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by drgeoff
Sat May 26, 2018 12:47 pm
Forum: General discussion
Topic: Will my setup explode or something?
Replies: 1
Views: 28

Re: Will my setup explode or something?

Do you really expect anyone to give you a reliable answer to a question with so many unknowns?

I don't think it will explode. I don't think the plastic will melt. I don't think you need a fan. But no guarantee that any of those will prove to be correct.
by drgeoff
Fri May 25, 2018 5:32 pm
Forum: General discussion
Topic: DIY UPS controlled by raspberry pi3
Replies: 1
Views: 74

Re: DIY UPS controlled by raspberry pi3

My crystal ball isn't showing me whether this is to be a UPS for the RPi itself or a UPS for other mains powered equipment.
by drgeoff
Fri May 25, 2018 10:43 am
Forum: Beginners
Topic: Raspberry pi 3 b+ with powerbank
Replies: 16
Views: 245

Re: Raspberry pi 3 b+ with powerbank

It is almost always the case that the specs of powerbanks give the claimed ampere-hour capacity of the internal cell. The average voltage of the cell is only about 3.7 volts. So even if the capacity figure is accurate and the conversion efficiency were 100%, the run time would only be about 74% of t...
by drgeoff
Fri May 25, 2018 12:14 am
Forum: Networking and servers
Topic: Call forward via SIM card
Replies: 2
Views: 129

Re: Call forward via SIM card

Doing this using a RPi is is non-trivial for several reasons including : RPis have no analogue inputs. In many countries it is illegal to connect uncertified equipment to PSTN lines. That effectively rules out a homebrew interface. One approach that will work but does not use a RPi is: 1. Get an Obi...
by drgeoff
Thu May 24, 2018 8:01 pm
Forum: Troubleshooting
Topic: stuck with green and red light
Replies: 9
Views: 281

Re: stuck with green and red light

okey far as i understood from answers cpu is dead so if i can find a screen dead old phone or device that constains Broadcom BCM2835 cpu i can replace that dead cpu and i can fix my raspberry pi, uhmm lets say in the theory :lol: In theory maybe. In practice your chances of success are close to zero.
by drgeoff
Thu May 24, 2018 7:54 pm
Forum: Beginners
Topic: Parallel or multi-tasking functionality
Replies: 4
Views: 118

Re: Parallel or multi-tasking functionality

A digital phone calls needs about 100 kbit/s in each direction. You are going to need a lot of simultaneous calls in progress before they become an issue in the network bandwidth arena. However, "CPU bandwidth" is a different matter as conversational audio does not like latency. So think about a ded...
by drgeoff
Thu May 24, 2018 12:12 pm
Forum: General discussion
Topic: Noobie, be gentle - signal conversion question
Replies: 7
Views: 272

Re: Noobie, be gentle - signal conversion question

I have purchased said converter but it doesn't work for my application. They are powered through handshake lines which are unused in this application and merely flip the bits and correct the voltage. I need to seperate the positive and negative voltages on the A and B lines in the ttl end to get an...
by drgeoff
Wed May 23, 2018 10:47 pm
Forum: Advanced users
Topic: MP2636 not enough
Replies: 4
Views: 155

Re: MP2636 not enough

The datasheet clearly says that the charging current is determined by RS1 and Riset. The datasheet also tells you what pins of the IC those are connected to. Given that, you have no excuse for expecting me to go searching for how the module you have is physically laid out.
by drgeoff
Wed May 23, 2018 10:34 pm
Forum: Beginners
Topic: how to run and install TeamVewer on old Pi Zero ?
Replies: 6
Views: 168

Re: how to run and install TeamVewer on old Pi Zero ?

Hi all Can old pi zero rune TeamVewer ? And If any know how to install it plz let me know. https://community.teamviewer.com/t5/Knowledge-Base/How-to-install-TeamViewer-for-Linux/ta-p/6318 ARMv7 Architecture supported, the Zero is ARMv6.. so no the zero cant run temvewer ? From the already linked pa...
by drgeoff
Wed May 23, 2018 4:59 pm
Forum: Beginners
Topic: Use an npn transistor to connect a fan?
Replies: 9
Views: 205

Re: Use an npn transistor to connect a fan?

There is no such thing as a "3.3v npn transistor".

Depends on the fan but almost any 5 inch or smaller 5 volt fan can be handled by almost any NPN small signal transistor. 2N3904, 2N2222, BC107 etc. You also need a base resistor, say 330 ohms.

But why do you think your RPi needs a fan?
by drgeoff
Wed May 23, 2018 3:30 pm
Forum: Advanced users
Topic: MP2636 not enough
Replies: 4
Views: 155

Re: MP2636 not enough

Imperf3kt wrote:
Wed May 23, 2018 9:16 am
I assume this is because charging the battery is taking most of the current? The datasheet says it charges at up to 2.5A.
You can verify this by (temporarily?) setting the charge current to a low value. See page 31, "Charge Current Setting".
by drgeoff
Wed May 23, 2018 3:09 pm
Forum: Beginners
Topic: Arduino Uno + Raspberry Pi3
Replies: 2
Views: 70

Re: Arduino Uno + Raspberry Pi3

RPis have no analogue inputs. Whether it is better to add an ADC to the RPi or use the ADC capability of an Arduino depends on many factors, none of which you have mentioned.
by drgeoff
Wed May 23, 2018 1:40 pm
Forum: Troubleshooting
Topic: RPi LED driving problems
Replies: 5
Views: 138

