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by PiGraham
Wed Apr 25, 2018 4:29 pm
Forum: Beginners
Topic: Ipad to TV through RPi (Ipad-wifi-Rpi-HDMI-TV)
Replies: 9
Views: 126

Re: Ipad to TV through RPi (Ipad-wifi-Rpi-HDMI-TV)

I think you can do that with Kodi.

Here's a guide:
https://www.youtube.com/watch?v=Q0WUHG3RSII


You can install Kodi in Raspbian

Code: Select all

sudo apt-get install kodi
Or you can run a media centre distribution like openELEC or RaspBMC
by PiGraham
Wed Apr 25, 2018 1:00 pm
Forum: General programming discussion
Topic: Making robot follow gps
Replies: 6
Views: 146

Re: Making robot follow gps

You might get aswers to specific issues for underwater ROVs at https://www.openrov.com/
by PiGraham
Wed Apr 25, 2018 7:29 am
Forum: Advanced users
Topic: Mean of 60 temperature sensors
Replies: 6
Views: 137

Re: Mean of 60 temperature sensors

Hi All, I want to maintain the temperature of three levels of my building (company), and they are quite large in area. I have planned to mount temperature sensors with some distance at different spots on my ceilings, making a total of around 50-60 sensors on each level. I plan to gather the tempera...
by PiGraham
Wed Apr 25, 2018 7:23 am
Forum: General discussion
Topic: Controlling three solenoid valves with 12 mA limit
Replies: 18
Views: 458

Re: Controlling three solenoid valves with 12 mA limit

A voltage drop of 2.5V is specified that implies that the output voltage is within 2.5V of the supply rails. SO if you power the sensor with 12V the output would go to between (12-2.5) and 12V I'd use an opto-isolator with LED and series resistor as the load driven by the sensor and the phototransis...
by PiGraham
Tue Apr 24, 2018 8:55 am
Forum: General discussion
Topic: Controlling three solenoid valves with 12 mA limit
Replies: 18
Views: 458

Re: Controlling three solenoid valves with 12 mA limit

The question about the proximity sensor...they say the output is PNP but they don't say which of the transistor terminals (Collector or Emitter) is brought out so you don't know if it wants to go to ground through a resistor or to V+ through a resistor. At least I can't see which...maybe I am missi...
by PiGraham
Tue Apr 24, 2018 7:18 am
Forum: Camera board
Topic: Why does the IR flood light cover make the image less blurry?
Replies: 2
Views: 95

Re: Why does the IR flood light cover make the image less blurry?

I can't think of a reason why removing a cover round a light should affect focus of a fixed-focus lens camera. OTOH light from the LEDs that hits the lens could reduce contrast which might be interpreted as 'blurry' or 'foggy'. You could try making a little lens hood from tinfoil to keep any stray l...
by PiGraham
Mon Apr 23, 2018 3:48 pm
Forum: Gaming
Topic: Running Half-Life on Raspberry Pi?
Replies: 5
Views: 237

Re: Running Half-Life on Raspberry Pi?

rpiMike wrote:
Mon Apr 23, 2018 3:20 pm
Looks like it is possible with Exagear:

https://www.youtube.com/watch?v=A2_ZEo9N_fM
That would not be an enjoyable gaming experience.
by PiGraham
Mon Apr 23, 2018 2:47 pm
Forum: Troubleshooting
Topic: PiCamera preview in high resolution
Replies: 5
Views: 158

Re: PiCamera preview in high resolution

AH, I may have missed the key info there. You can run full HD OK in all configurations except when raspi2raspi is running? If raspi2raspi is using GPU to scale the image, as seems likely, then there is a heavy load on the GPU to support full display and camera and mirror to 7". Maybe you are running...
by PiGraham
Mon Apr 23, 2018 12:44 pm
Forum: Graphics, sound and multimedia
Topic: A "simple" instrument
Replies: 12
Views: 192

Re: A "simple" instrument

There seems to be a bit of conflict between "simple" and the level of control you want. How about http://zynthian.org/ with Dexed FM synth plugin? It looks like you can add as much complexity and control as you like. Well, I thought it was simple. I basically only want to be able to play a sine wav...
by PiGraham
Mon Apr 23, 2018 12:26 pm
Forum: Troubleshooting
Topic: PiCamera preview in high resolution
Replies: 5
Views: 158

Re: PiCamera preview in high resolution

I use raspi2raspi from Andrew to mirror the screen from the 7" primary screen to the HDMI. It works well. Shouldn't you be mirroring the HDMI to the TFT? Then the HD preview will naturally be HD and the small display will get a scaled-down copy. Going the other way surely scales-up a low res image ...
by PiGraham
Mon Apr 23, 2018 8:34 am
Forum: Graphics, sound and multimedia
Topic: A "simple" instrument
Replies: 12
Views: 192

Re: A "simple" instrument

kirre wrote:
Sun Apr 22, 2018 9:36 pm
Next thing is, i want to have five knobs on the box that I'll build that control Attack, Release, Time and Feedback (on the delay), and a volume knob.

