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by hippy
Tue Jul 17, 2018 7:07 pm
Forum: General discussion
Topic: "Low depth" power supply
Replies: 6
Views: 168

Re: "Low depth" power supply

eludlow wrote:
Tue Jul 17, 2018 4:18 pm
Does anyone know if a "slim" power supply supply is available?
I created one by cutting a mains PSU apart, extracting the PCB, soldering mains lead to come out one end, with 5V out the other. That was then secured in a slim plastic case.
by hippy
Tue Jul 17, 2018 5:48 pm
Forum: General programming discussion
Topic: What Does Hiding the Details of I/O in Library Calls Teach?
Replies: 19
Views: 339

Re: What Does Hiding the Details of I/O in Library Calls Teach?

Yes, no problem with libraries etc etc, but at some point (not too late on) expose them to actually controlling a GPIO pin raw so they know what's in a library call. Why though? I see the important thing being to provide people with the means of achieving what they want to achieve and if they want ...
by hippy
Mon Jul 16, 2018 6:38 pm
Forum: Automation, sensing and robotics
Topic: Detect where Pi is physically docked
Replies: 9
Views: 198

Re: Detect where Pi is physically docked

laagland wrote:
Mon Jul 16, 2018 6:17 pm
This will work perfectly, thanks! :)
Any chance of saying which "this" it is which you have chosen ?
by hippy
Mon Jul 16, 2018 4:30 pm
Forum: Automation, sensing and robotics
Topic: Detect where Pi is physically docked
Replies: 9
Views: 198

Re: Detect where Pi is physically docked

Also, more than 2 docks should be possible. If you need to identify one of a number of docks you can extend the third pin open / short to 0V solution to each dock having a different resistor in each. You can measure the resistance, using a voltage divider and ADC or the time taken to discharge a ca...
by hippy
Mon Jul 16, 2018 4:15 pm
Forum: Automation, sensing and robotics
Topic: Detect where Pi is physically docked
Replies: 9
Views: 198

Re: Detect where Pi is physically docked

You could create special power cables at each location which can identify themselves. This is interesting, how would that work? One solution would be to provide power to your Pi via a 3 or more pin connector, XLR, DIN or anything similar. One pin 0V, one pin 5V, another pin left open circuit for on...
by hippy
Mon Jul 16, 2018 4:06 pm
Forum: Other projects
Topic: "Airbag" Case
Replies: 3
Views: 107

Re: "Airbag" Case

You can run rubber tubing or foam pipe lagging around the edge of a Pi PCB or even mount it inside a rubberised phone case. Simplest solution is probably to sandwich it between two lumps of polystyrene with elastic bands. I am not sure of the need to protect a Pi board. If it had an LCD fitted it wo...
by hippy
Mon Jul 16, 2018 3:49 pm
Forum: Python
Topic: Tkinter + socket programming
Replies: 10
Views: 372

Re: Tkinter + socket programming

You don't need to launch the Tkinter root.mainloop() as a separate thread, can just invoke it as you did originally.
by hippy
Mon Jul 16, 2018 3:20 pm
Forum: Beginners
Topic: Can I using wi-fi connect two pi's together without a hotspot?
Replies: 13
Views: 248

Re: Can I using wi-fi connect two pi's together without a hotspot?

lets forget that we are using the Wi-Fi "layer" and think of only using TCP/IP by itself. I am sure that using the basic TCP/IP routines one can communicate between Is without a router. Correct. For a wired network; just connect one device's RJ45 to the other device's RJ45. They can both communicat...
by hippy
Mon Jul 16, 2018 3:07 pm
Forum: Automation, sensing and robotics
Topic: Detect where Pi is physically docked
Replies: 9
Views: 198

Re: Detect where Pi is physically docked

If connected to something that could be used to reveal what it is connected to as suggested. A trace route might help if there's an internet connection. You could just add a switch. Though, for an automatic determination, perhaps a compass chip or something could be used if it is reliably oriented d...
by hippy
Mon Jul 16, 2018 1:05 pm
Forum: Add-ons
Topic: Hardware Specification of the RPi's
Replies: 22
Views: 475

Re: Hardware Specification of the RPi's

bonzadog wrote:
Mon Jul 16, 2018 9:47 am
Well, the question has been answered: No Spec from RPi but some by other people.
I don't believe that is the case at all. Perhaps you could detail a necessary specification which has not been officially provided ?
by hippy
Mon Jul 16, 2018 12:55 pm
Forum: Beginners
Topic: Can I using wi-fi connect two pi's together without a hotspot?
Replies: 13
Views: 248

Re: Can I using wi-fi connect two pi's together without a hotspot?

Thanks for the unfortunate info but as an old retired engineer, I want to know why UI need an access point. Setting up the communication medium and what that handles are two separate things. WiFi requires one thing to be a master and the rest to be slaves. That master will normally be a router or a...
by hippy
Mon Jul 16, 2018 11:42 am
Forum: Beginners
Topic: How to restore rewritten version of CSV file?
Replies: 11
Views: 248

Re: How to restore rewritten version of CSV file?

Embarrassingly overwriting old data with new and losing the previous data is something everyone will probably do at some point. Two techniques to avoid that are - Create every file with a unique file name, often using a time stamp, adjusted or with some extra sequencing number to ensure there are no...
by hippy
Sun Jul 15, 2018 5:17 pm
Forum: Other projects
Topic: Question about safe shutdown
Replies: 2
Views: 70

Re: Question about safe shutdown

Added: Sorry; misread that as "without breadboard".