Re: RPi LED driving problems

you mentioned you connected "LED w/ a 50ohm resistor", most likely this is a 51ohm green-brown-black resistor. If this is the case then the current flowing to the circuit for a red/yellow LED would be around 63mA or 0.063A which is more than 3 times the typical value of an LED. For a green/blue it ...
by drgeoff
Tue May 22, 2018 2:26 pm
Forum: General discussion
Topic: Raspberry Power Charger
Replies: 3
Views: 113

Re: Raspberry Power Charger

Raspberryapplepi wrote:
Mon May 21, 2018 5:28 pm
Hi I want to create a small Raspberry computer and I want to be able to charge it through the wall socket
No model of RPi to date requires charging. (They do need to be powered, which is not the same thing.)
by drgeoff
Tue May 22, 2018 1:38 pm
Forum: Off topic discussion
Topic: I would like to create a Call Alerter based off of Caller ID
Replies: 4
Views: 286

Re: I would like to create a Call Alerter based off of Caller ID

If you add up the price of a RPi, PSU, SD card, POTS/PSTN modem, screen, and perhaps a keyboard* and protective case it will exceed that of a ready-to-use call-blocker.

(* keyboard needed if you want the device to be standalone and capable of easy editing of number database.)
by drgeoff
Tue May 22, 2018 1:30 pm
Forum: General discussion
Topic: Thermal power dissipated by a processor OF raspberry
Replies: 1
Views: 93

Re: Thermal power dissipated by a processor OF raspberry

Your request is insufficiently precise. You need to be aware of the following.

1. The Broadcom SoCs incorporate more than ARM CPU(s)

2. The SoC in some RPis has a single CPU. Others have 4 CPUs.

3. The power dissipated in the SoC is dependent to some degree on what the CPU(s) is/are doing
by drgeoff
Tue May 22, 2018 1:25 pm
Forum: General discussion
Topic: STICKY: PMs being turned off from June 13
Replies: 21
Views: 770

Re: STICKY: PMs being turned off from June 13

Those of you who have used the private messaging system on this forum over the last year will have received an email from us explaining that we're reluctantly going to have to turn the function off, "Used" appears to mean sending only, ie does not include receiving. I have received 4 PMs within the...
by drgeoff
Mon May 21, 2018 8:31 pm
Forum: Mathematica
Topic: [Question] Perimeter
Replies: 12
Views: 280

Re: [Question] Perimeter

B.Goode wrote:
Mon May 21, 2018 6:25 pm
Go to the Mathematics Department of your University and ask them to teach you some (Cartesian) coordinate geometry.
Surely anyone in a University faculty doing this project would have already been taught coordinate geometry at school.
by drgeoff
Mon May 21, 2018 8:27 pm
Forum: Beginners
Topic: how to run and install TeamVewer on old Pi Zero ?
Replies: 6
Views: 168

Re: how to run and install TeamVewer on old Pi Zero ?

Yes, but to connect a network interface (ethernet or Wi-Fi), a keyboard and possibly a mouse you will need a USB hub. From there on it isn't really any different from installing and using TeamViewer on any variety of B model RPi.
by drgeoff
Mon May 21, 2018 7:10 pm
Forum: Beginners
Topic: Using a shared resistor on different LEDS?
Replies: 4
Views: 125

Re: Using a shared resistor on different LEDS?

Hi, im fairly new to GPIO and I've hooked up one resistor to Ground and split the cable up to 12 GPIO inputs. Can that work? if yes, how? Which resistor to use? Thanks, Sese_the_Coder 1. You don't connect LEDs to GPIO inputs . :) 2. You can use one resistor for multiple LEDs, especially if you only...
by drgeoff
Mon May 21, 2018 4:53 pm
Forum: Beginners
Topic: Building a Wheatstone bridge
Replies: 7
Views: 239

Re: Building a Wheatstone bridge

Why don't you ask whoever told you that a RPi or Arduino would be useful?

What usefulness are you desirous to have?

A Wheatstone bridge is analogue. RPis have no analogue inputs.
by drgeoff
Mon May 21, 2018 3:16 pm
Forum: Beginners
Topic: Raspbian is a challenge
Replies: 7
Views: 236

Re: Raspbian is a challenge

stressed wrote:
Mon May 21, 2018 2:53 pm
And a wifi keyboard is a Rii K12+ 2.4 wireless keyboard. Referred to by the manufacturer as a wifi keyboard.
http://www.riitek.com/product/k12.html has no mention of Wi-Fi.
by drgeoff
Mon May 21, 2018 3:09 pm
Forum: Troubleshooting
Topic: Is it possible to repair a RPi B3 HDMI port?
Replies: 5
Views: 132

Re: Is it possible to repair a RPi B3 HDMI port?

jamesh wrote:
Mon May 21, 2018 2:24 pm
If that's not the issues, I suspect the Pi HDMI is dead, not sure there is anything you can do to fix it.
i'm sure. :(
by drgeoff
Mon May 21, 2018 3:07 pm
Forum: Troubleshooting
Topic: I cannot get my Pi to connect to the internet
Replies: 9
Views: 237

Re: I cannot get my Pi to connect to the internet

Okay, I've changed the power supply and the PI's red light now stays solid. I have downloaded advanced IP scanner as suggested, but still the PI cannot be found. The green light still only flickers for about 5 seconds, I'm not sure if that is ordinary or not ? Any other suggestions before I just bu...
by drgeoff
Mon May 21, 2018 2:57 pm
Forum: General discussion
Topic: Battery power / power display in termial
Replies: 3
Views: 106

Re: Battery power / power display in termial

The 'Lite' is irrelevant. Without extra hardware there is no way that any model of RPi with any OS and any software can monitor the state of the battery, never mind display it to you.

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