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by PiGraham
Fri Jan 19, 2018 4:50 pm
Forum: General discussion
Topic: Best Small Cheap Way To Power A Pi
Replies: 11
Views: 293

Re: Best Small Cheap Way To Power A Pi

Thanks for the replies. The 18650 batteries look like good value and capacity. Also, the lipo batteries are good value and capacity as well. However, I heard connecting lipo batteries in parallel is dangerous. I will probably opt for the 18650 batteries as they can easily be bought and need less pr...
by PiGraham
Fri Jan 19, 2018 10:18 am
Forum: General discussion
Topic: Cheapest power solution
Replies: 19
Views: 1281

Re: Cheapest power solution

Imperf3kt wrote:
Thu Jan 18, 2018 11:16 pm

I based it on personal experience with roughly a dozen different devices I ripped apart myself.

In other words, speculation based on personal experience.
I apologize if I misled anyone.
It was a genuine question and if it's based on your direct experience that's as valid as anyone else's
by PiGraham
Fri Jan 19, 2018 9:44 am
Forum: Beginners
Topic: I need someone make my code
Replies: 18
Views: 580

Re: I need someone make my code

:roll: Hi dudes :roll: I’m making a project and I need a software for my raspberry. These are the specifications for the code. I’ll use a ultrasound sensor. I need that when the sensor detects something in one meter, a buzzer starts making noise. When it is to 75cm to make the noise faster, in 50cm...
by PiGraham
Fri Jan 19, 2018 9:26 am
Forum: General discussion
Topic: Best Small Cheap Way To Power A Pi
Replies: 11
Views: 293

Re: Best Cheap Lipo Batteries For Pi

Sorry Graham. I am looking for a battery around 120mm x 100mm. I am looking for 3000 mah+ battery life. 2AH and smaller: Read the safety info! https://shop.pimoroni.com/products/lipo-battery-pack You should look at the WH capcity of a battery rather than mAH. A mAH number will typically be at the s...
by PiGraham
Thu Jan 18, 2018 6:34 pm
Forum: General discussion
Topic: Best Small Cheap Way To Power A Pi
Replies: 11
Views: 293

Re: Best Cheap Lipo Batteries For Pi

Power banks are definitely good value for money and a good way to power a Pi but are either too thick or too big for the project I have in mind. I was trying to answer the question you asked. You haven't told us anything about size or shape requirements or what you are trying to do. Something else ...
by PiGraham
Thu Jan 18, 2018 5:49 pm
Forum: General discussion
Topic: Best Small Cheap Way To Power A Pi
Replies: 11
Views: 293

Re: Best Cheap Lipo Batteries For Pi

Don't use bare LiPos. Always use protection circuit and proper charger. USB power packs can be good value. I bought one of these as a gift for some one. Seemed well made and I haven't heard any complaints but I can't tell you much about it. https://www.amazon.co.uk/TeckNet-Portable-PowerCrest-10000m...
by PiGraham
Thu Jan 18, 2018 1:02 pm
Forum: General discussion
Topic: HELP!Can I use Raspberry Pi's HDMI port to transfer data?
Replies: 12
Views: 272

Re: HELP!Can I use Raspberry Pi's HDMI port to transfer data?

it can be done, HDMI ports have an I2C line. Someone has done it on the Pi too: https://www.raspberrypi.org/forums/viewtopic.php?t=44445&p=452512 Can I use this method to transmit the data collected by the camera? Thank you ! emily.holder You really need to say what you want to achieve to get usefu...
by PiGraham
Thu Jan 18, 2018 11:01 am
Forum: General discussion
Topic: HELP!Can I use Raspberry Pi's HDMI port to transfer data?
Replies: 12
Views: 272

Re: HELP!Can I use Raspberry Pi's HDMI port to transfer data?

