Help With Ophir Head and Panel Meter-1 Battery

Nocturnal · Nov 8, 2011

hey guys, I have brought an Ophir 20C-A head and digital panel meter, but I read I cannot hook them up to one battery in parallel? Could someone please show me how I could run these two components off the same battery.

Cheers,
Chris

:thanks:

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Bluefan · Nov 8, 2011

The Ophir head needs a symmetrical power supply, you could split the voltage of the battery or use a DC-DC converter. Keep in mind that the output voltage of the head can only go up to the power supply voltage minus 2 volts.

Nocturnal · Nov 8, 2011

Thanks,
Can you please show me a schematic or picture. I really don't want to stuff up the thermopile. I have lm7805's and lm7806's. and want to power Both the Ophir head and dpm off the same battery. Thanks.

Chris

Flaminpyro · Nov 8, 2011

Here is a diagram for you hope it helps

Pay attention the the voltage and the polarity.

Here is the sheet that tells what is what.

And here is a wiring diagram.

rhd · Nov 8, 2011

I'm experimenting with the concept of using a 7805 and a 7810 to create a +5 and +10 output, such that the +5 could be used as the virtual ground, the +10 as (essentially) the +5 for the Ophir, and the true GND as the -5 for the Ophir.

I don't know if this will work as theorized, but I'll let you know how it works out this weekend. This would make it relatively simple to use one power source for all of the above, with minimal components.

lasersbee · Nov 8, 2011

Flaminpyro said:
Here is a diagram for you hope it helps
Pay attention the the voltage and the polarity.

And here is a wiring diagram.

As I've already stated in another Thgread....the junction of the
brown wire and the gray wire needs to be tied together in that
drawing or the head won't work...

Nocturnal said:
hey guys, I have brought an Ophir 20C-A head and digital panel meter, but I read I cannot hook them up to one battery in parallel? Could someone please show me how I could run these two components off the same battery.

Cheers,
Chris

If you are intent to run both the OPHIR Head and a DPM from
a single supply you WILL need a +/- DC/DC converter fro the
Head +/- split supply and a positive voltage regulator for the
voltage that your DPM requires....

BTW a 9Volt batter will not run very long powering the DC/DC
converter.... the OPHIR Head and the DPM....

rhd said:
I'm experimenting with the concept of using a 7805 and a 7810 to create a +5 and +10 output, such that the +5 could be used as the virtual ground, the +10 as (essentially) the +5 for the Ophir, and the true GND as the -5 for the Ophir.

I don't know if this will work as theorized, but I'll let you know how it works out this weekend. This would make it relatively simple to use one power source for all of the above, with minimal components.

Sorry... I can't see it working due to common grounds.....
A Schematic of your setup would make an evaluation
much clearer...

The OPHIR head requires more than 5volts IIRC....

Jerry

rhd · Nov 8, 2011

This will make Jerry really happy

This is not a schematic, but it shows the basic concept. I don't know that it will work either. However, 5V +/- is enough for an Ophir if you check out the datasheet.

jib77 · Nov 8, 2011

The following circuit splits any voltage input in half ... i.e. a 12V wall wart will give you +6 and -6VDC. You can still use two 9V batteries for +9/-9V, but with a simple hookup. To use a panel meter on the same supply, you simply hook up a 7805 or LM1117/5V to the +V and virtual ground and run that to the meter.

Schematic here:
http://laserpointerforums.com/f67/driver-circuit-thread-65149.html#post935277

lasersbee · Nov 8, 2011

rhd said:
This will make Jerry really happy

This is not a schematic, but it shows the basic concept. I don't know that it will work either. However, 5V +/- is enough for an Ophir if you check out the datasheet.

Thanks... that will help the members that were not aware...

BTW... It has nothing to do with making me happy...
It has to do with the proper way of showing a connection
on that drawing... Two different color traces are not normally
connected together unless specified.

As to your basic concept circuit you will see clearly that it
will not work once you draw in the Ground connections
required by the Positive regulators...

All I see is from top to bottom... [+12] [+6] [Ground]

jib77 said:
The following circuit splits any voltage input in half ... i.e. a 12V wall wart will give you +6 and -6VDC. You can still use two 9V batteries for +9/-9V, but with a simple hookup. To use a panel meter on the same supply, you simply hook up a 7805 or LM1117/5V to the +V and virtual ground and run that to the meter.

