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by mikronauts
Thu Oct 11, 2018 5:54 pm
Forum: Beginners
Topic: ADC in python, change sampling time
Replies: 2
Views: 71

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: 78

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: 249

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: 688

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: 124

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: 34

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: 450

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: 401

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: 401

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: 242

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: 161

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: 9142

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: 2350

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: Add-ons
Topic: Anybody interested in talking direct! to IDE/SATA?
Replies: 28
Views: 3970

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: Add-ons
Topic: Anybody interested in talking direct! to IDE/SATA?
Replies: 28
Views: 3970

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: 6060

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: 6060

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: 6060

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...
by mikronauts
Sat Aug 19, 2017 10:55 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Pi0 - 2 USB devices without HUB
Replies: 4
Views: 838

Re: Pi0 - 2 USB devices without HUB

good point

I was taking the op's need for two usb devices at face vale.

I will now go and mske more coffee :)
Martin Frezman wrote:
Sat Aug 19, 2017 9:23 pm
Getting a hub would violate one of the premises.

Instead, get a Pi Zero W - which has wireless built-in. Then you don't need to have an external WiFi dongle.
by mikronauts
Sat Aug 19, 2017 9:15 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Pi0 - 2 USB devices without HUB
Replies: 4
Views: 838

Re: Pi0 - 2 USB devices without HUB

you need a new pi and add a hub
by mikronauts
Wed Aug 16, 2017 3:57 pm
Forum: Python
Topic: HC-SR04 always return 1.0
Replies: 4
Views: 917

Re: HC-SR04 always return 1.0

You can try my article/tutorial: http://www.mikronauts.com/raspberry-pi/gpio-experiments/raspberry-pi-and-hc-sr04-distance-sensor-interfacing-with-c-and-python/ Hi, I have trying to run the example in this tutorial: https://www.raspberrypi.org/learning/physical-computing-with-python/distance/ Howeve...
by mikronauts
Tue Aug 01, 2017 11:17 pm
Forum: Automation, sensing and robotics
Topic: Multiplexing Mabotix Ultrasonic Sensors with Pi
Replies: 5
Views: 1131

Re: Multiplexing Mabotix Ultrasonic Sensors with Pi

You are welcome. with 16 analog inputs, easiest way is to use two mcp3008 with ce0 to one ce1 to the other miso mosi sclk to both this assumes you do not need any more spi devices it is also now possible to use other gpio for chip selects with dt-overlay if you want to run the sensors at 5v, run the...
by mikronauts
Tue Aug 01, 2017 5:45 pm
Forum: General discussion
Topic: Raspi hat blocks all the gpio pins
Replies: 32
Views: 4817

Re: Raspi hat blocks all the gpio pins

As alphanumeric said, you can add a prototyping board with a stacking header between the Pi and the Hat.

Adafruit has such a prototyping board.

So does Mikronauts (working on uploading the product pages) basically a 40 pin gpio version of my EZasPi 26 pin boards :-)

Best Regards,

Bill
by mikronauts
Tue Aug 01, 2017 5:43 pm
Forum: Automation, sensing and robotics
Topic: ADXL 345 and duplicate readings
Replies: 7
Views: 1387

Re: ADXL 345

Perhaps the sensor has filtering limiting you to 20-30 updates per second?

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