Step down Buck the little board that can’t and might kill you.( WARNING FIRE HAZARD !!!!!!!!!)

DickCappels

Joined Aug 21, 2008
8,157
I guess that all depends on what you want to use it for. It looks like a neat little power module. Do you have any particular application in mind for it?

killivolt

Joined Jan 10, 2010
805
Just a window sensor, 500ma. Input voltage is 24vdc out 3vdc.

kv

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killivolt

Joined Jan 10, 2010
805
Do you think we have one here not shipped from china?

kv

MrSoftware

Joined Oct 29, 2013
2,015
If you can't find one on eBay or Amazon that is in the USA, try Spark Fun, Digikey or Mouser.

killivolt

Joined Jan 10, 2010
805
Do you think we have one here not shipped from china?

kv
Ships Aug 19 lol

kv

killivolt

Joined Jan 10, 2010
805
If you can't find one on eBay or Amazon that is in the USA, try Spark Fun, Digikey or Mouser.
I’ll try the same part or voltage rating.

Thank you,

kv

killivolt

Joined Jan 10, 2010
805
If you can't find one on eBay or Amazon that is in the USA, try Spark Fun, Digikey or Mouser.
Not seeing anything in that form or factor. Smaller the better, I will 3D print a section for the Buck just not sure of the part Mouser had some small ones I could incorporate that better than the one I‘m getting from Taiwan.

kv

MrSoftware

Joined Oct 29, 2013
2,015
Would 3.3V work? If yes, here's one option:

https://www.digikey.com/product-detail/en/cui-inc/VXO7803-500/102-4248-ND/7350287

Play with the filter here for more options:
https://www.digikey.com/products/en/power-supplies-board-mount/dc-dc-converters/922?k=DC+DC+CONVERTER+3V&k=&pkeyword=DC+DC+CONVERTER+3V&sv=0&pv16=202542&pv16=202544&pv16=228268&sf=1&FV=-8|922&quantity=&ColumnSort=0&page=1&stock=1&pageSize=25

There are adjustable modules out there too, you just have to get creative with the filters. Sometimes google will help you figure out the terms that you need to use for search engines on sites like digikey and mouser.

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killivolt

Joined Jan 10, 2010
805
I think it would be fine. I’m no researcher which is why I asked for some help. I would like it to be fixed I think this one is a much better match for what I’m trying to do.

Thank you for the help, I get so lost on those sites.

kv

Edit: Just so you know, I’m working to try and remove a battery on the sensor, I want solar on my house and want to integrate solar voltage from a central battery, My house is a beta test security system, but this is my application only. I just want to save my Customers money in the long run by implementing a solar battery which I’m yet to learn the exact operational voltage, I’m assuming I can draw as little as 12vdc or as much 36vcd or maybe other Voltages. I know 5vdc can only run a short distance so 24vdc or higher would work just fine in a home application. Depending on this part size I may not need to 3D print the cover, it might just fit in the enclosure.

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DickCappels

Joined Aug 21, 2008
8,157
That's not enough current to to get much benefit if any from a switching supply topology.

Gee, I don't know, at my regular distributor they are about U.S. 15¢ each.... L78L33ACZTR

killivolt

Joined Jan 10, 2010
805
That's not enough current to to get much benefit if any from a switching supply topology.

Gee, I don't know, at my regular distributor they are about U.S. 15¢ each.... L78L33ACZTR
At 24vdc would be ideal. But, it’s rated at .1 when I need 5mA it appears to be to small. What am I missing.

