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by MarkTF
Wed May 09, 2018 4:34 pm
Forum: General discussion
Topic: Flame Sensor
Replies: 11
Views: 1246

Re: Flame Sensor

"https://www.sunfounder.com/learn/lesson-27-flame-sensor-sensor-kit-v1-for-arduino.html" Although it says Arduino, I'm sure it can be used for the Raspberry Pi can't it? Yes it can. Two things to keep in mind are that the Raspberry Pi (RPi) is a 3.3 V device and it does not have a built-in analog t...
by MarkTF
Wed May 09, 2018 1:56 pm
Forum: General discussion
Topic: Flame Sensor
Replies: 11
Views: 1246

Re: Flame Sensor

You don't mention what flame sensor you're using. I've posted the schematic for one variant below: https://www.sunfounder.com/media/wysiwyg/swatches/sensor_kit_v2_0_for_b_plus/lesson-21-flame-sensor/fdsfassa.png 1) Wire (either directly or via a breakout board) Vcc to 3.3 V on the RPi, GND to GND on...
by MarkTF
Tue May 08, 2018 1:10 pm
Forum: Advanced users
Topic: [SOLVED] Shutdown - when shutting down
Replies: 10
Views: 1154

Re: Shutdown - when shutting down

/sbin/shutdown, reboot etc are compiled binaries. I think you would have to get the source code(s), modify it, then recompile. One can move or rename any compiled binary and put a script in its place to perform some action prior to calling the original binary. Also, while I don't have access to a R...
by MarkTF
Mon May 07, 2018 1:02 pm
Forum: General discussion
Topic: What constitutes "Advanced"
Replies: 18
Views: 1323

Re: What constitutes "Advanced"

joan wrote:
Mon May 07, 2018 12:41 pm
Slightly more seriously, it probably doesn't matter much where a question is posted, I suspect 99% of the answered posts are from users who use the "New posts" button.
If I just now discovered that a "New posts" button exists, am I now an "Advanced user"?
by MarkTF
Mon May 07, 2018 12:58 pm
Forum: General discussion
Topic: VNC viewer - problem login into remote Pi
Replies: 1
Views: 235

Re: VNC viewer - problem login into remote Pi

"vncpasswd" from a ssh terminal session or directly on the Pi will prompt for a VNC password change
by MarkTF
Sun May 06, 2018 9:30 pm
Forum: General discussion
Topic: Determine if ceiling fan is moving from 2 or 3 meters away?
Replies: 5
Views: 584

Re: Determine if ceiling fan is moving from 2 or 3 meters away?

Using parts I had at hand, I tried a couple things. For what it's worth I did this with an Arduino Uno rather than a RPi, because the prototype codes are common example code and the second approach requires an analog converter. First was to use an HC-SR04 ultrasonic, which is one I understand to be ...
by MarkTF
Thu May 03, 2018 7:29 pm
Forum: Advanced users
Topic: Life of Pi? Is 24/7 use better than on-off switching?
Replies: 14
Views: 1617

Re: Life of Pi? Is 24/7 use better than on-off switching?

If this is a solar powered application, I would think minimizing power consumption would typically be more important than any concern about longevity at the margins. The main concern with power cycling is thermal cycling which puts strain on connections (ball grid arrays in particular) as the compon...
by MarkTF
Tue May 01, 2018 8:31 pm
Forum: General discussion
Topic: Edit for timelapse fourm
Replies: 3
Views: 261

Re: Edit for timelapse fourm

Assuming a Pi with WiFi, you could configure the Pi as a WiFi access point, use a laptop or mobile phone to log onto that network, and follow previous suggestions. Similarly you could connect a laptop to Pi via point to point ethernet or USB serial. Alternately you could write a script that starts a...
by MarkTF
Tue May 01, 2018 4:43 pm
Forum: General discussion
Topic: Bad power connector on Pi Zero W & buying in bulk
Replies: 37
Views: 2130

Re: Bad power connector on Pi Zero W & buying in bulk

. . . The issue is, the connector doesn't seem loose to the board, that I can tell, but the internals of the connector seem to be defective. . . . If you are modestly competent with a soldering iron, it is probably worth putting some flux on the USB connector pads and reflowing the solder as this i...
by MarkTF
Mon Apr 30, 2018 1:45 pm
Forum: General discussion
Topic: Hello, a quick question of timelapse
Replies: 2
Views: 210

Re: Hello, a quick question of timelapse

Coincidentally, I set up a timelapse node over the weekend in order to record a plant sprouting. My approach was to use a vncserver to remote the desktop to another computer. I used python/pygame to do single frame photo capture and store and will ultimately use ffmpeg to combine the stills into a v...
by MarkTF
Thu Apr 26, 2018 9:29 pm
Forum: General discussion
Topic: Serial terminal apps for RPI
Replies: 4
Views: 3668

Re: Serial terminal apps for RPI

"LXterminal" is the Linux command terminal within LXDE based systems like Raspbian, it isn't a serial terminal. "Minicom" is a text-based terminal emulator that one would run from the LXterminal command line "Screen" is another text-based terminal, perhaps a bit less user friendly than minicom in th...
by MarkTF
Tue Apr 24, 2018 1:35 pm
Forum: General discussion
Topic: Are Raspberry Pi and other microcontrollers scalable for commercial projects?
Replies: 13
Views: 1138

Re: Are Raspberry Pi and other microcontrollers scalable for commercial projects?