Schematic here:
http://laserpointerforums.com/f67/driver-circuit-thread-65149.html#post935277

You would need a Low Drop Out 5V Regulator if you are
supplying only 6V to it. The 7805 would never regulate
the 6Volts from your PCB to 5Volts properly... if using
a 12volt wall wart

Increasing the the input voltage to your PCB to above
16Volts would allow you to use the 7805..

BTW... I would supply a regulated input voltage to your
circuit just to keep the voltages to the OPHIR head stable.

Jerry

rhd · Nov 8, 2011

lasersbee said:
As to your basic concept circuit you will see clearly that it
will not work once you draw in the Ground connections
required by the Positive regulators...

All I see is from top to bottom... [+12] [+6] [Ground]

Yep, that's what you'd have. The question is whether the +6V can function as a virtual ground, with the actual ground functioning as a -6V and the +12 functioning as a +6V relative to it.

More like this:

But - like I said, just testing it out. I don't know whether the concept is solid. It sounds like it might not be. That's cool. It would have been a simpler approach had it worked.

lasersbee said:
You would need a Low Drop Out 5V Regulator if you are
supplying only 6V to it. The 7805 would never regulate
the 6Volts from your PCB to 5Volts properly... if using
a 12volt wall wart

You could probably just hook the 7805 to the source +12V and GND.

Cyparagon · Nov 8, 2011

Good plan. I see no reason why that wouldn't work fine.

lasersbee · Nov 8, 2011

rhd said:
This is not a schematic, but it shows the basic concept. I don't know that it will work either. However, 5V +/- is enough for an Ophir if you check out the datasheet.

Hey RHD....

I'm impressed...
I just built this circuit and it does seem to work...

The only problem is that between the Ground and +6V
in your drawing above there is no regulation and the
current supplied is very low...

Here are some readings I just took dropping in different
resistors I had laying around..

Res........ mA........Voltage

~ .......... 0 .......... 6.33
10K........ 0.6........ 6.34
4K7........ 1.4........ 6.60
3K3........ 2.4........ 7.59
2K2........ 3.3........ 7.12
1K5........ 4.1........ 6.18
1K0........ 5.1........ 4.96
330........ 7.4........ 2.37

Jerry

jib77 · Nov 9, 2011

You would need a Low Drop Out 5V Regulator if you are
supplying only 6V to it. The 7805 would never regulate
the 6Volts from your PCB to 5Volts properly... if using
a 12volt wall wart

Increasing the the input voltage to your PCB to above
16Volts would allow you to use the 7805..

BTW... I would supply a regulated input voltage to your
circuit just to keep the voltages to the OPHIR head stable.

Jerry

Yup ... I used a fixed 5V LM1117 in my build and it works great with a switchmode regulated 12V wall wart. I scoped the output and there was minimal ripple on the +6V rail (~25mV P-P) and almost dead flat on the virtual ground.

Nocturnal · Nov 9, 2011

Thanks for the responses. I'm going with the jib77 circuit. pm sent

Nocturnal · Dec 12, 2011

hey guys, I hope this isn't considered a necropost :?
Anyway I was wondering if you guys could please check this drawing.
I just need to check:
Whether it will even work!
If 'piggybacking' the dpm power off the 9v has any affect on the accuracy of the ophir head,
and the polarity and value of the capacitors

This is the dc/dc converter:XP POWER|IQ0509S|DC/DC CONVERTER, SEMI REG, , DUAL | element14 Australia
Datasheet: http://datasheet.octopart.com/IQ0509S-XP-Power-datasheet-10025710.pdf

Thanks

lasersbee · Dec 12, 2011

Nocturnal said:
hey guys, I hope this isn't considered a necropost :?
Anyway I was wondering if you guys could please check this drawing.
I just need to check:
Whether it will even work!
If 'piggybacking' the dpm power off the 9v has any affect on the accuracy of the ophir head,
and the polarity and value of the capacitors

This is the dc/dc converter:XP POWER|IQ0509S|DC/DC CONVERTER, SEMI REG, , DUAL | element14 Australia
Datasheet: http://datasheet.octopart.com/IQ0509S-XP-Power-datasheet-10025710.pdf

Thanks

1) We don't know the value or voltage of your Caps

2) It is better to tap off the battery than the DC/DC Converter
assuming that your DPM has a 9Volt supply requirement.

3) The capacitors on the output of your DC/DC converter are
connected in reverse.

Jerry

Help With Ophir Head and Panel Meter-1 Battery

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