Automatic Coach lighting

[am549]

Sorry my electronics experience is pretty limited/non-existent (as you can probably tell!) so just trying to understand all the components and what they do (it's taking a bit longer to pick up than I thought).

Wasn't overly bothered about the time on, though the longer the better really.

Thanks for all your help with this, it's really appreciated!

[sagaguy]

Wow that looks awesome! Assuming there's a small hole drilled to get the wires for the battery compartment underneath?

Was hoping to use these LED strips for the lighting https://www.railwayscenics.com/bulb-cool-white-non-waterproof-led-strip-unwired-5mm-wide-p-2765.html as they can be cut to size quite easily and are easy to stick to the roof with a bit of double sided tape.

I keep seeing these 555 timers popping up during my reading around. I can see how they can be wired up to turn on from an instructables article, just struggling with the trigger for the reset and how much power they use when not in use

Here we are.

[Topcat2018]

sagaguy. There are basically two different types of 555 timer. The original, first designed back in the 1970s, uses bipolar technology. The output of these can sink and source quite large currents, but the quiescent current is about 12 mA, which is more than the continuous current that a CR2032 is rated for and will drain the battery in less than a day. They also won't work with a supply voltage less than 5 V, so are useless if you only have a 3 V battery.

Later designs (LMC555) use CMOS technology. They will operate with a supply voltage down to 1.5 V and depending on supply voltage the quiescent current will be around 100 to 200 uA. You can find 555 timer specs on the Texas Instruments website ti.com.

Depending on the LED current you want you may be able to drive the LEDs direct from the timer output rather having the timer drive a MOSFET, but with a MOSFET the voltage loss across the device will be almost zero, whereas with the LMC555 it could be 0.5 V, and you've only got 3V of battery voltage to start with.

The last circuit I posted, coach lighting circuit (4) will do the same job as a 555 timer but is simpler. The only difference is that the timing won't be as accurate as a 555 (but electrolytic capacitors have large tolerances anyway) and with the 555 timer the lights will snap off when the time delay has elapsed, whereas with the MOSFET only they will fade out gradually as C1 discharges and the MOSFET slowly turns off.

If you would like to let me know exactly how you are expecting your circuit to work (e.g. what's the reed switch for, what is the forward voltage drop of your LEDs, what LED current do you want) I can advise you further.

[RB51]

@sagaguy

My apologies. I was dealing with your duplicate posts in which the quote button had been used to respond to Topcat but in which I could not see any input from yourself and seem to have deleted them. I suspect there was a response from yourself.

Can you repost please using the reply box underneath the last post and not the white arrow in a blue box button which is a quote facility.

R-

[Topcat2018]

@RogerB. I would comment that it's not at all obvious that the up/left arrow is a quote facility. In fact it is conventionally used as an email reply symbol, so I'm afraid the Hornby forum has got it wrong. Also, as this is the first thing you see at the bottom of a post on the Hornby forum (not the "Reply" box) you naturally click on it to reply. Perhaps this needs changing.

[Brew Man]

I think it's been reported numerous times.

[sagaguy]

Fair enough,the coach lighting is switched on by running a small magnet along the roof which switches the latching reed switch on.By running the magnet along the roof again,it switches the reed switch off by unlatching it.As you can see,it`s very effective.

Ray.

[Topcat2018]

So why would you need a 555 timer? My original circuit did the same job electronically using a Hall effect sensor, but of course the problem is that you have to switch the lights on and off manually. That's why I switched to the idea of using a vibration sensor. The lights switch on when the coach starts moving and switch off after a delay when it stops moving.

[RB51]

@RogerB. I would comment that it's not at all obvious that the up/left arrow is a quote facility. In fact it is conventionally used as an email reply symbol, so I'm afraid the Hornby forum has got it wrong.

 

 

As Brew Man says we have discussed this button several times with the powers that be. It is not so much that they have it wrong, but more that the button is misused. Used as I have now [i.e. truncated text] it can be helpful particularly if the thread has moved on a bit, however if entire posts are replicated and they are long it can be tedious for the reader to plough through it all and find the new material. Additionally, if an image is contained within the quoted text then it and the response is held for moderation.

R-

[RDS]

@Topcat

Please read the thread at the top of the General Discussion section, 'Important Information for new members ....'