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by mikronauts
Fri Nov 02, 2018 12:22 pm
Forum: General discussion
Topic: A good battery for the Pi 3B+?
Replies: 40
Views: 1013

Re: A good battery for the Pi 3B+?

Sorry, I meant not pi3b+'s ... I inadvertantly left out the '+' I am still waiting for pi3a or pi3a+ boards. (Typos mostly due to using a tzblet to post, as I am away from my office) Fyi, I run Pi3's (not 3b) off usb power banks all the time, so I see no reason a 3b would not run off a good power ba...
by mikronauts
Fri Nov 02, 2018 3:21 am
Forum: General discussion
Topic: A good battery for the Pi 3B+?
Replies: 40
Views: 1013

Re: A good battery for the Pi 3B+?

Fyi, I run Pi3's (not 3b) off usb power banks all the time, so I see no reason a 3b would not run off a good power bank. I will try it soon, I need to test a 3b based robopi bog anyway. A regular phone charger battery pack will do what you want, but the hard part is finding one that actually holds i...
by mikronauts
Thu Nov 01, 2018 5:38 pm
Forum: Automation, sensing and robotics
Topic: [Help] - Arduino to Pi project
Replies: 3
Views: 151

Re: [Help] - Arduino to Pi project

Try serial comm to the arduino, and possibly Pygame for the hmi on the Pi. Hi, I'm new on this forum, and want to thanks you all in advice for all the help (and patinece). Just for let you know about my grade of knowledge, I tell you that I'm an automation engineer, working mostly on programming PLC...
by mikronauts
Tue Oct 23, 2018 5:05 pm
Forum: General discussion
Topic: Oh damn, it's happened! Charging a lot of pis?
Replies: 10
Views: 573

Re: Oh damn, it's happened! Charging a lot of pis?

I would use atx power supplies, 5v directly, and 12v regulated down to 5v. I’m actually kitted out quite well with variable power supplies, oscilloscopes, soldering kit and all sorts of magical electrical gubbins, but most of my electrical knowledge is invested in the world of high powered electric ...
by mikronauts
Mon Oct 22, 2018 3:17 pm
Forum: Automation, sensing and robotics
Topic: Connecting Pi to reed switches on long cable
Replies: 10
Views: 683

Re: Connecting Pi to reed switches on long cable

Not likely (at least not reliably) Use a transistor (or mosfet or ssr) to switch 12v, and an opto isolator to read it. To clarify, 12V is what the switches are designed for. I have no 12V in my system at present, all I have is a Pi, some cable and a reed switch. If I put 3.3V down 25m of wire, then ...
by mikronauts
Mon Oct 22, 2018 3:14 pm
Forum: Automation, sensing and robotics
Topic: Using RPI link with PLC
Replies: 2
Views: 416

Re: Using RPI link with PLC

Which plc?

Depending on supported protocol, it could be reasonably easy.

Think modbus/tcp, NOT OPC
robinshion wrote:
Sun Oct 21, 2018 11:42 pm
Does anyone have an idea about using RPI ethernet port link to PLC ethernet port, that act as OPC or something else to get data collection?
by mikronauts
Thu Oct 11, 2018 5:54 pm
Forum: Beginners
Topic: ADC in python, change sampling time
Replies: 2
Views: 91

Re: ADC in python, change sampling time

you will get a lot of variance if you leave the input floating

Tie unused inputs to ground.
by mikronauts
Thu Oct 04, 2018 2:30 pm
Forum: Automation, sensing and robotics
Topic: Experience with robot-core controller?
Replies: 1
Views: 155

Re: Experience with robot-core controller?

