(Last-)Relay for simple circuit needed

Hi!

Here's what I want to achieve:
You open the door, and after 10 seconds, a device is automatically activated, for example, a light.

Okay, here's the translation:

'Here's what I'm looking for now:'
A time relay that switches the load 10 seconds after receiving power to the excitation coil, and is de-energized directly by disconnecting the power to the excitation coil via a switch. Does anyone know of such a relay and can provide me with sources where I can purchase it?

The following problem remains:
I want to connect the relay to the constant positive terminal (the energizing coil) and draw the ground connection through the door contact. However, if I close the door before the 10 seconds have elapsed, the relay will lose power and it won't happen... which is a bit silly.
Unfortunately, I'm not very knowledgeable about relay technology, so I don't know if there might be relays that already have a corresponding circuit integrated, something like a 'trigger.'

The most sensible approach would be to connect the excitation circuit to a constant positive voltage and ground it to a point on the car's chassis. The door contact should serve as the 'trigger' for the circuit. When 'triggered' (), the relay should activate a load output after 10 seconds; I would then deactivate it by removing the constant positive voltage and de-energizing the relay.

It would be great if someone knows something about that, I would be very grateful .

Greetings.

It's best to inquire with your local Bosch service center.
They usually have those kinds of time delays. They can sometimes be very expensive.

Well, I was already aware that they might be a bit more expensive. I'm just wondering if anyone has perhaps installed something similar before, or something along those lines, and could offer some advice.

Thank you.

Hi,

I think you'll have to build something yourself; it's unlikely you'll find a ready-made solution for that specific purpose, or it will be very expensive.

My first idea would be:

Bistable relay that can also handle continuous current, activated via a door contact and deactivated via a button.

It switches power through a large resistor to a larger electrolytic capacitor. A transistor then connects to this via a Zener diode (along with some resistors), so that when a certain voltage is exceeded, the working relay is activated. When activated, the bistable relay disconnects the circuit from the power supply.

The disadvantage would be that "out" won't work as long as the door is open, and that you need two relays. From a parts perspective, it would probably cost just over 5 euros, but you would need to think about the circuit design more carefully; what's described above is just the basic principle.

There's probably an easier way to do it, but I'm not really an expert in analog electronics.

Best regards,

Jan.

Hmm... Yeah... As a temporary solution, it probably could have been done that way, but for such a small benefit, it's a bit too much effort.

Nevertheless, thank you. We'll just wait and see; maybe one of our 'analog electronics' experts has an idea.

Greetings.

Hello,
I seem to recall pulling a relay like that out of a wrecked car at a scrapyard once. If the garage weren't so far away right now, I could give you the Bosch part number.
But I'd still like to try taking it to a junkyard. Usually, most of the relays are removed and end up in a large container. You could really spend some time browsing there.

Regards,
Andy.

This is a time relay with two independently adjustable times, featuring a delayed energizing function for 12 VDC.

Okay, please provide the German text you want me to translate. I will only provide the English translation.
e.g.: the RS-VR2 for 12 VDC, for approximately 30 euros + 16% tax.

Connect the excitation '+' terminal to 12 VDC. Connect the excitation '-' terminal to the positive terminal of the door switch via a standard diode, which then connects to ground.

'When the door is opened, the relay switches on after 10 seconds.' Your consumer.
The second contact activates the relay in a self-holding state after, for example, 1 second. This means it bypasses the door switch for the relay, and the relay remains energized until your off button opens the excitation circuit. The diode isolates the two 'ground switches' from each other.

Just a thought:

Years ago, CONRAD offered a DIY kit for an alarm system. It essentially used an NE555 chip with a relay output. The trigger was implemented by detecting a drop in the supply voltage, such as the brief dip that occurs when the interior lights are turned on. It cost 20 DM back then. The genius of it lies in this indirect triggering.

Hi!

Thanks, the idea about the special relay is great; that's exactly what I was thinking of. Unfortunately, they don't have a store near me, and, surprisingly, the part is quite expensive.

I was browsing Conrad's website and found the system you described as a DIY kit: Article number: 195456.

It now costs 30 DM, which is 16 €, but it's still cheaper than the relay. I'll go get it tomorrow and put it together.

Thank you again to everyone involved!

Greetings.