Go to advanced search

by Paul Hutch
Thu Oct 18, 2018 3:03 pm
Forum: General discussion
Topic: In search of reliable FCC-certified USB Wi-Fi adapter with removable antenna
Replies: 21
Views: 1670

Re: In search of reliable FCC-certified USB Wi-Fi adapter with removable antenna

... If I were their competitor and I wanted to play dirty pool, it would be super easy. Just put in a report to the FCC that their adapter is causing interference and sit back and watch the fireworks. Big no-no, and quite a risky one at that. No need to say that it interferes, simply say it is not ...
by Paul Hutch
Thu Oct 18, 2018 2:27 pm
Forum: General discussion
Topic: Howto set partition to a specific size after installation rather than filling whole SD card
Replies: 3
Views: 320

Re: Howto set partition to a specific size after installation rather than filling whole SD card

I run Drew Bonasera's PiShrink script after creating a dd image to shrink the image a small as possible which allows putting it on a smaller uSD card. The script also adds the commands to re-size the partition to fill up the new card on reboot. https://github.com/Drewsif/PiShrink In addition to usin...
by Paul Hutch
Mon Oct 01, 2018 11:37 pm
Forum: General discussion
Topic: 5 volts 5 amps power supply on raspberry pi 3 model b+
Replies: 14
Views: 1459

Re: 5 volts 5 amps power supply on raspberry pi 3 model b+

I would suggest a ~2.5A fuse between the Pi and the PSU and at least 17AWG wire (so the fuse blows before the wire melts) A fuse is definitely a great idea. Wire melting (fusing) is not a concern as long as the wire is at least 34AWG copper, although it would get fire starting hot (used to do it on...
by Paul Hutch
Fri Sep 28, 2018 2:52 pm
Forum: General discussion
Topic: Recommended way to backup SD card image under Windows?
Replies: 7
Views: 681

Re: Recommended way to backup SD card image under Windows?

I use this other PiShrink and love it. I dd the image on a RasPi with a USB uSD card reader and USB HDD for storing the images. Then I run Drew's shell script which shrinks the image and adds code to auto-expand the file system on first boot.
https://github.com/Drewsif/PiShrink
by Paul Hutch
Thu Sep 27, 2018 6:02 pm
Forum: Python
Topic: Python 3.x as standard
Replies: 25
Views: 2535

Re: Python 3.x as standard

I would like to see a bitter GUI maker than tkinker, I am trying wxpython but am having installation problem on the RPi, but the output in the docs. looks professional. I started using Python only about a year ago and very quickly abandoned Tkinter and wxPython. I like PyQt best for writing cross p...
by Paul Hutch
Thu Sep 20, 2018 7:22 pm
Forum: Advanced users
Topic: batterry powered Pi in hot areas
Replies: 6
Views: 1094

Re: batterry powered Pi in hot areas

AFAIK there are no standard battery types that can be charged above about 45°C. NiMH, NiCad and LiPO all can be discharged at up to 60°C and there are some high temp NiMH & NiCad good for up to 70°C. If I was looking to solve this I think I'd probably just make sure the battery never gets charges wh...
by Paul Hutch
Thu Sep 20, 2018 1:24 pm
Forum: General discussion
Topic: Ethernet switch with 8 ports and PTP
Replies: 8
Views: 1037

Re: Ethernet switch with 8 ports and PTP

Assumptions I've made do to unclear question: PTP = Peer to Peer 100 Mbps Ethernet copper (I can't imagine anyone paying for 100M fiber) Extension board = Raspberry Pi Hat For that I don't know of any that are available. However for a 100Mbps peer to peer LAN containing a Pi you can use pretty much ...
by Paul Hutch
Mon Sep 17, 2018 3:14 pm
Forum: General discussion
Topic: MCP3008 readings
Replies: 163
Views: 8662

Re: MCP3008 readings

Change ACS712_VOffset to 2.57 into the scrip ACS712_VOffset = 2.57 But, I suspect that your multimeter is not exact to calculate the resistor. both 4k7 and 10K display the same value in 2 digits. Really need 3 digits. To verify if our calculation is correct you should use a voltmeter and measure wi...
by Paul Hutch
Fri Sep 14, 2018 5:54 pm
Forum: General discussion
Topic: MCP3008 readings
Replies: 163
Views: 8662

Re: MCP3008 readings

I did the experiment with 5 ohms 10 ohms and 20 ohms resistor with 5V at 2 A supply But the three resistor were burnt after few second For a 5V supply: 5 ohm load = 1A = 5 Watts 10 ohm load =0.5A = 2.5 Watts 20 ohm load = 0.25A = 1.25 Watts A rule of thumb I use is that the power rating for a load ...
by Paul Hutch
Tue Sep 11, 2018 3:55 pm
Forum: General discussion
Topic: Getting Live Voltage data from Pi 3B+
Replies: 8
Views: 472

Re: Getting Live Voltage data from Pi 3B+

I see, so the following setup would be what I am looking at? Charger -> Pi -> LM385 -> A2D -> Display Module The connections are more like: Charger +-> Pi power input +-> LM385 circuit -> A2D reference voltage input (constant V) +-> voltage divider -> A2D measurement voltage input (variable V) A2D ...
by Paul Hutch
Tue Sep 11, 2018 3:31 pm
Forum: General discussion
Topic: Commercial use and capability of Pi 3B+ for making BLE enabled industrial IoT gateway?
Replies: 10
Views: 2680

Re: Commercial use and capability of Pi 3B+ for making BLE enabled industrial IoT gateway?

