Raspberry Pi Forums

boyoh

This 2 speed fan controll might be what you want Using just the one GPIO output Select the transistor to suit motor full load current Select resistor to give voltage drop for Fan speed 1. GPIO at active high output .Transistor ON Full speed 2. GPIO at active Low output Transistor OFF half speed ?

boyoh

The opto isolator will isolate the Fan power circuit from the the Pi 3.3v GPIO pins Select the fan switching transistor To suit the fan load current. You can change the Pi resister Values, but don't take more then 16ma from the Pi GPIO output pin

boyoh

I'm tinkering with a stepper motor driven by an Easydriver controller and all is working well. By default the controller is set to 1/8 step but this can be overridden by tying a couple of the pins to ground to set 1/4, 1/2 or full step and I figure using a couple of transistors is the easiest way t...

boyoh

Why? Think about the crystal sets you used to make when you were a kid. They were able to tune a local AM radio signal and provide enough power to drive a crystal earphone. If the power consumption of a pi could be reduced to these levels then a pi could be run off a simple coil and capacitor and a...

boyoh

I suggest if you are using different voltages between your Pi and your breadboard projects, you inter face using Opto isolators This will give you total isolation, between Different voltages, and protect you Pi Inputs and outputs 3.3v & 5v The PI and Gertduino are already using "different voltages"...

boyoh

I suggest if you are using different voltages between your Pi and your breadboard projects, you inter face using Opto isolators This will give you total isolation, between Different voltages, and protect you Pi Inputs and outputs 3.3v & 5v The PI and Gertduino are already using "different voltages"...

boyoh

When you have completed your project DO NOT TEST IT IN A HOSTILE ENVIROMENT Submitt it to the Health and safety first It is nice to know the theory, but you have to know The practical side as well

boyoh

Nice to hear some one talk about Crystal sets must be some one around my age I made my first Crystal set in 1945 when I was 14. Bought the Cats whisker diode from Curry's Wound a coil of Double Cotton coverd wire. Used a pair of BBC head phones I was given. Yes it would be nice to have a very low po...

boyoh

I suggest if you are using different voltages between your Pi and your breadboard projects, you inter face using Opto isolators This will give you total isolation, between Different voltages, and protect you Pi Inputs and outputs 3.3v & 5v

boyoh

Headless didn't fix it; I also tried completely turning off my desktop (monitors included), to no avail. Also tried multiple outlets in this room. Also tried (at my brother's suggestion) turning on the microwave to see if anything changed (nothing changed). This is a pretty high quality power adapt...

boyoh

One cause of electrical noise in a domestic Instlation is refrigerators switching on & off. Olso fluorescent lights ballast units are highly Inductive, Filtering out noise in a domestic Insalation is a trial and error job, Have you tried a anti surge,adapter might be Worth a try.

boyoh

The age it self does not matter it simply depends on how much support they have to do it. I've use the Raspberry Pi with a 5 year old without problems, but she needed a lot of help and guidance to see what it was all about. It helps if they are able to read, but being interested and wanting to list...

boyoh

Two Million Pi x Two Million Problems
That will keep the Forum busy

boyoh

Well you live in the land of the Silicon Chip. I thought there was a Radio Shack on every street corner They were called Tandys in the UK, They are all closed now, but they Still trade on line and stock a lot of Pi components, go on line and see if they Trade in the USA BoyOh

boyoh

The trouble with some power adapters Is not having good smoothing capacitors The Uk 50 hertz when full wave rectification Is don you get 100 hertz ripple. If not filtered Out can show up on some sensitive Circuits, Then there is noise witch Needs to be filtered out

boyoh

hmm... i dont understand why it is connected to the 3.3 v pin on the raspberry just to take a example with a nfc reader (uses a l2c interface) i was more thinking about somthing in this style (sorry for the terreble scheme) A expiation of your project will help a lot There are a few types of NFC re...

boyoh

An example of switching a 12v relay From a Pi GPIO 3.3v output pin Using a Opto Isolator to isolate the Pi Low volts from the breadboard high volts. There are other ways , But I think this Is A very simple way, and safe.

boyoh

No the opto isolator is not the the feed to The Pi 5v this is from a separate adapter Or battery The opto isolator is used between the Pi GPIO 3.3v out put pin and the bread board Projects, It will give totol isolation between The Pi and bread board. Pi O/P Pi GPIO------( R )------( I/R led )------0...

boyoh

Yes a separate variable power supply feeding the bread board Is A very good idea, That is what I use,it is very easy to use Transisters and opto isolators to separate the Pi low voltage From the bread board project voltages feeding back to the Pi. BoyOh

boyoh

Use the correct voltage the Pi Was designed for. Your lovely poetic advice, Does seem a little misplaced In a section for users advanced. When the Pi goes up in a balloon There's a risk it won't safely return; It isn't a priceless heirloom. That is a very honest answered, and not misplaced In the a...

boyoh

Use the correct voltage the Pi Was designed for. Your lovely poetic advice, Does seem a little misplaced In a section for users advanced. When the Pi goes up in a balloon There's a risk it won't safely return; It isn't a priceless heirloom. As a advanced user you don't seem Very confident of your p...

boyoh

jojopi wrote:
boyoh wrote: Use the correct voltage the Pi
Was designed for.
Your lovely poetic advice,
Does seem a little misplaced
In a section for users advanced.

When the Pi goes up in a balloon
There's a risk it won't safely return;
It isn't a priceless heirloom.

boyoh

If you are a novice on electronics, Don't take any advice on using A soldering Iron to the Pi board Even a skilled technician would Would have to take care doing It' Use the correct voltage the Pi Was designed for.

boyoh

[quote="boyoh"]You could monitor the battery level with a circuit That will tell when a critical level is retched You could use a Zener Diode switching a Opto isolator then the opto isolator transistor taking the input of the Pi GPIO input pin to a Active High Or active Low depending on the Pull up ...

boyoh

I think what we are trying to do, is use a sledge hammer To crack a pea nut. The more components we use to Check the battery voltage level, will use more current This will only compound the problem by discharging The battery faster.

Search found 1466 matches

Re: Motor speedcontrolling with transistor (PWMorTransistor-

Re: Fan for Raspberry Pi

Re: Transistor - resistor calculation

Re: Request for ultra low power pi

Re: Power Supply

Re: Power Supply

Re: Help Please

Re: Request for ultra low power pi

Re: Power Supply

Re: Ripple problem with camera

Re: Ripple problem with camera

Re: new to raspberry pi - ages of users

Re: 2 Million Pi sold, how many..

Re: Where do you buy your components

Re: Ripple problem with camera

Re: Seperatly powering a breadboard

Re: Seperatly powering a breadboard

Re: Seperatly powering a breadboard

Re: Seperatly powering a breadboard

Re: Running Raspberry on 3.3 V

Re: Running Raspberry on 3.3 V

Re: Running Raspberry on 3.3 V

Re: Running Raspberry on 3.3 V

Re: Simple A to D to monitor voltage

Re: Simple A to D to monitor voltage