Grav Charge Problems - HELP!?

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ProfCoppersmith

New Member
So, working on some Grave Charges for my custom Mando armor. I got a set of static ones from Etsy. They were some what disappointing due to a possible translation issue (they came from Italy, and the info was clearly put through Google Translate). They look good, but aren't made of aluminum as I was let to believe. So I'm currently planning to use them as blanks for molds, so I can remake them in aluminum. I'll use them as stand-in's until then (they also need to be sealed, the maker used Rub-n-buff, but didn't seal it after wards, so they leave silver smudges everywhere). So this problem has been solved. ^_^

The real problem I have is this: I also found a set of flashing LEDs that are perfect, except that they are turned on/off by a magnetic field rather than a push button (the amazon description didn't mention this). Here's a short vid of the light(s), and the issue with them.


Anyone have a suggestions as to where to find lights like this, similar pattern of red LED's, that activate with a push button? Like a push light? Relatively cheap?
 

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ProfCoppersmith

New Member
Recasting is frowned on here. Make a mold of someone else's work is not a good idea.
Then I can take the dimensions and turn them out on my lath once I get it fixed. Also, after looking at them some more, I don't know how well they would work for mold making anyway. I was namely planning on the recasting idea because I am a little more likely to be able to do that sooner, and it would save time on a personal project. Not a big deal for me to switch methods. ^_^
They're only for my personal use, no intention of selling them, or claiming them as my work. I didn't think it would be that big of an issue. So, sorry on that front.

Have you got any advice about the issue with the electronics I was asking about?
 

neophyl

Well-Known Member
Cheap magnetic sensors are usually just a reed switch. If you can figure out the connections you could just replace it with a normal switch. Can you post detailed sharp pics of both sides of the board. Someone might be able to figure out from that.
 

ProfCoppersmith

New Member
Cheap magnetic sensors are usually just a reed switch. If you can figure out the connections you could just replace it with a normal switch. Can you post detailed sharp pics of both sides of the board. Someone might be able to figure out from that.
Here's the best I can do for closeups of the board. My phone is the best camera I have right now, so sorry if it's still a bit blurry.
IMG_0049 (2).jpeg


Hope this is clear enough. And thank you! ^_^
 

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neophyl

Well-Known Member
Some of it I can make out. The battery positive goes through the metal contacts and down to the chip side of the board through the soldered points on either side. From the left contact there is what looks like a 100 ohm resistor supplying a track that has all the leds positive anodes connected to it. The leds then all connect back to individual pins on the 8 pin microchip. That's what will be turning them on/off.
On the micro Pin 1 (near the little dot) is usually connected to positive and pin 8 Negative. As pin 8 has a pad with 3 little dots I think that connects using vias to the other side of the pcb where the negative contact will be. Which lines up with common pin outs.
The 3 pin component could be several things, it could be some form of transistor/mosfet, or a voltage regulator, but hall effect sensors also come in those packages too and the micro doesn't need a mosfet for driving the leds (its not connected like that either so I think the chances are very small) and as its running from a coin cell I really doubt its a voltage regulator. Its 3 connections look to be to positive, the other goes to a pad that has 2 tiny holes in it which I think are more small vias and connect to the battery negative contact on the other side of the pcb) which would leave the third pad between it and the 8 pin chip to be connected to the Micro . I think that is being used as an input. Inputs on most micros can be programmed to be activated by either being connected to positive voltage or by being connected to ground. Ground being more common (for several technical reasons which I wont go into here :) )

I take it there's nothing under the coin cell except for some pcb/contact surface for the battery and there no other component(s) on the battery side ?

How cheap are these things ? if cheap I would be tempted to experiment. As its pictured the bottom left of the 3 pin component is what I think will be the line connected to the micro. If you briefly connect it to the other legs on that part one at a time. The one above it is vdd (positive) so connecting to that would see if a positive impulse kicks it in gear. If it doesn't then connecting it to the pad on the right (the negative) would be the next step to see if a negative trigger is whats needed. One or the other might elicit a response. I'd try the ground connection first.

There's a slim chance the 8 pin micro has some form of built in hall effect sensor which means you would be out of luck but if they aren't expensive then its worth a try.

Oh I forgot to mention if trying to trigger it by connecting the pins make sure its not properly triggered so have the magnet near it. Cant tell if connecting them will trigger it if its already triggered.
 

E Williams

Sr Member
RPF PREMIUM MEMBER
Hall effect sensor in that 3 pin package would be my guess too. Neophyl sounds much more versed in this stuff than I am but the advice about experimenting with shorting the different legs to themselves and ground is exactly what I would suggest too. Depending on if the sensor is used to trigger the animation sequence or as simply a cut-off, you may be able to get away with just removing that part or cutting a trace and installing your own switch -- is my thinking here correct, neophyl?

What were these little boards originally? Based on your video their animation seems perfect for these Mando charges.
 

