[sen2009]

I am trying to make an ultrasonic fuel sensor work in trucks with 12V or 24V systems. While the performance of the sensor is quite admirable, it suffers hugely from voltage fluctuations in the vehicle's main system.

The sensor needs a steady input voltage of 14VDC to work consistently.

In trucks, the wiring works are mostly very very erratic with absolutely no concern for anything other than starting the truck, light up the headlights and blow the pressure horns. Above that, any truck more than 6 months old definitely has one or more Great Indian Jugaad signature in its wiring. Hence, leakage of current and massive fluctuations in short bursts are a certainty.

For example, in a 12V truck, the main line voltage can range between 10 to 16 Volts and for a 24V one, the range is 22V to 32 Volts.

So, I need a system which will do both step up or down (as required depending on Main line conditions), and supply a steady 14V DC even if input voltage is low, say 10V. The current requirement is about 1A or less.

I know of regulators which can do this job when input voltage higher than 14V by at least 5V. But, I can't find anything which will handle the low input voltage scenario as well.
I have tried a simple connection of LM7812. The vehicle I have installed this has a old battery which seldom supplies above 11.5 Volts. With the 7812, my supply to the sensor fluctuates between 10-11Volts. And, my sensor does not work.

What should I do to address this problem?
Please suggest if any readymade box is available for this.

[low_bass_makker]

Some thing like this will work great !!!!

DC-DC to USB Converter

[sen2009]

Originally Posted by low_bass_makker

Some thing like this will work great !!!!

DC-DC to USB Converter

That is an excellent suggestion. I need exactly this.
Only issue with this product is that it cost USD 60. So, for a single batch import of say 50 units will cost me about Rs. 5000/-.
My sensor costs about 7K, so this will affect the end user pricing a little bit.

Is there any cheaper alternatives available, Chinese or Indian make of the same thing maybe?

Can anyone suggest me a good search term for Ebay on this?

[greenhorn]

you either need a cheap DC to DC 12V convertor (doubtful). or start looking at building your own using a DC to DC convertor chip.
Or I suppose you should start hunting for a lower voltage sensor

[sirius1845]

why not try 7815 /7812 Voltage regulator chips. What is the current draw for the sensor?

[sen2009]

I am looking for just that. A cheap dc to dc converter which can handle both low and high input voltage. I couldn't find any, so I thought mod gurus will know about these stuff.

I am very much willing to make my own. I don't know nothing of electronics. I have a local tv repair guy who can solder. All I need is a simple circuit.

I have tried with 7812 in a 12V truck. The truck battery is kind of weak around 11.5 Volts. The 7812 output roams about 10.5 Vols. Never steady at any value. I think capacitors are needed to stabilize the voltage. But, how to connect them?

Any help is much appreciated.

[greenhorn]

Get a Buck Boost Voltage regulators here. At least something of this variety
Derive 12V From 8V to 15V Input - Maxim
Challenges in automotive power regulation
http://cds.linear.com/docs/Design%20Note/dn233f.pdf

I'm just curious why you're doing this. This is fairly serious electronics stuff, and your profile says your occupation is sales .

And I'm not an practicing engineer either, so take my advice at face value

[sen2009]

Originally Posted by greenhorn

Get a Buck Boost Voltage regulators here. At least something of this variety
Derive 12V From 8V to 15V Input - Maxim
Challenges in automotive power regulation
http://cds.linear.com/docs/Design%20Note/dn233f.pdf

I'm just curious why you're doing this. This is fairly serious electronics stuff, and your profile says your occupation is sales .

And I'm not an practicing engineer either, so take my advice at face value

I have a small fleet tracking business. I need this fuel sensor to work for my fleet owner cilents. Haven't gotten around to update the profile information.
I am going to check the links you have given right away..

[pranavt]

Try an NCV33063A. The rest is easy.

[sen2009]

Originally Posted by pranavt

Try an NCV33063A. The rest is easy.

Great find.
I am studying the datasheets for this part.
Is it commonly available in electronics part shops, like say Visha Electronics in Lamington Road?

Any other leads on where I could purchase this part?


And, can you please throw some light on the rest? I am a complete newbe in this. If you could point me to a circuit diagram then I could buy the stuff and get the soldering done.
I think this component cannot be used directly.

[greenhorn]

imo getting the inductor is going to be the harder part

[sen2009]

I will scout the local thane electronics market today and see if I can get something made with the NCV33063A.

Its a wonder that a readymade box is not available for this. I am sure voltage stabilizers have many automotive applications, especially for modders who like electronics.

[low_bass_makker]

UEI15-120-Q12P-C Murata Power Solutions | DC/DC converter,9-36Vin,12Vo 1.3A 15.6W | 689-5595 | Welcome to RS Online

The input range you require is quite large here which is 12-24 Volts which also varies from 9-28volts make the supply some what unique Or one can make two different system one with 10-14 volts and the other with 20-28 volts to further reduce cost make a universal one will be expensive !!!

[sen2009]

That is a wonderful site. I am browsing all options, and looks like I finally may get something here.

I want to kiss Low Bass Makker.

[sen2009]

Can someone please browse this site and tell me if there is anything I can use.
Online Shopping in Mumbai