What data do you want to transfer? Why do you want to use HDMI to send it? Simple control messages an be sent via CEC, usually selecting channels, adjusting volume and so on. I think HDMI 1.4 includes an Ethernet channel but according to this topic Raspberry Pi doesn't support it. It might work for ...
by PiGraham
Thu Jan 18, 2018 9:04 am
Forum: General discussion
Topic: Cheapest power solution
Replies: 19
Views: 1281

Re: Cheapest power solution

So I bought these four products from the dollar tree. I want to know legitimate answers on how they would work with a Raspberry Pi, WITHOUT looking at the price of these: https://imgur.com/a/hjbGS Those (and pretty much every other "lighter socket USB adaptor") are just a 12 supply (car Lead Acid b...
by PiGraham
Wed Dec 06, 2017 1:35 pm
Forum: Beginners
Topic: Continuous rotation servo control.
Replies: 6
Views: 287

Re: Continuous rotation servo control.

pcmanbob wrote:
Wed Dec 06, 2017 12:52 pm
So the reason your servo does not stop is because you have not told it to.
Agreed.

It may be the case that no PWM signal will stop the servo.
If not it may be necessary to maintain the mid-position signal and not quit with GPIO.Cleanup().
by PiGraham
Wed Dec 06, 2017 8:41 am
Forum: Media centres
Topic: Skype + Raspberry pi
Replies: 9
Views: 3285

Re: Skype + Raspberry pi

No recommendations, I only know what I read in these pages,, but this looks interesting as a Skype alternative:

http://www.instructables.com/id/Video-C ... erry-Pi-3/

https://www.linux-projects.org/uv4l/tut ... itsi-meet/

It seems not to need binaries and is open source.
by PiGraham
Wed Nov 29, 2017 10:56 am
Forum: General discussion
Topic: Scanning serial UART ports
Replies: 3
Views: 160

Re: Scanning serial UART ports

You can read the Rx pin as a general input. If it's state when driven by the device's Tx output is different to the state when open circuit you should be able to detect that the device is plugged in. You can probably just read it like any gpio. You can't tell what is connected unless the something t...
by PiGraham
Sat Nov 11, 2017 9:33 am
Forum: Beginners
Topic: Detect hot shoe trigger from analogue camera
Replies: 10
Views: 506

Re: Detect hot shoe trigger from analogue camera

just a thought about another way to tackle this. You could use a car GPS GSM tracker. these can send an SMS of position, date, time when a button is pressed. You could wire the flash sync to the button contacts. It could also be used to locate the camera if you lose it. Battery and gps stuff already...
by PiGraham
Thu Nov 09, 2017 3:15 pm
Forum: Beginners
Topic: Detect hot shoe trigger from analogue camera
Replies: 10
Views: 506

Re: Detect hot shoe trigger from analogue camera

You can get hotshow adaptors designed to connect off-cara flash units. They generally take a hotshoe flash in top as well to you can tap off the flash contact to the Pi and still have a way to use a flash is desired. Be careful though, some flash guns can have high voltages on the shoe contacts. Us ...
by PiGraham
Tue Nov 07, 2017 2:36 pm
Forum: General discussion
Topic: Extending Wireless Range
Replies: 55
Views: 2573

Re: Extending Wireless Range

You all worry too much. The point is not to do whatever illegal acts you can get away with. These laws exist for good purposes and it makes sense to comply with them to avoid interfering with other peoples' Wi-Fi and other equipment. Everyone benefits if we are not blasted with signals from every W...
by PiGraham
Tue Nov 07, 2017 11:22 am
Forum: Gaming
Topic: ZXBaremulator v2.0
Replies: 3
Views: 460

Re: ZXBaremulator v2.0

by PiGraham
Tue Nov 07, 2017 8:18 am
Forum: General discussion
Topic: Extending Wireless Range
Replies: 55
Views: 2573

Re: Extending Wireless Range

]Once again, the authorities are not going to come after you if you are using the Hats or Breadboards to hack something together to make a better mousetrap. That is why I and thousands of others who grew up during the Home Brew Computer days, are not running around with tinfoil on our heads. At thi...
by PiGraham
Tue Nov 07, 2017 6:44 am
Forum: Beginners
Topic: Which hardware to buy: Simple sign project, Stranger Things
Replies: 5
Views: 306

