User question/suggestion

[aimlessfiddle]

HI,

Im trying to figure out the printing mode.
CLK sets the exposure time, what exactly does HLD do? If I set to HLD, it just pauses every .1 seconds. Not sure what its use is or how to use.

Also , this is very small trivial thing, but is it possible to make it where the audible beep sounds at the end of the second not the beginning? I keep track of time with the beeps, but the current way does not tell me how much time has passed, have to start counting from the second beep. Not sure if this is an issue with anyone else or if its just my hard head.
Thanks.

[aimlessfiddle]

The beeping is only an issue for me on the printing mode, other modes is not an issue.
Dry down compensation percentage?

[lo1ol]

Hello) Sorry for long answer.

Missed your question)

CLK sets the exposure time, what exactly does HLD do?

CLK -- stop/start printing by clicking on Print button
HLD -- print while holding Print button

Hold mode could be used if you make masks with pedal:)

[lo1ol]

Also , this is very small trivial thing, but is it possible to make it where the audible beep sounds at the end of the second not the beginning?

I can make this thing adjustable in UserConfig.h)

Btw, I chose making beep sound at the beginning, because

1. it's kind of confirmation for me, that I clicked "Print" button. It could be usefull, when display is turned off, for example, during color printing. Also some-time it could be not obvious by enlarger because it has lag time
2. I see end of the printing when enlarger turns off)

[lo1ol]

@aimlessfiddle Can you please check this new functionality on this version. If it's ok for you, I merge this changes to the main branch.

You need just create UserConfig.h file near to DarkroomTimer.ino with following content:

#define BEEP_MODE BEEP_ON_END

[ansel12800]

Hi Petr On the circuit diagram, there's a conflict: pin A4 is already occupied by the I2C display connection. It was supposed to be used for the relay. How can I change it to another pin? thank you so much!

…

________________________________ From: Petr Mikhalitsyn ***@***.***> Sent: Saturday, November 8, 2025 4:49 PM To: lo1ol/DarkroomTimer ***@***.***> Cc: Subscribed ***@***.***> Subject: Re: [lo1ol/DarkroomTimer] User question/suggestion (Issue #1) [https://avatars.githubusercontent.com/u/32206454?s=20&v=4]lo1ol left a comment (lo1ol/DarkroomTimer#1)<#1 (comment)> Can you please check this new functionality on this branch<https://github.com/lo1ol/DarkroomTimer/tree/beep-mode>. If it's ok for you, I put this change to the main branch You need just create UserConfig.h file near to DarkroomTimer.ino with following content: #define BEEP_MODE BEEP_ON_END — Reply to this email directly, view it on GitHub<#1 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/A3MEZDU3YUYSMKMKLAPZTHD33ZQNJAVCNFSM6AAAAACLBBY4XGVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTKMBWHE3DQOJXGI>. You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[ansel12800]

Sorry Petr, I used the old connection diagram. I see that it's changed with the I2C display version. However, I don't understand the pinout of the relay. It doesn't work if I connect the positive terminal of the relay to pin D4 of the Arduino. With a standard 3-pin relay, I connect the In1 pin of the relay to pin D4 of the Arduino and it works fine. I don't understand how the solid-state relay works with only two pins. Thank you.

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________________________________ From: Ansel Labonté ***@***.***> Sent: Sunday, November 9, 2025 10:33 AM To: lo1ol/DarkroomTimer ***@***.***> Subject: Re: [lo1ol/DarkroomTimer] User question/suggestion (Issue #1) Hi Petr On the circuit diagram, there's a conflict: pin A4 is already occupied by the I2C display connection. It was supposed to be used for the relay. How can I change it to another pin? thank you so much!

________________________________ From: Petr Mikhalitsyn ***@***.***> Sent: Saturday, November 8, 2025 4:49 PM To: lo1ol/DarkroomTimer ***@***.***> Cc: Subscribed ***@***.***> Subject: Re: [lo1ol/DarkroomTimer] User question/suggestion (Issue #1) [https://avatars.githubusercontent.com/u/32206454?s=20&v=4]lo1ol left a comment (lo1ol/DarkroomTimer#1)<#1 (comment)> Can you please check this new functionality on this branch<https://github.com/lo1ol/DarkroomTimer/tree/beep-mode>. If it's ok for you, I put this change to the main branch You need just create UserConfig.h file near to DarkroomTimer.ino with following content: #define BEEP_MODE BEEP_ON_END — Reply to this email directly, view it on GitHub<#1 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/A3MEZDU3YUYSMKMKLAPZTHD33ZQNJAVCNFSM6AAAAACLBBY4XGVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTKMBWHE3DQOJXGI>. You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[lo1ol]

Hello)

On the circuit diagram, there's a conflict: pin A4 is already occupied by the I2C display connection. It was supposed to be used for the relay. How can I change it to another pin?
thank you so much!

yeah, it was on old versions. New version uses D4 pin to control SSR:)

It doesn't work if I connect the positive terminal of the relay to pin D4 of the Arduino

Hm... It should work on any type of relay. I will recheck it on mine a little bit later

[lo1ol]

I rechecked it. For me it works the same way how it was on A4 PIN.

What kind of SSR do you have? It should be DC-AC SSR. How did you check that it works?

I don't understand how the solid-state relay works with only two pins.

minus input pin goes to the ground. Plus pin -- used to control SSR. When it 0 -- SSR is turned off, when it has 5V -- SSR is on.

OUTPUT pins works like a switch. When SSR is on -- they are connected. When SSR is connection is broken.

Notice, that you couldn't check AC SSR connection with multimeter. SSR could be checked with some AC load only.

Also SSR makes no click sound when it's turning on and off

[ansel12800]

Good morning Petr, thank you for your help. I mixed up versions 0.4.2 (standard display version) and 0.5.1 (with I2C display). That was my mistake. I'm sending you the two photos with the relevant parts highlighted. Regarding my SSR relay, it does indeed have three pins; that was also my mistake. So, the CH1 trigger pin isn't used, if I understand correctly. I only tested it with my multimeter probes to see if I got a beep when the relay switched off at the SSR relay's output terminals, and there was nothing. I deduce that a real current load is needed for it to function normally. Please look at the photos I sent (relay and graph). Have a good week and thank you so much.

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________________________________ From: Petr Mikhalitsyn ***@***.***> Sent: Monday, November 10, 2025 1:18 AM To: lo1ol/DarkroomTimer ***@***.***> Cc: ansel12800 ***@***.***>; Comment ***@***.***> Subject: Re: [lo1ol/DarkroomTimer] User question/suggestion (Issue #1) [https://avatars.githubusercontent.com/u/32206454?s=20&v=4]lo1ol left a comment (lo1ol/DarkroomTimer#1)<#1 (comment)> I rechecked it. For me it works the same how it was on A4 PIN. What kind of SSR did you bought? How do you check that it works? I don't understand how the solid-state relay works with only two pins. minus input pin goes to the ground. Plus pin -- used to control SSR. When it 0 -- SSR is turned off, when it has 5V -- SSR is on. OUTPUT pins works like a switch. When SSR is on -- they are connected. When SSR is connection is broken. Notice, that you couldn't check AC SSR connection with multimeter. SSR could be checked with some AC load only — Reply to this email directly, view it on GitHub<#1 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/A3MEZDS6OT4WNHTY23WVDTT34AU2XAVCNFSM6AAAAACLBBY4XGVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTKMBZGYZDCNBVGE>. You are receiving this because you commented.Message ID: ***@***.***>

[lo1ol]

@aimlessfiddle do you tested BEEP setting? Is it ok for you? Do I need to add this setting to main version of firmware?