Is that a reverb? You want to control it per note?
by PiGraham
Mon Apr 23, 2018 8:30 am
Forum: Graphics, sound and multimedia
Topic: A "simple" instrument
Replies: 12
Views: 192

Re: A "simple" instrument

There seems to be a bit of conflict between "simple" and the level of control you want.
How about

http://zynthian.org/ with Dexed FM synth plugin?

It looks like you can add as much complexity and control as you like.
by PiGraham
Fri Apr 20, 2018 9:16 pm
Forum: General discussion
Topic: IoT based Attendance Recording System
Replies: 22
Views: 456

Re: IoT based Attendance Recording System

Has anyone got experience of a system that worked well? I would say most systems work well but it depends on what one is intending to achieve, how one defines 'well', and how much abuse will be tolerated. Good point. I guess the objective is to improve on the fingerprint system and minimise error a...
by PiGraham
Fri Apr 20, 2018 4:28 pm
Forum: General discussion
Topic: IoT based Attendance Recording System
Replies: 22
Views: 456

Re: IoT based Attendance Recording System

It has to be iris scanners as shown in Minority Report.

Well, that or the spiders!
by PiGraham
Fri Apr 20, 2018 3:56 pm
Forum: General discussion
Topic: IoT based Attendance Recording System
Replies: 22
Views: 456

Re: IoT based Attendance Recording System

What I never really get is why we need an in and an out RFID sensor (or in your case or in/out for finger prints). If you swipe and the time has been long enough, you are then not what you where before ? Otherwise why swipe. Thing is students could turn up at the door twice a day just to swipe the ...
by PiGraham
Fri Apr 20, 2018 3:52 pm
Forum: General discussion
Topic: IoT based Attendance Recording System
Replies: 22
Views: 456

Re: IoT based Attendance Recording System

Has anyone got experience of a system that worked well?
by PiGraham
Fri Apr 20, 2018 11:25 am
Forum: Automation, sensing and robotics
Topic: Automated mower for a large yard
Replies: 10
Views: 5189

Re: Automated mower for a large yard

Petrol or electric? For a DIY effort I would assume electric motor and battery power for ease of control. That also allows autonomous refueling which I think is far too dangrous to do with petrol.
by PiGraham
Fri Apr 20, 2018 9:11 am
Forum: Automation, sensing and robotics
Topic: Automated mower for a large yard
Replies: 10
Views: 5189

Re: Automated mower for a large yard

Why not start with an actual lawn mower and robotize it?
That gives you a sturdy structure with safety cowl, cut height adjustment and grass collection. Replace wheels / roller with steering / powered wheels. Add sensors and control system
by PiGraham
Fri Apr 20, 2018 9:05 am
Forum: General discussion
Topic: IoT based Attendance Recording System
Replies: 22
Views: 456

Re: IoT based Attendance Recording System

I assume that almost all students carry a Wi-Fi or Bluetooth enabled device around campus. If those radios are on they can be tracked. https://www.crc.id.au/tracking-people-via-wifi-even-when-not-connected/ Of course there are various ways in which that can be defeated, from turning the radios off t...
by PiGraham
Fri Apr 20, 2018 8:37 am
Forum: General discussion
Topic: IoT based Attendance Recording System
Replies: 22
Views: 456

Re: IoT based Attendance Recording System

What is the purpose of the system, to count who turns up at the gate? To check that students are on campus during the day? To know how many people are on site? Is it supposed to relate in some way to attendance in classes? It might be in students' interests to defeat such a system by logging high nu...
by PiGraham
Fri Apr 20, 2018 7:37 am
Forum: General discussion
Topic: IoT based Attendance Recording System
Replies: 22
Views: 456

Re: IoT based Attendance Recording System

Heater wrote:
Fri Apr 20, 2018 6:46 am
I'm curious. Why is there a need to know if students are coming in or going out? Or that they are there at all?

During all my years in Technical College, then University, nobody was continuously, intrusively, monitoring our attendance.
Good point
by PiGraham
Thu Apr 19, 2018 7:46 pm
Forum: Other languages
Topic: How do I compile a Visual Basic program for the Pi?
Replies: 7
Views: 221

Re: How do I compile a Visual Basic program for the Pi?

I'm not sure of the details but Mono on Linux allows you to run dotnet CLR programs but visual basic support may be lacking on Raspbian

http://www.mono-project.com/docs/about- ... sualbasic/

https://stackoverflow.com/questions/477 ... spberry-pi
by PiGraham
Thu Apr 19, 2018 6:20 pm
Forum: Python
Topic: Pushbutton controlling multiple LED's
Replies: 3
Views: 87

Re: Pushbutton controlling multiple LED's

Note that gpiozero has when_held events for buttons in addition to WhenPressed so you could do both functions with one button if you like. The WhenPressed function increments the count to light LEDs and a long hold on the button does the reset. You could consider using a strip of "neopixels" (WS2812...

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