MrSoftware

Joined Oct 29, 2013
2,015
What window sensor are you using, 5mA is an enormous current for a window sensor. Are they wireless? Run your numbers on paper to see if the extra expense makes financial sense. For example, I've got wireless Ademco window sensors (industry standard, less than $15/ea retail) in my house and the batteries (CR123A) last years, literally years. I installed the sensors almost 4 years ago and haven't replaced one battery yet. Even at retail prices the batteries are under$2/ea. So even if your solar parts work perfectly, I suspect it will be a very long time before you make up the extra expense, if at all.

killivolt

Joined Jan 10, 2010
805
What window sensor are you using, 5mA is an enormous current for a window sensor. Are they wireless? Run your numbers on paper to see if the extra expense makes financial sense. For example, I've got wireless Ademco window sensors (industry standard, less than $15/ea retail) in my house and the batteries (CR123A) last years, literally years. I installed the sensors almost 4 years ago and haven't replaced one battery yet. Even at retail prices the batteries are under$2/ea. So even if your solar parts work perfectly, I suspect it will be a very long time before you make up the extra expense, if at all.
Yes wireless 350Mz. I have older folks that don’t want to replace batteries we try not to send a Tech for things like that and right now I’m getting at least 3 calls a day for suck things.

kv

High Traffic areas such as businesses use up a 3vdc CR2032 in a couple weeks with our system.

DickCappels

Joined Aug 21, 2008
8,157
At 24vdc would be ideal. But, it’s rated at .1 when I need 5mA it appears to be to small. What am I missing?
To keep from confusing each other, I will stick to milliamps and hope you will also.

The L78L33 can supply up to 100 milliamps (0.1 amps) but it will not supply more current than the load requires at the regulator's normal output voltage. Your window switch apparently requires 5 milliamps or 5% of the regulators 100 ma capability.

The quiescent current for this regulator is about 5 milliamps, meaning that it will draw about 5 ma on its input even if there is no load on the output.

For battery powered applications in which every milliamp is precious I prefer low power low drop-out regulators like the MCP1702 series which are more expensive but have a quiescent current of 2 microamps.

MrSoftware

Joined Oct 29, 2013
2,015
Yes wireless 350Mz. I have older folks that don’t want to replace batteries we try not to send a Tech for things like that and right now I’m getting at least 3 calls a day for suck things.

kv

High Traffic areas such as businesses use up a 3vdc CR2032 in a couple weeks with our system.
I understand your economic point. That said; a CR2032 is itsy bitsy, about 220mAh. A CR123A is about 1500mAh capacity. In liu of your ultimate solution of plugging it in, switching to a similar sensor that uses CR123A should in theory cut your calls by a factor of 6.

killivolt

Joined Jan 10, 2010
805
To keep from confusing each other, I will stick to milliamps and hope you will also.

The L78L33 can supply up to 100 milliamps (0.1 amps) but it will not supply more current than the load requires at the regulator's normal output voltage. Your window switch apparently requires 5 milliamps or 5% of the regulators 100 ma capability.

The quiescent current for this regulator is about 5 milliamps, meaning that it will draw about 5 ma on its input even if there is no load on the output.

For battery powered applications in which every milliamp is precious I prefer low power low drop-out regulators like the MCP1702 series which are more expensive but have a quiescent current of 2 microamps.
Been so long since I talked amps vs miliamps I didn’t realize thx for the correction.

I understand your economic point. That said; a CR2032 is itsy bitsy, about 220mAh. A CR123A is about 1500mAh capacity. In liu of your ultimate solution of plugging it in, switching to a similar sensor that uses CR123A should in theory cut your calls by a factor of 6.
The company I work for is Vivint and they also have Solar so it’s my way of making it compatible. I have no idea if they’ll want the idea or not, but I’m installing Solar on my house and will try and deploy this in my home regardless.

I’m getting old to you know lol

kv

killivolt

Joined Jan 10, 2010
805
I have a 12v gel cell battery, I will integrate the sensor when I get the Buck on the 19th. After that I will try the other options in the thread and report back. They install the security system today. All working properly at this point until I try my optional solar experiment.

kv

killivolt

Joined Jan 10, 2010
805
Got my Buck from china today, going to do a little cov19 cleaning with gloves.

kv

Edit: Decided to just let it sit in bowl then charge my 12v gel cell and print the new housing. I’ll mock a door window installation and test it over time, recording any events If any.

kv

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