Hall effect LED switch control Circuit board breakdown

[peteski]

You are full if ideas John! 
Rechargable battery adds another layer of complexity. You would need a charging circuit which I assume  would use DCC power from the track to charge the battery (without blowing it up).      Otherwise you would have to touch the car to plug it into some dedicated external charger.

If you are planning on having power from the track available in the car, why not just power the circuit directly from the track?  As shown, you are familiar with using a bank of tantalum caps to prevent flicker, and you coudl still use the Hall switch to turn them on or off.  Easy-peasy, and nice and simple. No battery swapping either.

[Lemosteam]

Hi Pete. All I need is a charging device that can plug onto the tabs of the battery, off the track.  After that, then re-plug the lights onto the battery, so no need to replace batteries, unless on fries.  Still no track power.

[peteski]

Hi Pete. All I need is a charging device that can plug onto the tabs of the battery, off the track.  After that, then re-plug the lights onto the battery, so no need to replace batteries, unless on fries.  Still no track power.

So you still have to handle the car, albeit less frequently than switching the lights on or off.

Why are you avoiding using track power?  It it because the trucks you use do not have power pickup ability?

Also a heads-up on the rechargable battery's capacity - it is only 11mAh (a standard non-rechargable CR927 battery has a capacity around 30mAh) so you will be recharging the battery more often than if you were to replace CR927.

I am curious about the current your LEDs consume because the specified maximum continuous discharge rate for CR927 is only 0.4mA, and the rechargeable battery's is  0.8mA. It has life rated for 100 100% discharge cycles.  This type of a battery is mainly used as a memory backup power where the power drain and depth of discharge are very low.

[Sumner]

Hi Pete. All I need is a charging device that can plug onto the tabs of the battery, off the track.  After that, then re-plug the lights onto the battery, so no need to replace batteries, unless on fries.  Still no track power.

Don't know if the following link will work for you or give you ideas or not....

https://1fatgmc.com/RailRoad/DCC/page-43.html

I plug into my sound boxcar to charge it and have a slide switch that changes the battery from charging to use for the sound. 



Using a dark car N scale car and with the car a foot or more away on the layout the switch and plug are hardly noticeable.  If you use the Hall Effect you might not need the switch but also the switch and plug could possibly be put on the underside of the car.

I built a charging circuit ....



... from a 3 stage Adafruit charging board (bottom right above).  It works great and I use similar ones inside of my WiFi wireless throttles to charge them.



I got some really small connectors ( HERE ).....

... but didn't use them but they might work for someone really trying to hide them.

Sumner

[Lemosteam]

So you still have to handle the car, albeit less frequently than switching the lights on or off.

Why are you avoiding using track power?  It it because the trucks you use do not have power pickup ability?

Also a heads-up on the rechargable battery's capacity - it is only 11mAh (a standard non-rechargable CR927 battery has a capacity around 30mAh) so you will be recharging the battery more often than if you were to replace CR927.

I am curious about the current your LEDs consume because the specified maximum continuous discharge rate for CR927 is only 0.4mA, and the rechargeable battery's is  0.8mA. It has life rated for 100 100% discharge cycles.  This type of a battery is mainly used as a memory backup power where the power drain and depth of discharge are very low.

Hi Pete, its not about handling the car.  Its about removing the roofs.  These cars have custom painted Shapeways roofs with glued on windows that I don't want to damage. 

This is why I want the battery outside the car.

So the rechargeable battery is out due to its short life/recharge span.  The trucks are custom Shapeways 2DP5's with no electrical pickup and no intent to make them do so or to connect a recharge circuit.

I actually really hate that battery holder in the image above as its so huge, so maybe:



I've made a battery holder for this in the past and I can recreate it and mount it atop the centerbeam of the floor, behind the underbody boxes. Could be easy to make a negative pin disconnect when not in use.

https://www.digikey.com/en/products/detail/dantona-industries/LITH-79/17827950

So would the battery above, and the circuit below work without the MOFSET, and would the Hall switch drain it over time if left connected?

[peteski]

Yes, that circuit should work John. You don't need that R1- the LEDs create the electrical load connected to the positive voltage.

[Lemosteam]

Ok, so I bought some hall switches and Attempted this.

The lights work without the switch at the brightness I want when I connect my handy tester.



Then I added the hall switch to the circuit.



I turned on the power from the handy tester, no lights. Perfect. Floated a fairly strong rare earth magnet over the switch, and the lights turned on briefly, and then faded and off. Tried the same magnet several times, nuthin. Tried larger magnets, nuthin.

Battery is still good.

Magnet too weak?

What did I do wrong?

Could I have fried the switch? I had to unsolder and resolder several times before I got the pins right.

Did I buy the wrong switch?

This is the switch: https://www.digikey.com/en/products/detail/infineon-technologies/TLE4906KHTSA1/2023079

In the immortal words of Charlie Brown: Auuuugggghhh!

[peteski]

You seem to have bought a non-latching Hall switch.  According to the data sheet, it only stays on when the South magnetic field is present.
You need a latching Hall switch.  The switches mentioned earlier in the thread were the latching type.  Like the one you found earlier in this thread: https://www.digikey.com/en/products/detail/diodes-incorporated/AH1911-W-7/9674237

[Lemosteam]

Well, @#$%)E#^!!!

