Go to advanced search

by PiGraham
Thu Oct 25, 2018 3:14 pm
Forum: Graphics, sound and multimedia
Topic: Raspberry Pi (any model) as a midi encoder and interface
Replies: 6
Views: 506

Re: Raspberry Pi (any model) as a midi encoder and interface

There are some Python MIDI libraries that you could use to issue MIDI commands or play notes when keys are pressed.
Here's one. https://pypi.org/project/pymidi/

Something here may be relevant
http://andrewdotni.ch/blog/2015/02/28/m ... spberry-p/
by PiGraham
Thu Oct 25, 2018 10:00 am
Forum: Graphics, sound and multimedia
Topic: Raspberry Pi (any model) as a midi encoder and interface
Replies: 6
Views: 506

Re: Raspberry Pi (any model) as a midi encoder and interface

A PC keyboard has over 100 keys so there might be an option to hack a standard keyboard controller. To do your own matrix scan of 49 keys that's 7 x 7 or 14 gpio lines which should be straight forward. You can use some Arduino models as matrix scanning devices over a serial or USB interface if you h...
by PiGraham
Wed Oct 24, 2018 10:55 am
Forum: General discussion
Topic: DIY POE?
Replies: 32
Views: 1413

Re: DIY POE?

I realise it doesn't meet the zero cost requirement but if wanting to poe multiple devices then simple poe hubs can be a good solution. For example https://www.ebay.co.uk/itm/5-Ports-4-PoE-Injector-Power-Over-Ethernet-Switch-without-Power-Adapter/222561142253?hash=item33d1ad85ed:g:8P0AAOSwnK9ZUlPY ...
by PiGraham
Wed Oct 17, 2018 11:58 am
Forum: General discussion
Topic: 8 channel CCTV with Pi 3 B
Replies: 8
Views: 241

Re: 8 channel CCTV with Pi 3 B

A kit of 8ch analogue DVR and 4 cameras is probably your cheapest and easiest option. Have you looked on eBay? Aliexpress, banggood etc should also have lots of cheap options. Here's one that includes four cameras to add to the four you already have. Excludes disk drive, so if you have one spare you...
by PiGraham
Fri Oct 12, 2018 10:47 am
Forum: Automation, sensing and robotics
Topic: Object detection robot using raspberry pi
Replies: 3
Views: 297

Re: Object detection robot using raspberry pi

It will be a simpler task if you only have to detect which of a few simple shapes is in view. You can tell the difference between triangle, square and circle (for example) just by measuring the ratio of perimeter to surface area. You can get those values from "blob labelling". See OpenCV FindContour...
by PiGraham
Fri Oct 05, 2018 9:26 am
Forum: Other projects
Topic: Passcode activated start for car
Replies: 7
Views: 345

Re: Passcode activated start for car

Given the potential costs even if you are only stranded at the side of the road and need a recovery truck, it makes sense to pay for a device professionally designed for this purpose. You may even find it reduces your insurance costs rather than invalidating you cover.
by PiGraham
Thu Oct 04, 2018 1:15 pm
Forum: Other projects
Topic: Passcode activated start for car
Replies: 7
Views: 345

Re: Passcode activated start for car

If you have worked out all the caveats mentioned and want to go ahead the start-up time might be tackled : By using an Arduino which starts in a couple of seconds at most when using the bootloader or instantly if you burn you code as the boot code. Using Pi you could take a look at Ultibo which I be...
by PiGraham
Mon Oct 01, 2018 2:53 pm
Forum: Automation, sensing and robotics
Topic: Angle robot to certain angle
Replies: 5
Views: 255

Re: Angle robot to certain angle

Basically trying to replicate below robot https://www.youtube.com/watch?v=TmicYvL9QII /Chetan S. It looks like that uses the line sensor to detect when the robot has turned far enough. The sensor they use is four points, two that fall on the black line and two that fall outside the black line. Roug...
by PiGraham
Mon Oct 01, 2018 7:55 am
Forum: Automation, sensing and robotics
Topic: Angle robot to certain angle
Replies: 5
Views: 255

