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by PiGraham
Tue Feb 06, 2018 1:57 pm
Forum: Automation, sensing and robotics
Topic: Bar billiard project.
Replies: 10
Views: 559

Re: Bar billiard project.

I should have added that the scripts for the MCP3008 and the Matrix display are in concurrent threads, so maybe I have a threading issue. I think you will have problems if you try to use one SPI resource from two separate threads without synchronisation. GPIOZero with pigpio has something called Pi...
by PiGraham
Tue Feb 06, 2018 1:44 pm
Forum: General discussion
Topic: Pin set as pull-up has delay on reading pin low value
Replies: 5
Views: 204

Re: Pin set as pull-up has delay on reading pin low value

We are confident that it is not our software the reason of delayed read. Same source code is used for reading high/low status of another sensor type which sends digital output 0/1 with a max response time 1ms. We set pin status to down for that sensor type and expect a pin high instead of pin low. ...
by PiGraham
Tue Feb 06, 2018 1:26 pm
Forum: Automation, sensing and robotics
Topic: What's the lightest, reliable external pull-up I can use?
Replies: 14
Views: 691

Re: What's the lightest, reliable external pull-up I can use?

I'm guessing the 1M pull-up is built-in to the device, and is that high to keep currents small. Why not use the Pi's internal 50k pull-up to 3v3 as well? Hopefully JRA will clarify, but I read it as concern that the FET will not be able to pull the input low if the pull-up is less than 1M because t...
by PiGraham
Tue Feb 06, 2018 11:29 am
Forum: Other projects
Topic: Retrofitting an old projector
Replies: 4
Views: 285

Re: Retrofitting an old projector

I have an old slide projector, I'm wondering if there is a cheap way to output the equivalent of a slide from a Pi? Same form-factor as a 35mm slide frame would be perfect, but hacking the slide holder is a possibility. Changing/adding optical lenses is less desirable I guess (fitting, cost, dust.....
by PiGraham
Tue Feb 06, 2018 11:09 am
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 1350

Re: Powered by XLR cable "Phantom Power" (+48V 14mA)?

As I suggested earlier, T off the audio signal into your device and nick some phantom power. Do not convert to digital and back again to forward on to the desk. You'll save a bunch of power and remove all latency concerns. The function of measuring tuning accuracy can then be a much simpler job (an...
by PiGraham
Tue Feb 06, 2018 10:41 am
Forum: Automation, sensing and robotics
Topic: Bar billiard project.
Replies: 10
Views: 559

Re: Bar billiard project.

If the slots are dark enough, just shining a certain colour light on the ball and using the LDR should be enough. A red or white ball illuminated with red light will both show as red. A red ball illuminated with blue or green light will show as black, but the white ball will show as blue or green. ...
by PiGraham
Tue Feb 06, 2018 9:44 am
Forum: Camera board
Topic: Sensor Cable Extension?
Replies: 12
Views: 535

Re: Sensor Cable Extension?

RaTTuS wrote:
Tue Feb 06, 2018 9:29 am
https://shop.pimoroni.com/products/rasp ... era-module for the Zero
That's the one!
by PiGraham
Tue Feb 06, 2018 9:36 am
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 1350

Re: Powered by XLR cable "Phantom Power" (+48V 14mA)?

fohman, Ah, I see, so you want us to advise on your scheme to make money. For free? I'm inclined to tune out at this point but... ..this is aimed for on-the-go musicians who want to do a bit of pitch practicing before they record their tracks or perform live. So basically the idea is like those gui...
by PiGraham
Tue Feb 06, 2018 9:31 am
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 1350

Re: Powered by XLR cable "Phantom Power" (+48V 14mA)?

What I feel that I really need is a way to find people who might want to help me complete this project for some negotiated amount of pay based on a finished product. How do I find such people? Sites like Upwork and Toptal are problematic because you have to pay up front for the time spent explainin...
by PiGraham
Tue Feb 06, 2018 9:25 am
Forum: Camera board
Topic: Sensor Cable Extension?
Replies: 12
Views: 535

Re: Sensor Cable Extension?

I saw this camera and it would be perfect except for two problems: 1) it uses the older CMOS sensor with slightly worse resolution (not the end of the world but certainly not ideal), and 2) I think it contains an IR filter (this is not an option). If it doesn't contain an IR filter then it would pr...
by PiGraham
Tue Feb 06, 2018 9:14 am
Forum: Automation, sensing and robotics
Topic: What's the lightest, reliable external pull-up I can use?
Replies: 14
Views: 691

Re: What's the lightest, reliable external pull-up I can use?

The open-drain N-FET has a typical sink spec of 10uA but could be as low as 7uA. Thus the 1Mohm pull-up as part of the 5.2V to 3.3V level shifting resistor divider. The standard internal pull-up value would be to strong for the N-FET. You have a FET that can only sink 10uA? That seems improbable. D...
by PiGraham
Mon Feb 05, 2018 5:04 pm
Forum: Python
Topic: How to make an input trigger the output once no matter how long input is high
Replies: 5
Views: 263

Re: How to make an input trigger the output once no matter how long input is high

This might help with the button: https://www.raspberrypi.org/forums/viewtopic.php?t=33020 Try working through the tutorial here: https://projects.raspberrypi.org/en/projects/physical-computing Just skip bits if you don't have the acessories like LEDs and breadboards, although getting the parts and d...
by PiGraham
Mon Feb 05, 2018 2:46 pm
Forum: Camera board
Topic: Sensor Cable Extension?
Replies: 12
Views: 535

Re: Sensor Cable Extension?

