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by mark3112
Tue May 15, 2018 2:46 pm
Forum: Beginners
Topic: Changing PIGPIO SPI timing
Replies: 2
Views: 550

Re: Changing PIGPIO SPI timing

Have you tried both SCLK modes in spiFlags as clocking the data on the wrong edge will cause odd data.
Otherwise info on the device and your code would be helpful.
by mark3112
Tue May 15, 2018 12:52 pm
Forum: Raspberry Pi OS
Topic: 3B+ dhclient eth0 problem
Replies: 0
Views: 353

3B+ dhclient eth0 problem

Hi I am running 2018-04-18-raspbian-stretch-lite on a 3B and 3B+ I need to Spoof the MAC Address so use the commands below. On the 3B it works as it always has. On the 3B+ the last command either responds with Too few Arguments or just hangs. Is there some additional argument required by the 3B+? su...
by mark3112
Sat May 12, 2018 10:23 pm
Forum: Off topic discussion
Topic: Connecting and send Data from a FPGA to the Raspberry
Replies: 2
Views: 3352

Re: Connecting and send Data from a FPGA to the Raspberry

SPI.
I use an FPGA as the master, communicating a STM32F432.
But as the Pi has to be the master then you are somehow going to have to set the Pi to initiate the transfer. But its do’able.
by mark3112
Sat May 12, 2018 9:30 pm
Forum: General discussion
Topic: Communication between multiple RPI installations in Home Automation System
Replies: 3
Views: 999

Re: Communication between multiple RPI installations in Home Automation System

I’m have a Home Automation System and am lucky in having it sponsored by my employer as I work in their R&D dept. The way I see it, having the Control Elements is one thing, controlling the mains power to the end points, is another. I see you refer to relays but to me that’s way too digital. How...
by mark3112
Sat May 12, 2018 8:42 pm
Forum: General discussion
Topic: Effective way to communicate Raspberry Pi with STM32
Replies: 13
Views: 12877

Re: Effective way to communicate Raspberry Pi with STM32

If they are close together, just use I2C, SPI or RS-232.
by mark3112
Fri May 11, 2018 8:23 pm
Forum: General discussion
Topic: Effective way to communicate Raspberry Pi with STM32
Replies: 13
Views: 12877

Re: Effective way to communicate Raspberry Pi with STM32

CAN could be an option or RS-485.
The STMF4xx range normally have two CAN Controllers built in, so would only need an Interface Chip (see MCP2551 as an example) and the pi end could use the MCP2515 on an SPI port (and another Interface Chip).

https://en.wikipedia.org/wiki/CAN_bus
by mark3112
Thu May 10, 2018 6:38 pm
Forum: Beginners
Topic: Raspberry Pi ventilation diagram suggestions are welcome
Replies: 1
Views: 357

Re: Raspberry Pi ventilation diagram suggestions are welcome

I think the vent pipes being at such a low level is going to trap the heat in the upper part of the enclosure.
How about:
by mark3112
Wed May 09, 2018 10:41 am
Forum: Beginners
Topic: 7 segment LED
Replies: 5
Views: 1301

Re: 7 segment LED

Hi Sorry, never used Python so can’t help with that, but there are plenty of examples here. https://www.raspberrypi.org/forums/viewtopic.php?t=173781 Address for the I2C device (as wired in diagram) is 0x22, see pins A0,A1,A2 (could have up to 8 devices at address 0x20-0x27). To set the chips mode t...
by mark3112
Tue May 08, 2018 6:30 pm
Forum: Off topic discussion
Topic: How do you detect that your kids are nerds
Replies: 6
Views: 2565

Re: How do you detect that your kids are nerds

Nah.
Kid: sudo Give me a chocolate candy (NOW)!
by mark3112
Tue May 08, 2018 6:11 pm
Forum: Beginners
Topic: 7 segment LED
Replies: 5
Views: 1301

Re: 7 segment LED

Maybe not exactly suitable for a beginner, but here’s an option. Instead of using GPIO pins, how about using I2C? The HDSP-523E device is a dual 7 segment display, which meets one of your criteria, and the MCP23017 can handle it using only 2 GPIO pins. I (along with many on here) can supply the code...
by mark3112
Fri May 04, 2018 12:46 pm
Forum: Other projects
Topic: control solenoid using raspberry pi
Replies: 5
Views: 1132

Re: control solenoid using raspberry pi

Personally I like to limit direct connections to low current electronics. For anything else I prefer to isolate the Pi from the hardware. In the circuit below the opto is quite expensive (as these parts go £0.80) but only needs 1mA and protects the pi from the occasional mistake.
OPTO.PNG
OPTO.PNG (6.2 KiB) Viewed 1045 times
by mark3112
Fri May 04, 2018 12:26 pm
Forum: Troubleshooting
Topic: Changing the MAC address on a Pi 3B+
Replies: 7
Views: 5262