ProfCoppersmith

New Member
What were these little boards originally? Based on your video their animation seems perfect for these Mando charges.
Warning/visibility lights to put on the inside of a car door. The idea is that you attach one to the outer edge of the door and a magnet on the door frame across from it. So they activate when you open the door (HERE'S the link to them on amazon if you wanna take a look). Pretty nifty, I think, but perfect for these... if I can rework the switch.

(aaaaand I just realized: if I had been paying attention when I bought them, they DO state that they use "magnetic sensors" to turn off. oh well. -_-' I feel kinda dumb now.)
 

E Williams

Sr Member
RPF PREMIUM MEMBER
If you end up not being able to bypass the sensor, maybe instead you could make a stand resembling the piece the charges are stored in on Mando's belt, and add the shut-off magnets to it?
 

ProfCoppersmith

New Member
If you end up not being able to bypass the sensor, maybe instead you could make a stand resembling the piece the charges are stored in on Mando's belt, and add the shut-off magnets to it?
I had thought of that, and that's definitely a possibility. Though that would mean the charges themselfs would no longer stick to anything else. Maybe I could find another means to do that?

I take it there's nothing under the coin cell except for some pcb/contact surface for the battery and there no other component(s) on the battery side ?

How cheap are these things ? if cheap I would be tempted to experiment.
Correct, it's just a contact point.

$12 for 4 of them. So relatively cheap, but not dollar store cheap.
 

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neophyl

Well-Known Member
Well I'm in the UK so the amazon link couldn't be directly used. However I did find a UK seller and ordered some, £6.99 for 4. They arrived today. The ones I received the pcb is laid out very slightly differently but the same components are there. The main difference each led has its own resistor which electrically is a better design than all 5 using a single one.

On the ones I got if I bridged the signal pin that goes between the hall sensor (the 3 pin component) and positive the circuit is triggered. As such if you wire a switch between those 2 points then activating the switch OR removing the magnet makes it go.

If you don't want a magnet to trigger it at all then you could remove the hall sensor and just fit a switch in its place.

It does mean I can still use the magnet to stick the thing to a metal surface instead of the sticky pad included and still trigger it with the switch. So great buy really and thanks for the heads up :)
 

ProfCoppersmith

New Member
Well I'm in the UK so the amazon link couldn't be directly used. However I did find a UK seller and ordered some, £6.99 for 4. They arrived today. The ones I received the pcb is laid out very slightly differently but the same components are there. The main difference each led has its own resistor which electrically is a better design than all 5 using a single one.

On the ones I got if I bridged the signal pin that goes between the hall sensor (the 3 pin component) and positive the circuit is triggered. As such if you wire a switch between those 2 points then activating the switch OR removing the magnet makes it go.

If you don't want a magnet to trigger it at all then you could remove the hall sensor and just fit a switch in its place.

It does mean I can still use the magnet to stick the thing to a metal surface instead of the sticky pad included and still trigger it with the switch. So great buy really and thanks for the heads up :)
No worries! Thanks for the advice on modifying them.

On that note, would you be able to post a picture of said modification? I'm still new to electronics, most of my background is in mechanical movements and the like. So having a finished version to reference really helps. ^_^
 

neophyl

Well-Known Member
A picture of the one I got wont do you much good as the placement is different as I mentioned.

Using your picture though with some added markings -
amazon door flasher.jpg

If you are leaving the magnetic triggering in place but you want to add a normal switch to trigger it too then all you do is wire the switch up between Points A & B. A is the track that goes back to the micro and B is positive voltage.

If you want to remove the magnetic activation its a little more complicated. First of all you remove the 3 legged component that is in the middle of a/b/c. That is the hall sensor that detects the magnetic field. You then have to wire the switch between A & B like before to trigger it. You also need to add something like a 100K resistor between points A and C. C is ground/negative on the battery and the other leg on the hall sensor. Sorry its placed a bit far over the paint program didnt exactly give me a lot of fine control. This keeps the pin low when the switch is not active and stops the pin voltage from 'floating' and triggering when its not supposed to. 100k ohm is not vital, its just a pull down resistor. Anything from 10K to 220K should probably do the same job.
 

ProfCoppersmith

New Member
A picture of the one I got wont do you much good as the placement is different as I mentioned.

Using your picture though with some added markings -


If you want to remove the magnetic activation its a little more complicated. First of all you remove the 3 legged component that is in the middle of a/b/c. That is the hall sensor that detects the magnetic field. You then have to wire the switch between A & B like before to trigger it. You also need to add something like a 100K resistor between points A and C. C is ground/negative on the battery and the other leg on the hall sensor. Sorry its placed a bit far over the paint program didnt exactly give me a lot of fine control. This keeps the pin low when the switch is not active and stops the pin voltage from 'floating' and triggering when its not supposed to. 100k ohm is not vital, its just a pull down resistor. Anything from 10K to 220K should probably do the same job.

Thank you! That is a huge help. Now I have to get to a radio shack and get the components I need. ^_^
 

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