Would something like this help?
Image
by PiGraham
Mon Feb 05, 2018 11:40 am
Forum: Beginners
Topic: Drag Race Light Tree - Pinewood Derby
Replies: 6
Views: 237

Re: Drag Race Light Tree - Pinewood Derby

rpiMike wrote:
Mon Feb 05, 2018 10:56 am
Or the Speaker pHat: https://shop.pimoroni.com/products/speaker-phat
Possibly although I suspect a (much) louder speaker is required. Does the PHAT have a line out? I don't see it.
by PiGraham
Mon Feb 05, 2018 10:51 am
Forum: Beginners
Topic: Drag Race Light Tree - Pinewood Derby
Replies: 6
Views: 237

Re: Drag Race Light Tree - Pinewood Derby

Since the arduino does not have native sound output, i assume a pi (i would like to use a zero for this) is my best bet. Sorry to be the bearer of bad news, but the Pi Zero only outputs digital audio through its HDMI port. It does not have an analog audio port like the other models. You can add an ...
by PiGraham
Mon Feb 05, 2018 10:21 am
Forum: Off topic discussion
Topic: Why does the 'Pi' exist?
Replies: 64
Views: 2803

Re: Why does the 'Pi' exist?

This is such a stupid thread. Everyone jumps like trained seals to insult OP and his motives. People should have just left it alone. When I first saw this thread, I kept saying to myself "Will people have the sense to just leave this alone or will they jump in and try to "help" the OP - as if he we...
by PiGraham
Mon Feb 05, 2018 10:14 am
Forum: Python
Topic: How to make an input trigger the output once no matter how long input is high
Replies: 5
Views: 263

Re: How to make an input trigger the output once no matter how long input is high

I have a python code that plays a sound when I push a button, but if I hold the button, it keeps playing the sound, which I dont want So basically I have a circuit and I flip the switch and I need the led to blink one and stay off even if the switch is still on, so what line would I add to my pytho...
by PiGraham
Mon Feb 05, 2018 10:01 am
Forum: Troubleshooting
Topic: How do I know the DISPLAY variable for a headless setup of Raspberry Pi 3?
Replies: 2
Views: 124

Re: How do I know the DISPLAY variable for a headless setup of Raspberry Pi 3?

Hello, I have my Raspberry Pi 3 model B setup as a headless system. I am able to do the following: - connect via ssh - connect HDMI cable to my projector - display videos on the projector. Do you mean you doot headless (no display / projector connected then hotplug HDMI to the projector and try to ...
by PiGraham
Mon Feb 05, 2018 9:32 am
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 1350

Re: Powered by XLR cable "Phantom Power" (+48V 14mA)?

fohman, I want to run a Raspberry Pi using the "phantom power" from an audio mixer to process a microphone signal in a certain way I think we are missing something important here. As is often the case. What is it you actually want to do? In what "certain way" do you want to process a microphone sig...
by PiGraham
Mon Feb 05, 2018 9:24 am
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 1350

Re: Powered by XLR cable "Phantom Power" (+48V 14mA)?

What hardware would you suggest? I don't know. It's a big topic You haven't defined the requirements that well. Can't existing equipment do everything you want to do (EQ etc)? If someone buys a 32 channel RIO why wouldn't they get one EQ etc in the rack? This is not the place to discuss such open q...
by PiGraham
Mon Feb 05, 2018 8:44 am
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 1350

Re: Powered by XLR cable "Phantom Power" (+48V 14mA)?

It won't work. You would need a device that can supply >1000 mW (200mA @5V) The equipment you want to use only provides 672mW (14mA @ 48V) Use equipment that supports digital phantom power designed to power electronics or forget it. You almost certainly don't need or want Linux and you definitely ne...
by PiGraham
Mon Feb 05, 2018 8:16 am
Forum: General discussion
Topic: Touch screen 15ft away from Pi.. can it be done?
Replies: 21
Views: 946

Re: Touch screen 15ft away from Pi.. can it be done?

Copyright wrote:
Sun Feb 04, 2018 9:50 pm
Just a heads up.. the extension I got from amazon WORKS! I was able to use the touch screen through an HDMI cable for extending the ribbon cable. Touch works as well.
Good news. Thanks for letting us know.
by PiGraham
Mon Feb 05, 2018 8:14 am
Forum: General discussion
Topic: Powered by XLR cable "Phantom Power" (+48V 14mA)?
Replies: 35
Views: 1350

Re: Powered by XLR cable "Phantom Power" (+48V 14mA)?

It seems to depend on aht phsntom poawer system you use. Digital microphones complying with the AES 42 standard may be provided with phantom power at 10 volts, impressed on both audio leads and ground. This supply can furnish up to 250 mA to digital microphones. A keyed variation of the usual XLR co...
by PiGraham
Fri Feb 02, 2018 7:39 pm
Forum: Camera board
Topic: USB webcam and software that supports zoom
Replies: 5
Views: 261

Re: USB webcam and software that supports zoom

Do you want a zoom - an adjustable lens that can range from wide angle to telephoto, or do you just need a long telephoto lens for looking at objects at a distance? The adjustability of a zoom lens makes it more complex. If you can just fit a telephoto lens and lave it in place that's much simpler. ...
by PiGraham
Fri Feb 02, 2018 3:00 pm
Forum: Camera board
Topic: USB webcam and software that supports zoom
Replies: 5
Views: 261

Re: USB webcam and software that supports zoom

English is my language and I would prefer using a USB webcam, not the RPi camera. I've used it before and its resolution is not good enough for this task, that's why I'm looking for camera/software combination that would give me good resolution and adjustable zoom. Thanks for the reply. You have a ...

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