I am not familiar with that interesting board ... I like its dc-dc converter (I use off-board converters or BEC's) Depending on your applications you may wish to take a look at http://www.mikronauts.com/raspberry-pi/pi-droid-alpha/ (10 bit 8 ch adc, L293d motor driver, servo control) http://www.mikr...
by mikronauts
Wed Sep 26, 2018 10:36 pm
Forum: General discussion
Topic: Unable to read adc data from SPI0 bus in raspberry pi 3
Replies: 10
Views: 302

Re: Unable to read adc data from SPI0 bus in raspberry pi 3

Take a peek at my article at http://www.mikronauts.com/raspberry-pi/raspberry-pi-analog-to-digital-conversion-experiments-and-howto/ It does need an external 3:8 demux, but it allows you to use just one of the SPI /CS signals and decode to eight SPI peripherals by using three GPIO's to decide which ...
by mikronauts
Wed Sep 05, 2018 5:02 pm
Forum: Beginners
Topic: Completely new to Raspberry Pi. Need to build logger for work.
Replies: 21
Views: 716

Re: Completely new to Raspberry Pi. Need to build logger for work.

Google "raspberry pi data logging", you will find a lot of helpful information. Other questions you may have to consider: what does it log to: serial output, network, display, …? are these existing sensors, or a new build? Interfacing to some older sensors can be challenging, and you may need specia...
by mikronauts
Tue Sep 04, 2018 2:54 am
Forum: General discussion
Topic: HC-SR04 Ultrasonic directly on PI 3
Replies: 3
Views: 128

Re: HC-SR04 Ultrasonic directly on PI 3

No.

The 5v output of the echo pin would likely damage thr 3.3v pi gpio
lucandmendes wrote:
Tue Sep 04, 2018 2:13 am
Hi, just a simple question:
Can I plug HC-SR04 Ultrasonic directly on gpio without any resistor ?(Just plug the wires to work)

Thank you!!
by mikronauts
Sat Aug 25, 2018 3:00 pm
Forum: General discussion
Topic: Interface o serial port to raspberry 3B
Replies: 1
Views: 38

Re: Interface o serial port to raspberry 3B

Easiest solution is a usb to serisl adapter Hello, I am working on a project in which from the serial port of a precision scale the output will go to the usb port of the Pi. I have to get the reading and display on to a 7 inch touch screen. The hardware is procured and I am writing the code in Pytho...
by mikronauts
Fri Aug 24, 2018 6:30 pm
Forum: Python
Topic: Convert video to bit stream
Replies: 18
Views: 528

Re: Convert video to bit stream

Sorry, it won't work - unless you choose a really really low resolution greyscale video. The GPIO is not fast enough. Simple calculation for 320x240 8 bit greyscale (256 shades): 60fps * 320 * 240 = 4,608,000 bytes per second Call it 5MBytes after adding sync info (note this does not include any aud...
by mikronauts
Sat Aug 18, 2018 3:10 pm
Forum: Advanced users
Topic: Floating input on industrial usage
Replies: 9
Views: 420

Re: Floating input on industrial usage

My bad, I misread the second figure as vonnecting the 24v direcly using just a current limiting resistor. ..use a proper voltage divider instead of just a 10k resistor (may damage Pi with just that resistot) Not so. The only voltages on the RPi side of the opto are ground and 3.3 volts. 3.3 volts is...
by mikronauts
Fri Aug 17, 2018 11:19 pm
Forum: Advanced users
Topic: Floating input on industrial usage
Replies: 9
Views: 420

Re: Floating input on industrial usage

The opto isolator circuit needs to connect to the ground of the 24v signal (not the Pi) to the cathode of its led, and 1k8 may be too low a value (i did not check you devices data sheet) The non isolated circuit would neef to connect the Pi and machine grounds and use a proper voltage divider instea...
by mikronauts
Fri Aug 17, 2018 11:11 pm
Forum: Automation, sensing and robotics
Topic: Multiple inputs and outputs.
Replies: 4
Views: 260

Re: Multiple inputs and outputs.

