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by RattusRattus
Wed Sep 09, 2020 8:55 am
Forum: Beginners
Topic: Interface problem between Arduino and RPI, through pin 7 arduino. and pin 7 RPI
Replies: 10
Views: 339

Re: Interface problem between Arduino and RPI, through pin 7 arduino. and pin 7 RPI

You initially said that when you read the input from you Arduino it was all over the place. Connecting an LED will not tell you if it is a steady state or oscillating if the line is switching often enough. Please consider the initial steps I suggested and perhaps share a drawing of what is connected...
by RattusRattus
Mon Sep 07, 2020 4:05 pm
Forum: Beginners
Topic: Interface problem between Arduino and RPI, through pin 7 arduino. and pin 7 RPI
Replies: 10
Views: 339

Re: Interface problem between Arduino and RPI, through pin 7 arduino. and pin 7 RPI

Hi there First lets find out if your problem is on the Arduino or RPi... i.e. is the problem writing data out or reading it in? Instead of connecting your Arduino to pin 7 of your Pi attach Pin 7 of your Pi to 0V. (1) When you try and read the pin does it always show 0? (2) now connect pin 7 of your...
by RattusRattus
Mon Sep 07, 2020 3:48 pm
Forum: Beginners
Topic: How to add and control Fan in RPi4 without other power source
Replies: 11
Views: 525

Re: How to add and control Fan in RPi4 without other power source

Take a look at the fan shim

even if you don't use the shim hardware there is plenty of cribs available in the supporting code...

https://learn.pimoroni.com/tutorial/san ... h-fan-shim
https://github.com/pimoroni/fanshim-python

/Andy
by RattusRattus
Mon Sep 07, 2020 1:48 pm
Forum: Troubleshooting
Topic: issues with GPIO/button push
Replies: 1
Views: 73

Re: issues with GPIO/button push

hi there Switches are just bits of metal that you join together or pull apart when you close or open them. During the transition from open to closed the switch contacts will often bounce a few times before coming to rest in their new closed state. This may take a few microseconds (millionths of a se...
by RattusRattus
Tue Sep 01, 2020 3:26 pm
Forum: General discussion
Topic: Reading LM75X, i.e. LM75A product id?
Replies: 1
Views: 161

Re: Reading LM75X, i.e. LM75A product id?

just to be clear
#1 can you read any other registers correctly?
#1.1 perhaps only the reading of temperature register works? in which case you are probably not selecting the register mapping correctly (temperature is the default register map)


/Andy
by RattusRattus
Tue Sep 01, 2020 3:13 pm
Forum: HATs and other add-ons
Topic: Need some help with getting better temp readings with my Sense Hat ...
Replies: 8
Views: 414

Re: Need some help with getting better temp readings with my Sense Hat ...

try "dupont cable female-female" in your search - found loads on ebay, 200mm is a common length but 100 and 150mm is available
by RattusRattus
Fri Aug 28, 2020 3:28 pm
Forum: Compute Module
Topic: EMC Certificate for DSI1 on CM3+
Replies: 4
Views: 456

Re: EMC Certificate for DSI1 on CM3+

But - as you recommended - we want to try out filters on the lines. Regarding to that have some questions to you: [1] Do you also use LRC networks for differential lanes like HDMI? [2] Do you have any recommendation for multiple LRC-networks in a single IC package or do you usually build it up with...
by RattusRattus
Fri Aug 21, 2020 7:39 pm
Forum: Beginners
Topic: Raspberry Pi GPIO Timed Circuit
Replies: 4
Views: 196

Re: Raspberry Pi GPIO Timed Circuit

Hi Sudopigeek and welcome to the Pi forums You say that for your "certain board" you need to connect two pins together for ~1s in order to power it. Without further information on the "certain board" then the only sure way to operate the device is to join those two lines together...
by RattusRattus
Fri Aug 21, 2020 6:57 pm
Forum: Compute Module
Topic: EMC Certificate for DSI1 on CM3+
Replies: 4
Views: 456

Re: EMC Certificate for DSI1 on CM3+

Displays are notoriously bad when it comes to EMC. I found that the most important issues tend to be a simple low pass filter and PCB layout. A simple LRC low pass filter set to Fclk x 1.5 on ALL lines to the display at the domain boundary is essential, much, much better than ferrite beads. Paying c...
by RattusRattus
Fri Aug 21, 2020 3:21 pm
Forum: Automation, sensing and robotics
Topic: Integerating MPU 9250 sensor data with GPS
Replies: 3
Views: 281

Re: Integerating MPU 9250 sensor data with GPS

Inertial navigation involves starting at a known position at time T0 and then calculating your position at Time T1 based on the rate of acceleration and directional vector that you have received from your accelerometer. Assuming that you start with a good GNSS fix you know where you are. (T0) Given ...
by RattusRattus
Thu Jan 09, 2020 11:43 pm
Forum: Beginners
Topic: 1pps generation from raspberry Pi
Replies: 2
Views: 535

Re: 1pps generation from raspberry Pi

Short answer: No. There will always be jitter caused by the OS performing context switches for other tasks (and the operation of the OS itself) Now that jitter may be small enough that you don't notice it but your gpio edges will not not be always exactly 1 second apart long answer: Before Python 3....
by RattusRattus
Thu Jan 09, 2020 11:14 pm
Forum: Beginners
Topic: Question about sources.list
Replies: 4
Views: 310

Re: Question about sources.list

deb URL buster main contrib non-free rpi The components main contrib and non-free contain packages that are found in the debian distribution: o main consists of DFSG-compliant packages, which do not rely on software outside this area to operate. These are the only packages considered part of the Deb...
by RattusRattus
Thu Jan 09, 2020 10:47 pm
Forum: Beginners
Topic: tee command to listen in on the serial port
Replies: 2
Views: 254

