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by RaspISteve
Thu Dec 03, 2015 11:23 pm
Forum: Automation, sensing and robotics
Topic: Terminating WiringPI
Replies: 5
Views: 1141

Terminating WiringPI

Guys, I'm sure I've read it somewhere but now cannot find out what I should do once my program has finished with WiringPi. Being a bit old fashioned I expect to give all the GPIO thingys back or make them safe when I've finished with them. As I'm also using the interrupt extentions I also feel these...
by RaspISteve
Fri Nov 27, 2015 9:28 pm
Forum: Automation, sensing and robotics
Topic: how to replace a switch with relay in a 2 switch circuit
Replies: 4
Views: 1372

Re: how to replace a switch with relay in a 2 switch circuit

Tinker, If you can come up with a change-over relay that swaps L1a -> L1b and L2a -> L2b for L1a -> L2b and L2a -> L1b you can then have any number of Pi's capable to changing the current ON/OFF state of the lamp. You can also buy those cross-over switches from the bigger distributors. If you think ...
by RaspISteve
Fri Nov 27, 2015 2:20 pm
Forum: The MagPi
Topic: Don't Buy Magpi 40 from eBay
Replies: 17
Views: 4512

Don't Buy Magpi 40 from eBay

Guys, Just looking at the comments from folk trying to buy a (their regular??) Magpi from the likes of WH Smith (UK News Agent). Seems the first comes, first served are buying up all (mulitple) copies in one go (reports of this in the comments). One comment reports seeing issue 40 on eBay for 35 qui...
by RaspISteve
Thu Nov 26, 2015 6:31 pm
Forum: Advanced users
Topic: Remove USBs
Replies: 10
Views: 1238

Re: Remove USBs

I/we always worked on the basis of a modern multi-layer board must be saved at all costs including the total (and careful) destruction of whatever you needed to remove. Would always VERY CAREFULLY cut away the target component as high off the board as possible to avoid cooking or peeling off the cop...
by RaspISteve
Wed Sep 02, 2015 8:53 pm
Forum: Gaming
Topic: Minecraft Pi Edition not working
Replies: 32
Views: 12649

Re: Minecraft Pi Edition not working

Guys, when I run Mincraft on my Pi/Pi+ on my 42" screen in full screen mode (1080P) I find that I am was only able to select just over half the choices from the inventory (option "E"), top half only. Otherwise I've not had other issues, just got to be careful not to get dizzy. To access the bottom h...
by RaspISteve
Sat Aug 29, 2015 1:17 am
Forum: Troubleshooting
Topic: USB Micro not working on raspberry pi 2
Replies: 5
Views: 3003

Re: USB Micro not working on raspberry pi 2

Guys, If it helps... I've just bought the StarTech USB sound 'card' and found this thread among others to get it going. I struggled at first, followed the info on Adafruits pages, used "alsamixer" to select my USB audio dongle, wind all the agains up and tried various arecord/aplay attempts stabbing...
by RaspISteve
Wed Mar 11, 2015 10:46 pm
Forum: Beginners
Topic: High Amp Motors with the Pi
Replies: 18
Views: 10050

Re: High Amp Motors with the Pi

Bwag, not sure you're in the right place here. Those motors represent some serious power and together with the currents involved your system represents a major risk to health if things get out of control. If you skimp on any aspect of the control system a failure could present a huge risk of injury....
by RaspISteve
Sat Jan 31, 2015 5:09 pm
Forum: Automation, sensing and robotics
Topic: Capacitors
Replies: 6
Views: 1729

Re: Capacitors

Perhaps worth adding is that although electrolytic capacitors are good at steadying a power rail they tend to be a little inductive meaning they aren't good for absorbing fast spikes. Quite often you will see an electrolytic in parallel with a disc ceramic begging the question: "what's the point of ...
by RaspISteve
Tue Jan 27, 2015 11:32 pm
Forum: Advanced users
Topic: Measure delay in transmitting bytes via uart
Replies: 2
Views: 638