Thanks for helping, and the link.  Replacements ordered.

[Lemosteam]

Bought the suggested Hall switch, did the exact same thing.  Ugh.  Lights for a brief second and then fades, and will not relight with a magnet.

[Sumner]

Looks like if that one doesn't do it look for one that meets this criteria ( HERE ) .

Looks like you use one pole of the magnet to turn it on and the other to turn it off.  Is there any chance with the one you are trying now that you are using the wrong pole to turn it on?

Sumner

[peteski]

Bought the suggested Hall switch, did the exact same thing.  Ugh.  Lights for a brief second and then fades, and will not relight with a magnet.

Sorry about that John.  The descriptions of those devices don't seem to be very clear.  I did some additional searches and found a device which can be turned on and off by flipping the polarity of the magnet.
https://www.sparkfun.com/hall-effect-sensor-us1881-latching.html
Looks like Digikey also carries them.
https://www.digikey.com/en/products/detail/melexis-technologies-nv/us1881eua-aaa-000-bu/431867

[Lemosteam]

Hi Pete, no worries.  I can sell the extras to you, lol. 

Only issue with this one is the voltage range, it states 3.5v-25v on the specs.  The cylindrical batteries above are 3v so they may not work??

I might just go back to the external slide switch with a disconnect inside the car.

Question about those 1mm pitch pin /socket connectors you like to use.  Is the plastic housing around the pin glue-able like styrene or is it a Delrin or nylon material?  I would like to flip the pins and sockets to make them a mistake free connection but cutting and gluing two in opposite directions.  Can you share a link?

[peteski]

John,
It might work on 3V but it is not guaranteed. Here are couple which work on lower voltages.
https://www.digikey.com/en/products/filter/switches-solid-state/565?s=N4IgjCBcpmAMVQGMoDMCGAbAzgUwDQgD2UA2iAMwBs1ArAEwgC6hADgC5QgDK7ATgEsAdgHMQAX0L0A7FUQgUkDDgLEyIACwAOLdISFaVAJxg5B6VrgRzliiANUtR6czadIPfsLGTwYegjQCmhYeIQkkOT02rRGWvYg0hSGGq4gHFy8gqIShGBxRvKKymFqkSAITL4AtLRFISrh6oyEdlWE1YxBivwArqoR5HVVvl3kABZYmAAEuKiouEjs09gA7gLsSOPM4kA

Unfortunately these are tiny (leadless) surface-mount devices with small solder pads.
Mouser Electronics might have something in larger packages.  Might take a look later.

Those headers/sockets use glass-filled plastic. Specs call it Polycyclohexylenedimethylene Terephthalate (PCT), Polyester.  It does not take plastic cements well, CA works ok, but best would be to use JB Weld standard long-setting-time epoxy.  As for making them polarized I sometimes use a trick where I use a 3-pin connector. I wire the outside pins together and make it negative, and the center pin is positive (or the other way around). That way the connector will work plugged in either way.  Yes, 3 pins make it a bit larger, but that makes it non-polarized.

Here are Digikey part numbers for them    
ED8450-ND
ED8250-ND

And double row:
85393-05010001000-ND
85210-05010001000-ND

[delamaize]

Thought I'd dig this one up again, and share my findings.
I took a gamble on a eBay seller out of China called "WeHonest" on a battery powered lighting kit.
https://www.ebay.com/itm/401412108056

At about $10 each before shipping, they are not the cheapest option, although not too bad, But the shipping seems to stay fixed. For instance, I ordered 5 the last time, and shipping was only $8, and it only took about 2-2.5 weeks.

Why do I bring these up? Battery options.

I'll get some pictures when I get home after work, the battery holder is not attached to the main board. It is it's own board, that can be either connected to the main board via a 2 pin plug, or they include a jumper wire, which is like 4-6 inches long.
The existing battery holder is for a small, flat coin cell, that is 3 volts, a CR1216 IIRC, But, I can tell you that other combinations of batteries do work also. For instance, On the first batch I installed, I used some of LR41, 2 cell holders I had in the parts box, after changing out the recalled caboose lights on my Rapido Wide vision cabooses. I simply soldered the wires from one of the jumpers to that holder, and was able to mount the batteries in a place where I was happy with them. Again, I'll take some pictures later today. I'm thinking that a battery, Like the LITH-79 John mentioned earlier, Might work, and could be hidden outside, on the bottom of the car.

Another feature I like is the ability to dim the lights with a push button. I need to play with the latest batch of boards, But I believe that the jumper might tie into the dimmer button, allowing for a remote button to be mounted/hidden outside the car to allow the brightness to be changed without accessing the board directly. I did discover that the empty 2 pin port in the middle of the board does connect to both ends of the Reed switch, and bridging that connection temporarily will cycle the lights. This would allow for a momentary on/off button to be mounted somewhere to turn the lights on and off, without using the reed switch

Like I said earlier, I will get some pictures later, and I'll experiment a little, and report back, But as of now, I'm really happy with these kits.