Show Posts
Pages: 1 ... 3 4 [5] 6 7 ... 23
61  Using Arduino / Project Guidance / 2 loads not working together on the same battery on: January 15, 2013, 07:25:30 pm
One 12v car battery powers 2 loads. One load is 3.5A and the other is 100mA. The 100mA load is always on and when the 3.5A load gets switched on, scope readings show the amp draw momentarily dropping to half or less and voltage dropping from 12v to about 9.5v on the 100mA load. How can I maintain steady, smooth voltage and current to the low amp load during the brief time that the much larger load is energized? Would I need to use a large inductor or large cap to help momentarily sustain the 100mA current and voltage during this time?
62  Using Arduino / General Electronics / Re: A few simple questions about inductors.. on: January 15, 2013, 07:13:28 pm
I have an 85mA load (analog camera) that shares a power supply with a 4A load that is occasionally switched on. Even if the power supply is a car battery, the amp draw and voltage to the camera gets sucked away briefly when the 4A load is switched on causing the camera to flicker. I was thinking a 125mA, 10H inductor would maintain the current and voltage to the camera (or at least make the transitions smoother). Is this the right thinking or should I be looking at using a large cap instead?
63  Using Arduino / General Electronics / A few simple questions about inductors.. on: January 15, 2013, 04:35:15 pm
Using the image below as a reference,
1. What would the two graphs look like if switched from a, to b, then back to a (instead of c)?
2. Why is a resistor used in the circuit? Alternatively, what would the graph look like without it?
3. Could the first voltage spike be taken care of with a voltage regulator and the second with a diode, or would both be handled by the regulator?
64  Using Arduino / Project Guidance / Re: Video flicker problem with lots of scope data on: January 15, 2013, 04:21:27 pm
I think you are wasting time on that approach.
It's either going to need to be a large cap or an inductor. Something needs to be there to maintain voltage and current to the camera during the brief moment when the 4A load is sucking it all away. It's ok if voltage to the camera drops, as long as it's smooth and gradual. Which component would fix it?
65  Using Arduino / Project Guidance / Re: Video flicker problem with lots of scope data on: January 14, 2013, 09:48:55 pm
The current going to the camera drops from a steady 85mA to about half, and sometimes zero, briefly, when the load is engaged.
1. Does that support the theory that the switching of the 4A load is momentarily diverting all of the current toward itself?
2. Does the lack of needed current to the camera explain why the voltage to the camera also drops?
3. If an inductor is used to maintain current, will it also maintain the voltage (assuming a diode and voltage regulator are used to filter out the voltage spikes)?
66  Using Arduino / Project Guidance / Re: Video flicker problem with lots of scope data on: January 14, 2013, 08:14:45 pm
nope, but I've tried that on a few different occasions with the same results.
67  Using Arduino / Project Guidance / Re: Video flicker problem with lots of scope data on: January 14, 2013, 07:33:03 pm
The load and camera are on separate + leads and share the same ground wire. The switch for the load is actually near the power supply and two separate wires power the camera and load.
68  Using Arduino / Project Guidance / Re: Is there such a thing as a 1 amp, DC circuit breaker? on: January 14, 2013, 07:31:15 pm
yea, that's them. that wasn't your original link. Anyway, those are just online and are, of course, going to be over priced since it's radioshack.
http://www.digikey.com/catalog/en/partgroup/polyfuse-60r-series/10877
69  Using Arduino / Project Guidance / Re: Is there such a thing as a 1 amp, DC circuit breaker? on: January 14, 2013, 07:17:03 pm
I appreciate the help but that's obviously not it. I did finally find the answer though for anyone else that finds this thread. You use what is called a polyfuse (aka, polyswitch). They are perfect. They are cheap and open the circuit when they get hot while closing the circuit when they cool down. Perfect.
http://en.wikipedia.org/wiki/Resettable_fuse
70  Using Arduino / Project Guidance / Is there such a thing as a 1 amp, DC circuit breaker? on: January 14, 2013, 07:00:42 pm
I've tried googling it but found nothing that meets the requirement. I have an autonomous robot that uses servos. On rare occasion, it gets stuck in some weird position that will cause the servo to burn up. If I had a circuit breaker or even a low amp automotive fuse, I could save myself some money.
71  Using Arduino / Project Guidance / Re: Video flicker problem with lots of scope data on: January 14, 2013, 06:17:39 pm
The camera draws 85mA. I have a 125mA, 10H inductor coming in the mail. The idea is that when the current gets sucked away by the 4A load, the inductor will be there to maintain current to the camera and hopefully prevent the momentary loss of video. If that doesn't work, I guess I can try a much larger 12v capacitor

This is an image of how an inductor can smooth out current draw.


It seems that the camera can run on a range of voltages but it just doesn't like sudden changes in voltage.
72  Using Arduino / Project Guidance / Re: Video flicker problem with lots of scope data on: January 14, 2013, 03:56:49 pm
If you can't help solve it, then there is no point in nagging about it. Please stop trying to hijack my thread.
73  Using Arduino / Project Guidance / Re: Video flicker problem with lots of scope data on: January 14, 2013, 12:05:29 pm
Is the following analogy correct?:

If thought of like a Y connection in a water pipe, when the the high amp load is turned on all of the water (amperage) flows into it temporarily depriving the camera of current and causing the brief loss of video. Once the motor's on, the current flow stabilizes and the video is clear again while the motor is powered. Is that what's happening? if so, how do you make sure the camera will always have the current and voltage it needs to operate smoothly? Use an inductor?
74  Using Arduino / Project Guidance / Re: Video flicker problem with lots of scope data on: January 14, 2013, 10:27:18 am
I'm trying to provide the information necessary for someone experienced enough to actually explain why the problem exists and exactly, with certainty, what will solve it.
75  Using Arduino / Project Guidance / Re: Video flicker problem with lots of scope data on: January 14, 2013, 07:41:27 am
8ft like it says in the wiring illustration and again a few replies back.
Pages: 1 ... 3 4 [5] 6 7 ... 23