First sorry about no responding to some threads I made, but this should have all the info you requested and hopefully answer all my questions.
Is there anyway to improve the layout on my breadboard (pictures below).
My main concern is my servo. I want to cut the power to it after it moves to it position. I can still hear noise coming from my servo (its holding my window blinds in a certain position) when the transistor is supposed to be closed.
Here are some specs:
Wall Wart: Rated: 9v 800aM - Actual: 10.5v
Voltage Regulator: Rated: 7805 5v - Actual: 4.98v
Through MOSFET: 4.98v when gate is open
1.99v when gate is (supposedly) closed
(terminology might be wrong but I think you know what i mean)
I get a max of 215mA when I try to stop the servo with my hand, but i have a stronger servo in my window blinds (5ft x 5ft, wood blinds) hard to get a reading up there
Here is a list of the items there that are more or less top to bottom:
If it works, it works. Or is it intended to be a museum display or something? (Why do you ask?)
I think you missed the point. Is there anything I could add or remove (or change the connections) to possibly fix the problems I'm having and are there any possible problems I might have with the current layout?
We don't know anything about your servo. Is it the kind that can hold its position (and hold you blinds up) when power is removed?
Yes it can hold the blinds in all the positions I have programmed without power (tested it).
Your image sharing website is TOO "helpful" and gives you a bunch of links to paste in, none of which work.
Well you are TOO nice every time i click them they show my pictures without me logging in or doing anything special. I don't know why its not working for you or possibly anyone else.
You know everyone here has always been very friendly and helpful. I don't see why it shouldn't always be that way.
Do the pictures still not load? Even on a small breadboard you really need the schematics?
Not that I don't want to write it but it'll probably take some time to figure out the program.
For my second question, the picture below describes what I'm talking about (I think this one will load). I don't see a resistor like that in schematics for MOSFETs (unless it's like a diode or something).
PS: The words "closed" and "open" are typically used in terms of conductivity when talking about electronics. A "closed" circuit conducts electricity, while an "open" circuit cannot pass current.
Do the pictures still not load? Even on a small breadboard you really need the schematics?
You may or may not need a drawing to build a simple circuit on a breadboard, but when asking for help or comments from others it's almost always required. Many circuit details are only evident from a well drawn schematic. A schematic is to a circuit what a program listing is to a software application.
Not that I don't want to write it but it'll probably take some time to figure out the program.
I have that problem also, but I do keep promising myself to install the free Eagle program and get started, soon.
For my second question, the picture below describes what I'm talking about (I think this one will load). I don't see a resistor like that in schematics for MOSFETs (unless it's like a diode or something).
It is a diode and it's not for the mosfet, it's for the motor to suppress transient spikes when the motor is switched off, it's a protection thing, the circuit will work without it but the mosfet could be damaged without it. Also what specific mosfet to use in that circuit is critical. Most N-channel mosfets require +10vdc on the gate to fully turn on, but the Arduino can only provide +5vdc output voltage. A LOGIC level mosfet is required for that circuit to work with an Arduino. An IRF510 is not a good choice, especially if the motor draws more then an amp or so. See the figure six graph in this data sheet: http://www.eecs.berkeley.edu/~boser/courses/40/labs/docs/IRF510.pdf .
Does something on the model number tell me if its a LOGIC level mosfet?
No, see the data sheet I linked in my prior post. It's a standard n channel mosfet requiring a full +10v gate to source voltage to be able to pass full rated current. Depending on the current requirements for your motor, you will most likely have problems using that mosfet, but if you already have it you can give it a try. Most likely the motor will not turn on, or if it does the mosfet may end up running very hot.
For a start you have drawn the symbol for a transistor in the place of Q2 but in the text you say it is a FET. If it is a FET and it will turn on with 5V then you don't really need the resistor. Just a 100R will do to protect the arduino pin from over current as the FET gate capacitor charges up.
Now you say that pin 10 has 2V coming out of it when you set it to be an output and write a logic zero to it? Is that right or are you doing something else, if so try that.
Then try and disconnect the FET gate and connect it to ground. Does the motor turn off? Is there still 2V coming from the output?
[edit]
The IRF510 will not turn on fully with 5V, this is the wrong FET to use in this application.
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ya, when I disconnect the gate it still reads 2v from the servo wires (didn't connect it to the ground will that make a big difference?)
It is a FET, and I have a 1k on the gate to the arduino pin
I assume it pin 10 is doing a output and write a logic zero. I have a class that controls the servo and I haven't opened the C file to look at it.
Sorry you just caught me before I was going to bed (other wise I would try some of your stuff)
I don't think 2v is much of an issue anymore. After fixing some of my code (another thread on his forum) I think the code was acting up (after I installed the FET, I didn't hear any noise coming from the servo till I screwd up the code).
I think the 2v isn't too much of an issue unless you think it is...?
when I disconnect the gate it still reads 2v from the servo wires
Oh I thought it was coming from the arduino. It is fine for you to read 2V from an input signal from the servo motor. T hats the one you show as being connected to pin 9.
(didn't connect it to the ground will that make a big difference?)
If it is the gate then yes it will. Ground will turn it off, floating will do just that, let it float and it will be in an indeterminate half on half off state.
When you connect it to the arduino you should read zero volts when a logic zero is on the output. Get rid of any classes and just put a zero on it. Same goes from
How do I connect it to ground during the normal operation of the transistor (I never see schematics layed out like that for NPN, the gate is just connected to a small voltage that turns on and off....my Pin 10 I have programmed to go from HIGH to LOW...does it need to connect to a ground to be completely off???)
What exactly is this is Logic zero I'm suppose to output from my pin? Is there a reference website?
I tried googling it and this misspelled thread is first thing to comes up ("Anyway to imrove my board?"...lol : )
What exactly is this is Logic zero I'm suppose to output from my pin?
It is a voltage below 0.8v
Is there a reference website?
How do I connect it to ground during the normal operation of the transistor
No this is a test not normal operation it is to see where the 2V you report seeing is coming from. Is it coming from the arduino or from what the arduino connects to. In any event the output arduino should be pulling this down to a zero, however a damaged arduino pin would not allow this, also a pin not set to be an output (they are inputs by default) would also behave the same.
Too much stuff about electronics feel like my head is going to explode sometimes. I think the board is fine now.
Just curious...I get about 4mV from Pin 10, but I get about 0.5V from Pin 9. One couldn't be damage could it?
One the servo I get 0.5V from the signal (Pin 9) using GRD of the 7805 or the . The positive lead of the servo to GRD on top (next to Pin 13) I get about 0.5V, but when I use the GRD connected to the 7805 I get about 2Vs. When I take out the MOSFET I get 5Vs (as expected). Is the 0.5V to 2V from different GRDs normal?
every time i click them they show my pictures without me logging in or doing anything special. I don't know why its not working for you or possibly anyone else.
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