station works.

#### crutschow

##### Well-Known Member
So you need a one-shot circuit controlling a switch/relay across each of the switches you want to activate.

Is the voltage across the switches you want to control, 5V?

#### aardyvarky

##### Member
Mika? Are you still there?
Question - by stuttering do you mean switch bounce?

#### Mixka

##### New Member
Sorry for long delay answer. I just investigate soldering station more and looks like there is no function for bank button long press, so this is easier now when momentary press is not needed. Now only function what is needed is relay delay-off. I updated start post.

#### aardyvarky

##### Member
Mika,

Entertaining though your video was (I've been forced to endure worse films), I still think we need to know more clearly what it is that you want. See my earlier post (#2).

#### Mixka

##### New Member
I was thinking that my updated start post was clear enough?

Of cource I can write your findings here to confirm it:
1. When I take out the iron from its holder, I want it to wake to 'use' temperature.
2. When I replace iron in its holder, I want it to drop to 'sleep' temperature.
There is a switch mounted to holder that closes when iron is replaced...

Here you go, even more entertainment for you https://1drv.ms/v/s!AkB2BxNSQ4E2jQdYjhf7FUxqmRpZ

#### aardyvarky

##### Member
Are you planning to switch the iron supply or the mains-side supply? Check that the relay can handle that voltage/current.
A picture of the iron plus a schematic plus the manual would be nice.

#### aardyvarky

##### Member
Ah that was useful. Yes I see what you want now. I think you will need two timers.
I'm sure both timers can be triggered by the same switch, so set one to press "1" and the other to press "2".
You can't hold buttons down because that puts the station into "set temp" mode.
It is possible to build a circuit to do it but for £9 (10 Euros?) it isn't worth the cost.

#### crutschow

##### Well-Known Member
There should be short delay for setting work tempature (button 2).
I see no particular reason for that delay.
Why do you think it's needed?

Below is the LTspice simulation a simple circuit that should do what you need.
It momentarily closes the Standby switch when the switch closes, and momentarily closes the On switch when the switch opens.

The circuit assumes that one side of each switch is connected to ground.
If not, then a different circuit will be needed.

The R_Sim resistors are for simulation purposes and should not needed in the actual circuit.

The transistors can be just about any N-MOSFET logic-level types that have their Rds(on) rated at a Vgs [not the Vgs(th)] of 5V or less as shown in their data sheet.

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#### Mixka

##### New Member
aardyvarky: I don't think that is big issue if it set to "set tempature" mode, because I don't need to adjust tempature. If I really need, I can unplug relay then.

crutschow: I need that delay because otherwise relay will goes on, off, on, off, on many times when I put iron to holder, because it is not that good made contact with iron and holder.

Thanks for schematic! Looks nice! I'm also finding software for scematics and looks like that LTspice is free? Is it useful to study?

#### crutschow

##### Well-Known Member
I need that delay because otherwise relay will goes on, off, on, off, on many times when I put iron to holder, because it is not that good made contact with iron and holder....
Okay.
I modified the circuit to add a debounce delay to the input by adding some Schmidt trigger NAND gates (used as inverters).
(The power and ground are not shown for the gates and must be connected. Also any unused inputs should be grounded).

I'm also finding software for scematics and looks like that LTspice is free? Is it useful to study?
Yes, LTspice is one of the best free Spice simulators available and is used by several on these forums.
It would be well worth your while to download and get familiar with it if you are interested in circuit design.

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