Re: Angle robot to certain angle

Are there lines to follow at those angles? If so you can rotate until you detect the exit line at 90, 180 or 270 then start following that. In general you can turn by an angle by driving forward on one side and back on the other for a particular time / speed (dc motor) or number of steps (stepper mo...
by PiGraham
Tue Sep 25, 2018 9:30 am
Forum: Advanced users
Topic: Netflix no longer runs on Pi
Replies: 15
Views: 1907

Re: Netflix no longer runs on Pi

gkreidl wrote:
Mon Sep 24, 2018 2:56 pm

Why not try a working solution instead of complaining that it doesn't work any more in Chromium? And it will definitely work better in kodi than inside any browser on the RPi.
Than you for your helpful solution.
by PiGraham
Mon Sep 24, 2018 9:49 am
Forum: Beginners
Topic: GPIO Pin Audio Speaker, how?
Replies: 13
Views: 1058

Re: GPIO Pin Audio Speaker, how?

Nonsense. The Pi B models use gpio to generate the audio coming out of the TRRS jack. A 4R speaker resistance is too low to be driven directly from a GPIO pin. Agreed, although that is mostly an issue in dc conditions if the gpio is held on, or off. Also, loudspeakers are inductive loads that will ...
by PiGraham
Mon Sep 24, 2018 7:48 am
Forum: Assistive technology and accessibility
Topic: Sight for the Blind for <100$
Replies: 712
Views: 122933

Re: Sight for the Blind for <100$

The camera module for the pi is OK, but it has a narrow field of view. something like 65-80 degrees whereas a wide angle lens will get 120+ degrees. You can buy wide angle lenses for the raspberry pi module, or you could use another webcam that has a wide angle lens built in. That is what we did fo...
by PiGraham
Mon Sep 24, 2018 7:41 am
Forum: Assistive technology and accessibility
Topic: Sight for the Blind for <100$
Replies: 712
Views: 122933

Re: Sight for the Blind for <100$

Hello, Folks... Pimoroni have come up with a Pi Zero with official Pi camera connector.. at a very low price. This unit is now shaved down as thin as possible.. with a single core processor. So maybe a lightweight head mounted basic vOICe without extras could be realised? john Can you provide a lin...
by PiGraham
Fri Sep 21, 2018 8:59 am
Forum: Beginners
Topic: LED project help, please?
Replies: 7
Views: 283

Re: LED project help, please?

An Aduino based on ATTiny chip that has battery connection built in is a giood choice for compact battery powered devices. Adafruit Trinket is one example. I like the Digispark / Digidtump boards that are super cheapon eBay, Banggood etc. Consider also ESP 8266 or ESP 32 boards You can of course use...
by PiGraham
Fri Sep 21, 2018 7:16 am
Forum: Other projects
Topic: Dot matrix paper feeder ideas
Replies: 11
Views: 509

Re: Dot matrix paper feeder ideas

To answer the first, each sheet layer is attached to the first by a perforated strip, this ensures that it doesn't get separated like you mentioned. Sample sheet.jpeg This is a rough procedure of what i was looking to implement. The pi would help control the mechanics and time the driving in accord...
by PiGraham
Thu Sep 20, 2018 7:42 am
Forum: General discussion
Topic: Pixy Camera
Replies: 11
Views: 5635

Re: Pixy Camera

I hope by now the community has gained a better understanding of the incredible utility of the Pixy Camera. This thing will allow a Raspberry Pi based robot to detect and recognize objects via "vision". Well, Pi based robots are using vision already, and some vision on Pi is much more sophisticated...
by PiGraham
Wed Sep 19, 2018 5:59 pm
Forum: Networking and servers
Topic: Extending Wifi Signal
Replies: 9
Views: 1790