Re: Measure delay in transmitting bytes via uart

sochinho, are you being asked to determine the latency between and new character arriving/leaving the UART and the point at which the Pi is actively dealing with it or between characters arriving/leaving the UART. If it's just leaving/arriving in the UART the internal buffering will hid all of it. R...
by RaspISteve
Mon Jan 26, 2015 12:23 am
Forum: Automation, sensing and robotics
Topic: NiCD State of Charge
Replies: 2
Views: 616

Re: NiCD State of Charge

Richard, I've seen smart NiCd charging circuits use a system of charge then test cycles to charge the things. The test relies on a power transistor switching a load across the battery while the terminal voltage is measured. The actual loading occurs in a very short time else the battery never gets c...
by RaspISteve
Sun Jan 25, 2015 11:58 pm
Forum: Automation, sensing and robotics
Topic: Powering a 12v motor
Replies: 4
Views: 1209

Re: Powering a 12v motor

Rock, all you need is a power transistor capable of handling the voltage and current that the fan/motor needs and driving it via one of the pulse width generator outputs. If you drive a 50% duty cycle into the motor driver circuit then the 'average' voltage will be half the supply. Vary the duty cyc...
by RaspISteve
Mon Jan 05, 2015 9:05 pm
Forum: Media centres
Topic: raspbmc setup
Replies: 8
Views: 1728

Re: raspbmc setup

Guys, I had a bit of new-year Pi enthusiasm and revisited my various SD images. When I tried the once "WiFi dongle working" raspBMC I found the wireless network wouldn't connect and the scan mode failed to see anything. Changed to wired and completed a full update but still no joy with the WiFi dong...
by RaspISteve
Thu Dec 25, 2014 9:48 pm
Forum: Automation, sensing and robotics
Topic: sensor for opening door
Replies: 2
Views: 636

Re: sensor for opening door

Yag, Have a look at reed switches. The reed switch is a little set of contacts usually set in a small glass vile that get triggered by a magnet. Basically the contacts open/close (don't recall which) when adjacent to a magnet. These things are usually quite cheap and the contacts are usually impervi...
by RaspISteve
Sun Nov 02, 2014 6:19 pm
Forum: Automation, sensing and robotics
Topic: 230v current sensor
Replies: 2
Views: 1532

Re: 230v current sensor

dsgashi, Your thread title is for a 'current sensor' which I assume you're wanting to confirm current flow in the target application and feed this information back into the Raspberry. A 230vac relay across the switched supply will only confirm that it should be working. If this is good enough but yo...
by RaspISteve
Fri Aug 29, 2014 9:03 pm
Forum: Automation, sensing and robotics
Topic: Switch Circuit
Replies: 8
Views: 1569

Re: Switch Circuit

What you won't be able to do easily is join it up to real time inputs and outputs and other than pure simulation adding a real battery will be out of the question. Thank you! I think that will definitely help! I will look into the posts from this forum. But what exactly do you mean by "pure simulat...
by RaspISteve
Thu Aug 28, 2014 10:10 pm
Forum: Automation, sensing and robotics
Topic: Switch Circuit
Replies: 8
Views: 1569

Re: Switch Circuit

At last! Sounds like you want to investigate circuit simulation which usually involves some form of schematic entry system to define your circuit design followed by the host emulating the equivalent of what you've entered. Whether the necessary software exists the way you want it for the Pi is anoth...
by RaspISteve
Tue Aug 26, 2014 9:28 pm
Forum: Automation, sensing and robotics
Topic: Switch Circuit
Replies: 8
Views: 1569

Re: Switch Circuit

rkear89, I would suggest you go and start reading the Magpi emag from issue 1 to date to get the necessary background and work through it to see what folk are doing with their Pi and maybe pillage from there. Maybe invest in one of the increasing number of add-on boards to avoid having to deal with ...
by RaspISteve
Thu Aug 21, 2014 11:45 am
Forum: Beginners
Topic: Brushless Motor run via Rpi
Replies: 8
Views: 2207

