You live in the land of the Silicone Chip.
And you want to know were to buy
LEDs Resisters and electronic
Components, they are all on your
Doorstep " RADIO SHACK"
It might be better if you draw a diagram of your project.
It will give some idea of what your circuit values want to be
Then someone will post the values for you,
Don't use a LED to dissipate the " Fly back Current "generated By the motor when it stops. The voltage generated can be A lot higher than the driving voltage,and can damage the the control electronics. Use a diode to circulate it fast and quick back through the motor winding
Am I getting your problem right, you want to control your Pi by Switching on and off your Pi By switching your monitor on and off Vie the HDMI cable, I might be wrong , I think your Pi must be Booted up first before it can respond to any signal from your monitor. I might under stand how you can shut...
One option for your fibre optics, look round
A hardware store you might pick up a cheap
Fibre optic Christmas tree withe the rotating
disc and lamp, use the Pi to control the disc and lamp
That won't work. I've redrawn that: 2leds1.gif As you can see, the 3v3 from the GPIO has to be split between the transistor b-e junction (0.6v), the two LEDs (1.7v each) and the resistor. Unfortunately 1.7+1.7+0.6 = 4v, more than the 3.3v the GPIO gives out, so there'll be nothing across the resist...
Transister 2n2222 ( npn ) GPIO C----------9V+ 3.3v+------- B 1.7v 1.7v E ----- LED-------LED----RESISTER----OV- ( 20ma ) 280ohme ( Copy for other 2 LED,s Total load for both Appox 50ma Including base currents 9v+-- 1.7 + 1.7 = 5.6v 5,6v ------ = 280 ohms 0.02ma (20ma) Link ov-Pi & 0v Battery as Comm...
Try using a Opto isolator You will have total insolation
Between the two power supply's the Pi and relay 12v
The Opto isolator will act as a solid state switch
My advice is buy a breadboard and a power supply A few transistors some LEDs a few diodes some resisters A multi meter , A book on building electronic circuits on A breadboard. Then you will understand all the Technical jargon you are given, Best to start from the bottom And get to grips with OHMS LAW
If you use the adapter with the two USB outputs
You will be sharing the 1.5A with both USB ports.
You will afto calculate what load you will using
from each port
The high voltage is nothing to do with the Pi soft ware, It is the power supply, Are you checking the voltage on T1 & T2 on the PI. There are two tests to carrie out OFF LOAD & ON LOAD. Give the Pi some output load then test the voltage. Also check the 3.3v at the same time, If the 3.3v is well out,...
Do you switch off and switch on the Pi from the power adapter. This can sometimes create a inductive spike from the adapter And corrupt the card. If the output lead is not filtered with a ceramic Clamp Try unplugging the micro USB to switch the Pi on and off Give it a try, no harm don
Hi, I've got my RPI rigged up with a toggle button connected to GPIO. I'm using the callback function to do some stuff when the button is pushed. Which is all working just fine except when I run my espresso grinder which is plugged into the same outlet, this triggers the GPIO falling condition some...
Hi, I've got my RPI rigged up with a toggle button connected to GPIO. I'm using the callback function to do some stuff when the button is pushed. Which is all working just fine except when I run my espresso grinder which is plugged into the same outlet, this triggers the GPIO falling condition some...
First things first, Kill the interference before it get to the PI. !. Don't grind coffee while using the Pi 2. Plug the grinder in to a filtered power socket. 3, As your power adapter for the Pi got a ceramic filter on the out put low voltage to the Pi, if not you can buy one to clip on. 4. It's bes...
Thanks, I'll check this out ! Now I have another problem. I'll order my rpi with some basics electronics stuffs, but there is no electronic store in my city, so I'll have to order all another stuff for my project on internet, and that's a problem because if I forgot one thing, I'll have to wait few...
Thanks, I'll check this out ! Now I have another problem. I'll order my rpi with some basics electronics stuffs, but there is no electronic store in my city, so I'll have to order all another stuff for my project on internet, and that's a problem because if I forgot one thing, I'll have to wait few...
My advice is learn some Electronics projects building On a Breadboard first, using batteries or a power supply Then control them with the Pi out puts. Get a projects building book, and a Breadboard From Maplins Electronic Project Building For Beginners Product Code WN72P
.., also you are bypassing the electrolytic capacitor on the Pi input power supply. [Quibble]Actually, no. C6 is after the poly-fuse, directly on the 5v rail, so it's always in circuit (unless you've knocked it off)[/quibble] Yes you are correct, the the voltage is on the capacitor. But after the c...
My advice is stick to feeding the Pi power using a good micro USB 2000ma (2A) power adapter Using back powering, you are relying on the hubs power supply being well filtered for DC ripple, also you are bypassing The electrolytic capacitor on the Pi input power supply. The capacitor will recover any ...
I agree with you the Pi as a very high input impedance, But the potential devider calculation is still the same What ever current you are taking off it. I think a ratio of 10 to 1 is quit good, this allows backup current from the devider.. With out sufficient backup current the the input signal coul...