Re: Extending Wifi Signal

Try it and see. It might work. Your best chance is to get the antennas high up (>2m, but roof level if you can). Avoid any vegetation in between. If you have a directional antenna to link to the cottage you may need an omnidirectional antenna to provide all round coverage at the remote end, although...
by PiGraham
Tue Sep 18, 2018 8:23 am
Forum: Other projects
Topic: Dot matrix paper feeder ideas
Replies: 11
Views: 509

Re: Dot matrix paper feeder ideas

I think there are indeed solutions to this probem available from the printer manufacturers. Loading Special Paper You can use carbonless multipart forms of up to six parts (five copies on top of the original). Make sure you set the paper-thickness lever to the proper position based on the number of ...
by PiGraham
Tue Sep 18, 2018 8:19 am
Forum: Other projects
Topic: Dot matrix paper feeder ideas
Replies: 11
Views: 509

Re: Dot matrix paper feeder ideas

mahir wrote:
Tue Sep 18, 2018 8:05 am
So here's a gif of the process:
Image

I hope it clears things up.
Now try hand-feeding one sheet from the bottom of a pile of 20+ of those forms. How easy Is that?
by PiGraham
Tue Sep 18, 2018 8:16 am
Forum: Other projects
Topic: Dot matrix paper feeder ideas
Replies: 11
Views: 509

Re: Dot matrix paper feeder ideas

I think this is a much harder problem than you imagine. Even modern printers get paper jams, and these are mechanisms that have been honed over decades by lots of the best mechanical designers. Paper is tricky to push. A stack of 20 mutli-sheet forms seems like a difficult thing to auto-feed. How do...
by PiGraham
Mon Sep 17, 2018 4:25 pm
Forum: Graphics, sound and multimedia
Topic: Circular Display
Replies: 3
Views: 400

Re: Circular Display

We need a batch of 50 pcs for a project. Most of the circular display on AE are based on MIPI interface which is not available directly from RPI Pi has mipi DSI port for display. The official TFT uses a MIPI port. kernel drivers are available and this thread suggests that people who know what they ...
by PiGraham
Mon Sep 17, 2018 12:26 pm
Forum: General discussion
Topic: DIY POE?
Replies: 32
Views: 1413

Re: DIY POE?

Sadly, as far as we know, the LAN7800 chip doesn't support a fallback mode to 100Mbit/s should the extra pairs not be available. There is still an open enquiry with Microchip over this. If you are missing the pairs then the link will simply not come up. "[email protected]" is a Boradcom term. Pres...
by PiGraham
Mon Sep 17, 2018 10:29 am
Forum: Beginners
Topic: Illuminated push button
Replies: 41
Views: 1251

Re: Illuminated push button

You are probably right on that. Back to my LED question I was intending to use it as a status lamp, ie LED on when Pi is active and LED off to tell me that Pi has gone to bed and I can pull the supply if I want to. Two potential issues have come up - 1. over-current and the possible need for a resi...
by PiGraham
Mon Sep 17, 2018 10:00 am
Forum: General discussion
Topic: Raspberry Pi is a waste of time (and money).
Replies: 115
Views: 5171

Re: Raspberry Pi is a waste of time (and money).

I'd argue if a responder doesn't "have the time, energy or inclination to compose and expansive solution or explanation" then maybe it's better to not reply I completely disagree with you there. It is ridiculous to expect contributors to "compose expansive solutions". Who has time to do that on dem...
by PiGraham
Mon Sep 17, 2018 8:11 am
Forum: General discussion
Topic: DIY POE?
Replies: 32
Views: 1413

Re: DIY POE?

POE equipment compatible with the 802.3af/t standards doesn't just put voltage on the wire. It negotiates what voltage to provide (up to 57 volts and power up to 30W). A DIY system would have to do that if the supply device is 802.3af/t compliant. Info about that is in the wiki https://en.wikipedia....

Go to advanced search