Solder your wires direct to the switch and other components ?

Some additional context to your question may help provide more appropriate responses.[/i]
by hippy
Sun Jul 15, 2018 5:13 pm
Forum: Troubleshooting
Topic: File attachments
Replies: 6
Views: 105

Re: File attachments

I just tried to attach a .txt. file to a reply and it was rejected. What is the best way to include text file data in a reply?.....RDK If it's not too large you could include it in-line wrapped in [ code ] ... [ /code ] tags which will preserve its spacing. If it is too large it might be worth aski...
by hippy
Sun Jul 15, 2018 2:07 pm
Forum: Troubleshooting
Topic: Pi 3B+ / Shorting 3.3V to GND
Replies: 14
Views: 292

Re: Pi 3B+ / Shorting 3.3V to GND

There is a chip (U8, a XR77004) on the 3B+ which contains most of the circuitry for some DC-DC converters. I was about to say the same. I would have expected that to include short-circuit, over-current and thermal shutdown protections which would contain the failure and avoid the polyfuse 'blowing'...
by hippy
Sat Jul 14, 2018 12:37 pm
Forum: Add-ons
Topic: Hardware Specification of the RPi's
Replies: 22
Views: 475

Re: Hardware Specification of the RPi's

I have some technical literature about the RPi's but nothing that is of real meaning. Jamesh is currently creating / compiling / collating a single Technical FAQ but I believe nearly all the technical information you are seeking is already documented and publicly available, albeit spread around a l...
by hippy
Fri Jul 13, 2018 1:20 pm
Forum: Off topic discussion
Topic: Connecting leads to a button/coin battery
Replies: 5
Views: 227

Re: Connecting leads to a button/coin battery

Clothes peg? Wrap a wire around each of the two ends. Clamp the cell between them. You can add drawing pins pushed into both sides of the jaws to get a good contact. Just file away any lacquer on them if there is any. Solder the wire to the drawing pin spike. Another alternative is to put the butto...
by hippy
Fri Jul 13, 2018 1:16 pm
Forum: Python
Topic: Tkinter + socket programming
Replies: 10
Views: 372

Re: Tkinter + socket programming

maybe it's because socket.recv will be blocking by default so your loop will spend most of it's time there waiting for bytes to arrive and you will only be able to stop it while you are receiving data. I had a Tkinter program which had to update a 'progress bar' as data was sent and received and th...
by hippy
Fri Jul 13, 2018 12:56 pm
Forum: Beginners
Topic: Serial connection troubleshooting
Replies: 10
Views: 255

Re: Serial connection troubleshooting

The manual states that the device sends information every 2 seconds with this message format: <ISOTOPE>: <VALUE><UNIT>. For instance "I-131: 185 MBq" If that is literally the case then ser.readline() may not what you want to use as there won't be any end of line received to terminate what has been ...
by hippy
Thu Jul 12, 2018 8:55 pm
Forum: Add-ons
Topic: Can I switch one Pi off/on with another?
Replies: 11
Views: 257

Re: Can I switch one Pi off/on with another?

Just pulling the RUN pin low will reset / reboot a Pi which can easily be done from another Pi using just a wire from one of its GPIO pins. It's not recommended but likely no worse than pulling the power if that's the alternative and it avoids having to actually disconnect the power, saves on mechan...
by hippy
Thu Jul 12, 2018 11:14 am
Forum: General discussion
Topic: Thinking of writing a technical FAQ
Replies: 53
Views: 1209

Re: Thinking of writing a technical FAQ

How it works: All edits are done to the github repo as markdown. Every hour or so this is automatically translated to HTML pages and published under www.raspberrypi.org/documentation/. I have no problem with that, it is how most content management systems handle things; raw content in a simple to e...
by hippy
Thu Jul 12, 2018 12:24 am
Forum: Python
Topic: Distribute python gui app
Replies: 1
Views: 117

Re: Distribute python gui app

Just send them your Python source code and instructions for installing the version of Python it uses plus TKInter. For Windows you might want to create a .pyw wrapper which launches your application. You will also have to ensure you have made your app cross-platform compatible. Other than that, if i...
by hippy
Thu Jul 12, 2018 12:19 am
Forum: General discussion
Topic: Thinking of writing a technical FAQ
Replies: 53
Views: 1209

Re: Thinking of writing a technical FAQ

Another -

Can I combine two Pi to make a better / faster Pi ?
by hippy
Wed Jul 11, 2018 7:52 pm
Forum: Beginners
Topic: Only 0.01V on the 3.3V pin and fails to boot
Replies: 6
Views: 223

Re: Only 0.01V on the 3.3V pin and fails to boot

The 3V3 on a Pi 3B+ is generated by the PMIC chip, as are 1V8 and some other voltages. It might be worth checking those as well. My guess is they are all down; either a PMIC issue or something causing it to not enable power output. Contacting the supplier for return, testing, repair or replacement, ...
by hippy
Wed Jul 11, 2018 7:45 pm
Forum: General discussion
Topic: Thinking of writing a technical FAQ
Replies: 53
Views: 1209

Re: Thinking of writing a technical FAQ

Another one for the FAQ -

How many USB devices / hubs can I attach and use with a Pi ?

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