Re: Which hardware to buy: Simple sign project, Stranger Things

I agree "neopixels" are the obvious choice. Something like this https://i.ebayimg.com/images/g/XMQAAOSwMORW7SXw/s-l500.jpg https://www.ebay.co.uk/itm/DC-5V-50PCS-WS2811-RGB-Full-Color-12mm-Pixels-digital-Addressable-LED-String-CC/162705886727?_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D...
by PiGraham
Mon Nov 06, 2017 7:09 am
Forum: Automation, sensing and robotics
Topic: L293D troubleshooting for IR camera cut control
Replies: 28
Views: 6426

Re: L293D troubleshooting for IR camera cut control

Hi, Great information. Cheers :) One question, where would be the best place put a LDR sensor in your circuit? Thanks. Diogo Why do you need an LDR when you have an image sensor? Take a picture and measure brightness from that. If the average is below some threshold then it's too dark and you shoul...
by PiGraham
Mon Oct 30, 2017 11:52 am
Forum: Advanced users
Topic: How to transmit binary values with serial port
Replies: 23
Views: 2949

Re: How to transmit binary values with serial port

I am new to serial port communication and facing similar problem of receiving junk values while using putty.. Hi, mrmuffins hope you have resolved the issues ,if yes request you to guide me . I am trying to send some string data from raspberry pi3 but getting similar display while using putty as yo...
by PiGraham
Sun Oct 29, 2017 7:02 pm
Forum: Automation, sensing and robotics
Topic: Proximity or Line Crossing Sensor System
Replies: 3
Views: 240

Re: Proximity or Line Crossing Sensor System

Maybe you could use RFID tags and readers. Are the horses already tagged? Sure Flap cat doors have an RFID detector coil around the outer aperture that reads the implanted tag on in the neck when the cat puts its head up to the flap. Perhaps a much larger coil could be places around each of several ...
by PiGraham
Fri Oct 27, 2017 1:07 pm
Forum: Networking and servers
Topic: How to get a Raspberry Pi to communicate over 10km (6 miles)
Replies: 13
Views: 1161

Re: How to get a Raspberry Pi to communicate over 10km (6 miles)

This video hows 10km range with ESP32 and high gain antenna. A Pi could possibly do something similar. IIRC the Pi3 has pads on board that can be used for external antenna connection. https://hackaday.io/project/10091-raspberry-pi-3-external-antenna You could also look at LoRa. https://www.youtube.c...
by PiGraham
Fri Oct 27, 2017 9:42 am
Forum: Beginners
Topic: Controlling Solenoid Valve
Replies: 7
Views: 550

Re: Controlling Solenoid Valve

If you are prepared to motorise a manual valve there are a few options. Mixer valves are designed to mix flows. Cheap thermostatic radiator valves operate by pressing on a valve with an expanding wax-filled cylinder in the control knob. If you remove the knob the actuating button of the valve is exp...
by PiGraham
Mon Oct 23, 2017 8:55 am
Forum: Beginners
Topic: Controlling Solenoid Valve
Replies: 7
Views: 550

Re: Controlling Solenoid Valve

Do solenoid Valves only have two settings i.e Full Open or Full Closed...there is no way to get them to only open 30% (this is only an example) ? If this is the case that they can only open and close, what would you recommend I use to open a valve certain increments? Typically yes, solenoid valves ...
by PiGraham
Tue Oct 17, 2017 6:31 am
Forum: General discussion
Topic: Remote email printing
Replies: 5
Views: 364

Re: Remote email printing

They have a POS system, touch screen front counter, touch screen in prep area for call in with POS receipt printer in prep area (doesn't have a problem with flour). I think you're thinking another touch display over the prep area. Would require me to start an entirely new business. The current POS ...

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