Re: tee command to listen in on the serial port

The tee command will only allow you to log what is sent to stdout (i..e what you see on your screen) unless you are see the sort of information you are wanting to capture going by onscreen then tee isn't the command you are looking for - sorry
by RattusRattus
Fri Sep 27, 2019 2:40 pm
Forum: General discussion
Topic: assign static ip
Replies: 1
Views: 163

Re: assign static ip

OK so I assume from what you have said you are running a dhcp server (ihc-dhcp-server?) to assign the IP address to the 'client' machines that you want to always have the same IP address assigned. In which case you would edit /etc/dhcpd.conf and add the following lines (iirc there is an example alre...
by RattusRattus
Mon Sep 23, 2019 2:20 pm
Forum: Troubleshooting
Topic: Just a question? Reformatting an HD
Replies: 9
Views: 548

Re: Just a question?

Assuming that you don't need the data on it 1) erase the disk (puts it in a state windows will be happy with) sudo dd if=/dev/zero of=/dev/sd?? bs=4M (replace sd?? with the device node for the hard disk you are wanting to reformat) 2) boot windows - windows will see a blank disk and allow you to for...
by RattusRattus
Mon Sep 23, 2019 2:16 pm
Forum: Beginners
Topic: Network Mapping a Harddrive
Replies: 1
Views: 134

Re: Network Mapping a Harddrive

As you are using Ubuntu then I would suggest that you use NFS.
the following tutorial should help:

https://pimylifeup.com/raspberry-pi-nfs/

BR
/Andy
by RattusRattus
Mon Sep 23, 2019 2:07 pm
Forum: Beginners
Topic: LTE
Replies: 3
Views: 277

Re: LTE

the first hit I got on google for "lte modem raspberry pi" is this

https://filippobuletto.github.io/home-router-lte/

This looks like a walk though for what you would need and how to do it

BR
/Andy
by RattusRattus
Sun Sep 22, 2019 7:02 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Failed SPI Loopback Test
Replies: 19
Views: 2349

Re: Failed SPI Loopback Test

Have you enabled SPI / loaded the device driver?

https://www.raspberrypi.org/documentati ... /README.md

/Rattus
by RattusRattus
Fri Sep 20, 2019 3:46 pm
Forum: General discussion
Topic: headless setting up
Replies: 11
Views: 994

Re: headless setting up

Hi there, If you can see the Pi connecting to your Hotspot I guess you can see the IP address it is being given by the hotsport. I guess that you are also connecting to the same hotspot with your windows PC? if so simply open putty on yoiur windows PC and enter the IP address that has been given to ...
by RattusRattus
Fri Sep 20, 2019 3:41 pm
Forum: Automation, sensing and robotics
Topic: Liquid volume sensor in a tank
Replies: 11
Views: 3004

Re: Liquid volume sensor in a tank

a good start point could be here, but as previously stated there are MANY projects along this line...

https://thepihut.com/blogs/raspberry-pi ... spberry-pi

/Andy
by RattusRattus
Wed Sep 18, 2019 6:27 pm
Forum: Beginners
Topic: SPI on Raspberry Pi. "Translating" from C to python.
Replies: 2
Views: 414

Re: SPI on Raspberry Pi. "Translating" from C to python.

I would statrt with a turorial like https://learn.sparkfun.com/tutorials/ra ... torial/all
in in particular take a close look at SPIdev https://pypi.org/project/spidev/

Hope this helps

/Andy
by RattusRattus
Wed Sep 18, 2019 8:57 am
Forum: Automation, sensing and robotics
Topic: Liquid volume sensor in a tank
Replies: 11
Views: 3004

Re: Liquid volume sensor in a tank

Hi there. There are several methods this can be done. Traditionally tanks had sensor probes that contained float switches. You would have a different switch at a different depth - easy. However it does not tell you how much 'stuff you have in your tank' For a liquid in a tank pressure sensors are us...
by RattusRattus
Wed Sep 18, 2019 8:37 am
Forum: Beginners
Topic: [SOLVED]How to set up dhcp IP from file similar to setting up Static IP in dhcpcd.conf
Replies: 6
Views: 528

Re: How to set up dhcp IP from file similar to setting up Static IP in dhcpcd.conf

Hi there setting an IP address can be done 2 ways ether static or dynamically if you are setting your IP statically then this is done on your local machine and that would be a setting in /etc/networks If you want dynamic allocation there are several ways to obtain an IP address traditionally (and my...
by RattusRattus
Wed Sep 18, 2019 8:06 am
Forum: Python
Topic: Change in logic in sensor not breaking 'while' loop?
Replies: 3
Views: 380

Re: Change in logic in sensor not breaking 'while' loop?

Have you confirmed that you can read from the sensor at all? For now I would ignore your motor control and just write a bit of code to show you that the sensor is working as you would expect. I would also use a multimeter to check if the line does go to a logic 1 (in this case 3.3V) and then go to l...
by RattusRattus
Wed Sep 18, 2019 7:49 am
Forum: Automation, sensing and robotics
Topic: Automation system from Internet via Pi
Replies: 4
Views: 627

Re: Automation system from Internet via Pi

You are talking about controlling the hardware on the RPi vi\ a remote website. May I make a recommendation decouple, Decouple, DECOUPLE :-) Split your programs into a modular system. Have all your RPi hardware contol and feedback simply talk to a file on your RPi (this could be a RAMDisk in /dev/sh...

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