According to their github, the Airfy Beacon uses a Nordic Semiconductor nRF51822 ARM M0 with BLE SOC. There exists an Arduino-compatible development board and core for a device in this microcontroller family, but I'm guessing that's not the development path Airfy took. Rather it looks like they did ...
by MarkTF
Mon Apr 09, 2018 12:48 pm
Forum: General discussion
Topic: Raspberry Pi live graphs
Replies: 4
Views: 1198

Re: Raspberry Pi live graphs

Matplotlib on a RPi is capable of refreshing a plot at a rate of several frames per second. This requires careful use of the matplotlib library functions so that the Pi is not asked to recompute static parts of the graph each frame and only has to update the data driven bits. If you were to show you...
by MarkTF
Fri Mar 02, 2018 2:50 pm
Forum: Advanced users
Topic: ADS1115: How to interpret neg, 0 and pos values?
Replies: 4
Views: 704

Re: ADS1115: How to interpret neg, 0 and pos values?

I don't need precise sound measurement. Can I use it as a sound intensity checker instead? If you're not trying to reproduce the sound, it might be ok to under sample. You'd have to take a number of samples and look for a peak over the sample set, which is what one would do in any case. Looking at ...
by MarkTF
Thu Mar 01, 2018 1:58 pm
Forum: Advanced users
Topic: ADS1115: How to interpret neg, 0 and pos values?
Replies: 4
Views: 704

Re: ADS1115: How to interpret neg, 0 and pos values?

How can I make sense of the values I read from the ads1115? I'll be using it for a sound sensor. Numeric representation issues aside, the ADS1115 isn't appropriate for use as "a sound sensor". It has a low maximum sampling rate (860 samples per second (SPS)). An audio A/D should have a sample rate ...
by MarkTF
Wed Feb 28, 2018 2:35 pm
Forum: General discussion
Topic: Telemetry
Replies: 3
Views: 581

Re: Telemetry

Some other possibilities include USB attached devices. I've used USB sound cards, which works well for audio frequencies (duh!) but typically doesn't work at DC or above 20 kHz. I've also used USB attached microcontroller boards (Arduino or similar) for data acquisition. This adds a layer of complex...
by MarkTF
Mon Feb 05, 2018 1:58 pm
Forum: General discussion
Topic: Safe Use of RESET on Pi Zero
Replies: 7
Views: 1868

Re: Safe Use of RESET on Pi Zero

As others have noted above, the safe approach is to shutdown the system on the software side to ensure that all write operations to SD are completed before resetting the machine. If one is using Reset (or powering down) a machine that has not been properly shutdown, there is risk of disk corruption....
by MarkTF
Fri Feb 02, 2018 7:20 pm
Forum: Advanced users
Topic: Reset Raspberry Pi from Arduino
Replies: 24
Views: 5434

Re: Reset Raspberry Pi from Arduino

I've Arduino Pro Mini (5V) version. I'd like to use one of the available pin of Arduino to hard reset Raspberry. What would be most conevenient way to do it from Arduino? I have a bunch of resistors and leds I could use. The issue is that your Arduino wants to output 5V as a logic high which exceed...
by MarkTF
Mon Jan 29, 2018 3:28 pm
Forum: General discussion
Topic: How many sensors/leds I can put on the breadboard?
Replies: 14
Views: 1978

Re: How many sensors/leds I can put on the breadboard?

Currently, I have a wb-102 breadboard. But will expand to many little breadboards once the project expands. What would be the best way to calculate how much the current take together (each sensor) so I would know if I need an external power source. Looking at the datasheet for each sensor of intere...
by MarkTF
Wed Jan 17, 2018 10:39 pm
Forum: Advanced users
Topic: Zero w alternative power source
Replies: 9
Views: 1276

Re: Zero w alternative power source

Gavinmc42 wrote:
Tue Jan 16, 2018 1:48 am
I have yet to try it but Zero's can be powered direct from a LiPo.
How so? Do you mean directly attaching a LiPo the "+3V3 OUT" pins bypassing a regulator or do you mean a LiPo to the "+5V" pins?
by MarkTF
Fri Dec 22, 2017 8:16 pm
Forum: General discussion
Topic: SD Card replacement with on-board memory ?
Replies: 24
Views: 5969

Re: SD Card replacement with on-board memory ?

. . . I came even to the point (I regret to say) that I am starting with the Onion Omega2+, to see if that works better. . . . The Onion Omega2+ boots (OpenWRT) from flash then runs out of RAM so unless you're logging a large amount of data there shouldn't be flash endurance problems with it. If yo...
by MarkTF
Fri Dec 22, 2017 5:45 pm
Forum: General discussion
Topic: Warrenty of the Pi ?
Replies: 63
Views: 5536

Re: Warrenty of the Pi ?

1) I've used these pins without issue. In the niche of people doing external watch dog stuff, it's probably the norm to use these pins. 2) You probably want to check your soldering station to verify that it is ESD safe, your are using good soldering technique, and that whatever circuitry you are at...
by MarkTF
Fri Dec 22, 2017 3:21 pm
Forum: General discussion
Topic: Warrenty of the Pi ?
Replies: 63
Views: 5536

Re: Warrenty of the Pi ?

1) I've used these pins without issue. In the niche of people doing external watch dog stuff, it's probably the norm to use these pins. 2) You probably want to check your soldering station to verify that it is ESD safe, your are using good soldering technique, and that whatever circuitry you are att...
by MarkTF
Thu Dec 21, 2017 4:41 pm
Forum: General discussion
Topic: Looking for a small monochrome display.
Replies: 9
Views: 1804

Re: Looking for a small monochrome display.

Maxwell175 wrote:
Thu Dec 21, 2017 2:36 pm
Is the one I mentioned above going to work? I would love some code samples or something.
From Adafruit, one of the official Raspberry Pi distributors: https://cdn-learn.adafruit.com/download ... rry-pi.pdf

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