Re: Brushless Motor run via Rpi

S, <snip>. As I recall the pulse stream needed has a rate around 50Hz and a pulse of 1.5mSec as neutral with +/- 0.5mSec to go forward/reverse. At this duty cycle you are unlikely to see a LED blinking because of our eye's response time and it'll be very dim given the 1/20th duty cycle. You might g...
by RaspISteve
Wed Aug 20, 2014 9:17 pm
Forum: Beginners
Topic: Brushless Motor run via Rpi
Replies: 8
Views: 2207

Re: Brushless Motor run via Rpi

S, Just a thought but you say when you connect a LED it blinks. If you are using one of the many brushless controllers aimed at the model car/boat/plane world it'll be expecting a very particular signal. As I recall the pulse stream needed has a rate around 50Hz and a pulse of 1.5mSec as neutral wit...
by RaspISteve
Mon Aug 11, 2014 8:53 pm
Forum: Advanced users
Topic: write in C to uart only outputs 16 bytes? [solved]
Replies: 14
Views: 2172

Re: write in C to uart only outputs 16 bytes ?

Guys, I remember years ago there was a UART which came with a 16 byte FIFO buffer. Very useful if you couldn't always get to it on time as you could whack a load of characters at it then go off and do something else. If you didn't check the right flags and waited for characters to flush out correctl...
by RaspISteve
Tue Jul 22, 2014 9:51 pm
Forum: Advanced users
Topic: High Power Stepper Motor
Replies: 15
Views: 4958

Re: High Power Stepper Motor

Guys, there's been a couple of folk here playing with step motors on various applications and going DIY on the driver which is OK for the little noddy applications. However, this topic is for a "High Power Stepper Motor". It can save a lot of headaches by using a commercial module to do all the hard...
by RaspISteve
Tue Jul 22, 2014 2:04 pm
Forum: Advanced users
Topic: High Power Stepper Motor
Replies: 15
Views: 4958

Re: High Power Stepper Motor

Guys, If you're needing to drive a 'High Power Stepper Motor' and do it reliablely you need a proper driver and power supply able to keep it all going. In essence steppers and motors in general run on current going through the coils. The more current then the more power. The problem is to get the ne...
by RaspISteve
Sat Jul 19, 2014 2:53 pm
Forum: Advanced users
Topic: 4 Phase Stepper Motor and CNC Application
Replies: 13
Views: 4279

Re: 4 Phase Stepper Motor and CNC Application

Tommy, Did you really look at the stuff I pointed you at in http://www.raspberrypi.org/forums/viewtopic.php?f=29&t=80766 ? Heard nothing so I assumed you'd cracked it. I see now you still have some way to go. Those modules (and a big power supply) will solve most of the problems. You will maybe need...
by RaspISteve
Sat Jul 05, 2014 10:45 pm
Forum: Advanced users
Topic: Raspberry Pi CNC
Replies: 2
Views: 1840

Re: Raspberry Pi CNC

Tom, I sounds like you need to fill the gap between your Pi and the stepper motors. You might want to start here: http://homepage.cs.uiowa.edu/~jones/step/ for background info (there are other (and better) sources). You've already got a bunch of H-driver devices and you'll need a big power supply pl...
by RaspISteve
Sat Jun 21, 2014 6:40 am
Forum: Troubleshooting
Topic: Help increasing rpm of stepper motor
Replies: 26
Views: 7675

Re: Help increasing rpm of stepper motor

Landerson, you could use a simple electric motor as rotating actuator. Essentially a rotating solenoid. You could bias the armature with a small spring and limit the rotation (or kick) using two end stops maybe with sensors or switches. When you want to 'kick' just switch some (or a lot of) current ...

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