Re: Changing the MAC address on a Pi 3B+

A problem I hit when spoofing the MAC Address on a 3B was the Pi would register with the DHCP server using its ‘proper’ MAC and then re register with the Spoofed address. As I didn’t want the original MAC Address showing up, here is what I do. In /etc/network/interfaces – Add (Incomplete info so doe...
by mark3112
Wed May 02, 2018 5:34 pm
Forum: Automation, sensing and robotics
Topic: Autonomous Drone Boat
Replies: 4
Views: 1672

Re: Autonomous Drone Boat

I could be interested if it’s not an Angler cheating device. About 15 years ago I modified a friend’s RC bait boat and then got caught up in an Angler arms race (although if you really need side scan sonar and GPS to catch fish, I think it’s gone way beyond a hobby). Can do hardware, programming and...
by mark3112
Thu Apr 26, 2018 7:35 pm
Forum: Beginners
Topic: Cheapest possible off-grid GSM CCTV
Replies: 12
Views: 4179

Re: Cheapest possible off-grid GSM CCTV

You don’t need to use a pi. There are camera’s that can detect motion, record it to a local SD Card and send notifications via the internet.

http://www.argos.co.uk/product/5699746

Not the best, but could do what you want.
I’m willing to help if I can.
by mark3112
Thu Apr 26, 2018 6:07 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI with C/D ?
Replies: 2
Views: 505

Re: SPI with C/D ?

MOSI – Master Out Slave In
MISO – Master In Slave Out
Depends on who’s Master and who’s Slave.
Using a pi, thats the master, and your TFT is the Slave, unless there is a pi slave option I'm not aware of.
by mark3112
Wed Apr 25, 2018 7:04 pm
Forum: Raspberry Pi OS
Topic: Change DHCP Server timeout value?
Replies: 0
Views: 425

Change DHCP Server timeout value?

I’m using a pi in a device that may not have an Ethernet connection. Currently I am shipping them with Eth0 disabled as if the DHCP server isn’t available, the pi waits about 90 seconds at ‘Starting Hostname Service’ before continuing the boot. Is there a way of reducing the time the pi waits for th...
by mark3112
Wed Apr 25, 2018 1:09 pm
Forum: Automation, sensing and robotics
Topic: Power Supply for 24V vehicle
Replies: 2
Views: 1185

Re: Power Supply for 24V vehicle

Something I’m using that could handle the voltage and maybe even the noise. Input Voltage up to 42V Here is a link to an evaluation board based on the LM22670 but implies it can be used for the LM22676 (which is what I use) as well. https://www.mouser.co.uk/ProductDetail/Texas-Instruments/LM22670EVA...
by mark3112
Tue Apr 17, 2018 5:43 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Gpio simultaneous reading
Replies: 10
Views: 1419

Re: Gpio simultaneous reading

Without a strobe signal could it be that you are sampling a signal during its rise time? I’ve have had similar problems interfacing to FPGA’s. Probably the simplest solution is read the data twice if they don’t match throw the first sample away and read again until they match. Better still supply a ...
by mark3112
Thu Apr 12, 2018 6:07 pm
Forum: C/C++
Topic: pigpio SPI1 Init error
Replies: 3
Views: 1037

Re: pigpio SPI1 Init error

Update. I assumed that as the config wasn’t behaving as I expected that the SPI1 port wasn’t working. I stopped working on the pi code and turned my attention to the STM code at the other end of the SPI bus. Whilst testing the STM code I saw that it was receiving my SPI test message, so the pi’s SPI...
by mark3112
Mon Apr 09, 2018 7:46 pm
Forum: General discussion
Topic: STICKY: Introduce yourself!
Replies: 3887
Views: 302028

Re: STICKY: Introduce yourself!

Hello. Registered for some help with a SPI1 problem, can’t use SPI0 as that’s busy looking after 4 MCP2515 CAN Controllers. Want to use SPI1 to transfer CAN A/D and timing data from a STM32F4 board and display it on the Pi’s display. 1st computers - Commodore PET and Cromemco S100 system in college ...
by mark3112
Mon Apr 09, 2018 10:51 am
Forum: C/C++
Topic: pigpio SPI1 Init error
Replies: 3
Views: 1037

pigpio SPI1 Init error

Hi I am trying to use pigpio to enable SPI1 with CE0. I set up the SPI1 pins to their Alternate Function setting and set pin 17 (which would be CE1) low. After running the spiOpen command the Alternate function for CE0 has changed and the state of pin 17 changes to high. Any suggestions what I am do...

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