Heater is right, the Propeller is fantastic for driving servos, pwm, etc. So much so that I designed a robotics controller for the Pi based on a propeller, with an 8 channel 12 bit 0..5v adc as well. Please see http://www.mikronauts.com/raspberry-pi/robopi/ There are some sample bots in my articles ...
by mikronauts
Tue Aug 14, 2018 4:44 pm
Forum: Beginners
Topic: Reading a few sensors in the same time (Python)
Replies: 3
Views: 169

Re: Reading a few sensors in the same time (Python)

You could connect one f the adafruit uart based sensors to the pi uart As for the i2c adc you will have to poll its inputs one at a time, and you sample rate will be limited by i2c speeds... so don't expect thousands of samples per second for multiple channels I have a few sensors connected to RPI 3...
by mikronauts
Tue Aug 14, 2018 2:11 am
Forum: General discussion
Topic: pi zero w in quantities of 10...50
Replies: 72
Views: 9883

Re: pi zero w in quantities of 10...50

Fyi, it is still 1 per customer. Too bad, I designed a really nice smt robot controller board for the 0w months ago same size as the 0), but with restricted 0w sales it is not viable to take to production. Why is Adafruit still restricting the Pi0WH to one per order? I thought that one was not suppo...
by mikronauts
Tue Aug 14, 2018 1:27 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Raspberry Pi Data Acquisition & SPI Multiplexing (howto)
Replies: 7
Views: 2426

Re: Raspberry Pi Data Acquisition & SPI Multiplexing (howto)

Hi, I just got my site back up (long story, almost year long project kept me from Pi projects, then I was hacked multiple times ... just got back to my office today and fixed my site) Re/ your question... perhaps wiring issue? Or spi not enabled? Hello Mikronauts, I am trying to do something similar...
by mikronauts
Sat Nov 25, 2017 4:43 pm
Forum: HATs and other add-ons
Topic: Anybody interested in talking direct! to IDE/SATA?
Replies: 28
Views: 4652

Re: Anybody interested in talking direct! to IDE/SATA?

We did some I/O test on the pi many, many years ago. (My god, I am getting old...) At 100 MHz the signal looked more like a sine wave. So my guess is that 50-75 MHz is about the limit. At 16 bits wide that is 100-150 Mbyte/sec. 100MB-150MB/sec would still be sweet :) At the time I wrote that code, ...
by mikronauts
Wed Nov 22, 2017 12:52 am
Forum: HATs and other add-ons
Topic: Anybody interested in talking direct! to IDE/SATA?
Replies: 28
Views: 4652

Re: Anybody interested in talking direct! to IDE/SATA?

Hi Gert, Well done! 44MBytes/sec over a channel independent from USB is a nice achievement. I was looking into doing the same thing, and have been trying to get actual register level documentation from RPF, Broadcom reps etc - no joy. A couple of kind RPF employees pointed me at the NAND kernel driv...
by mikronauts
Mon Aug 28, 2017 10:36 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI or BitBang via GPIO to 5v device and vice-versa
Replies: 45
Views: 6218

Re: SPI or BitBang via GPIO to 5v device and vice-versa

it's not the feeding

it is the responding witin 1us

google:

hard real time

6502 bus cycle documentation
by mikronauts
Mon Aug 28, 2017 7:04 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI or BitBang via GPIO to 5v device and vice-versa
Replies: 45
Views: 6218

Re: SPI or BitBang via GPIO to 5v device and vice-versa

You cannot get a guaranteed 1us response from a pi like that. Not even 2us (as I recall that 500khz was the maximum respone rate) Add an fpga or dual ported memory between the apple bus and a pi (if you need to use a Pi) Thanks for replying! What I'm looking for is to implement a peripheral card on ...
by mikronauts
Mon Aug 28, 2017 6:39 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI or BitBang via GPIO to 5v device and vice-versa
Replies: 45
Views: 6218

Re: SPI or BitBang via GPIO to 5v device and vice-versa

Hi, Sorry, basically impossible as asked... but it really depends on exactly what you are trying to do. 1) pi emulating ram for a 6502 ... impossible without a big fpga that has enough block ram and level shifters and this case the fpga emulates the memory, which the pi could also access 2) run appl...

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