What is the simplest, cheapest, off-the-shelf component that will allow me to output 0-100% of a separate input?
For example, If I have a 12v input going into , and I send 2.5v to it (50% of 5v) from the arduino's analog out, it will output 6v (50% of 12v). Is such a part commonly available off-the-shelf for low amp applications?
I initially thought a boost converter would be right, but for some reason those things seem to be made to maintain a specified voltage, say 6v, as long as the input is lower, and above some minimum. The key problem is that I want the output to change as the input changes, as a function of the input.
Think cheap, small, low-amp, arduino-controlled power supply
I have another idea. If I took regulated 5v from some other source, and added that to the arduino's analog out? I would need some sort of protection (diodes) so that that additional voltage doesn't feed back into the arduino though. So basically, the analog out of the arduino would now output 5v-10v, since 5v is being added to it, instead of 0-5v. Does that make sense? If so, the next question would be, do I just need a diode on the analog out, or also one on the ground line too?
For the first post in this thread, you would just take the problem for what it is. Just like you would on a test for an electronics course. "Name a device that can map a lower voltage to a higher voltage. Example: 0-5v input to 0-12v output"
For the other post I made in this thread, process is the same. You would just think of it like a test question, "If you added voltage to an analog output to boost its voltage, what would need to be done to protect that circuit from damage?"
I get questions that I would prefer more context on all the time from customers. You just answer the best you can with the information provided and then ask for more info at the end.
Did you understand the part that most Arduinos DON't have an analogue output.
They have digital outputs. Switching between 0volt and 5volt.
Nothing in between.
There are several ways to convert PWM into a voltage.
That could well be 0-12volt, or 5-7volt.
You will need external parts for that.
Parts will depend on what you want to do.
Leo..
BillHo:
How you apply the voltage output will affect the design of the circuit. what is current need for the output voltage?
you can get 0-5v input to 0-12v output by using Op Amp circuit but will be low current.
Yep. Low current is fine. I'm just trying to make a stock power-chair controller board think that the joystick is still there even though I've replaced it with with outputs from an arduino.
MorganS:
Voltage doubler, opamp, power amp... the options are endless.
How much current?
How much voltage?
What frequency?
What accuracy?
If you can answer those, then perhaps there might be a suggestion of a specific component for your specific application.
How much current? < 100mA
How much voltage? range of 4.5v-7v
What frequency? flat DC output, 5v PWM input
What accuracy? +-0.05v
Imagine you cut out a 2d joystick from a circuit. The joystick uses a hall-effect sensor. The inputs are:
Red: 11.88v steady
green: 6v steady
blue: (left/right axis) 4.6v-6.95v, depending on joystick position - slight, static pulse
yellow: (forward/reverse axis) 4.6v-6.95v, depending on joystick position - slight, static pulse
black: ground
You want to make the circuit still think the joystick is there, but instead an arduino is translating PWM from an RC receiver into the input expected by the board
Do you know if there's any current flowing through the signal lines? If not, you could generate analog voltage with RC filter, and use that as one end of a voltage divider, and the 12v as the other side. If so, actually, you could do the same thing, but just buffer it with an opamp.
You can do things like that with opamps and resistors and an RC filtered PWM output.
Alternately, you might generate the voltage with a DAC, or using a high voltage digital potentiometer like the MCP41HVxx series (both of these would also need an opamp to buffer the output if it needs to handle more than a miniscule amount of current)
Please post a picture of that device, sounds very interresting.
David82:
slight, static pulse
Please post an oscilloscope measurement of that too.
All pulses I know are, pulses because they are not static,
so this seems to be a new concept, I was not aware of.
And 'slight' pulses could be very hard to detect, but much more facile to simulate,
dependig on the meaning of slight in that context.