If we make only enclosure for that board can we sell it in US with this already certified model? Thanks... If all you are doing is bundling items currently avaialable at retail in the USA with a custom mechanical housing, then you do not need any additional certification. For examples see Adafruit,...
by Paul Hutch
Tue Sep 11, 2018 2:04 pm
Forum: General discussion
Topic: Struggling to get an ADC working
Replies: 6
Views: 451

Re: Struggling to get an ADC working

i dont understand y doesn'the rpi3 have an ADC? Fairly straigh forward question, does anybody know why the rpi3 doesn't have an ADC. The rpi 3 board allows to communicate via UART, SPI, I2C even has 4 USB ports, and many other ubiquitous features. Yet, it doesn't have an ADC, which I guess would co...
by Paul Hutch
Sat Sep 08, 2018 4:21 pm
Forum: General discussion
Topic: MCP3008 readings
Replies: 163
Views: 8662

Re: MCP3008 readings

Like I told you before, your sensor is working just fine . Your sensor can measure +/- 30A. So, effectieve it can measure 60A and you want to measure a current of 0.0025A (5/2000). That is roughly 0.0042% of what the sensor can measure. This means that the output voltage will change: 0.0025 * 66mV ...
by Paul Hutch
Sat Sep 08, 2018 1:24 pm
Forum: General discussion
Topic: MCP3008 readings
Replies: 163
Views: 8662

Re: MCP3008 readings

I am measuring output of acs sensor with multimeter. input voltage is 5v DC. and the output of acs is 2.5 V If I connect 10 K load and measure output voltage of acs it gives 2.5 V I think if i connect load at output, voltage of ACS should be change but It doesn't happen in my case I have been check...
by Paul Hutch
Tue Aug 28, 2018 2:31 pm
Forum: Advanced users
Topic: Unsolder wi-fi chip and antenna in RPI3
Replies: 47
Views: 3936

Re: Unsolder wi-fi chip and antenna in RPI3

It seems unlikely that removing the power and antenna from the WiFi chip while leaving the data and other circuits connected would increase electromagnetic interference. While it seems unlikely, so do many other unintentional radiation problems. I've had a 4" PCB trace and 2N3904 cause a problem in...
by Paul Hutch
Sat Aug 25, 2018 1:08 pm
Forum: General discussion
Topic: Wirelessly charged Rpi Zero?
Replies: 14
Views: 1445

Re: Wirelessly charged Rpi Zero?

With an autonomous robot a that parks itself to charge, it is very easy to have the robot slide into a dock where Pogo pins, or other low force connectors, can provide bucket loads of power with near zero losses.
by Paul Hutch
Wed Aug 22, 2018 5:16 pm
Forum: General discussion
Topic: WHITE SCREEN LCD
Replies: 2
Views: 279

Re: WHITE SCREEN LCD

I just hit what I think is the same problem yesterday when I finally tried out a 5" HDMI display I bought from Adafruit a while ago (it's for a future project but saw it and decided I better check that it actually works). I plugged it in and it was all white then had streaks but no usable display. W...
by Paul Hutch
Wed Aug 22, 2018 5:08 pm
Forum: General discussion
Topic: Need help - pi power
Replies: 3
Views: 316

Re: Need help - pi power

Based on the data at your link I'd use the USB Hi Smart Output which will only provide 5V/2.4A. The USB QC3.0 Output should default to 5V/3A when you connect a RasPi, as pointed out by W. H. Heydt, but since it's extremely unlikely you'll ever need more that 2.4A I'd stick with using the port that c...
by Paul Hutch
Wed Aug 22, 2018 3:00 pm
Forum: Advanced users
Topic: Resize image for use on a smaller sd card
Replies: 34
Views: 96138

Re: Resize image for use on a smaller sd card

I find the simplicity of a whole image backup much more convenient, although inefficient with processor time and storage space. First time preparation, copy the PiShrink script to the Raspberry Pi you will use for making the copies. https://github.com/Drewsif/PiShrink Backup: Place uSD card in reade...
by Paul Hutch
Mon Aug 20, 2018 3:05 pm
Forum: Advanced users
Topic: [RTC] DS3231 clock calibration (doubts and trouble)
Replies: 4
Views: 775

Re: [RTC] DS3231 clock calibration (doubts and trouble)

There appear to be more counterfeit, decades old stock, and recycled DS3231's on the market now than new units. The chip alone sells for $4.00US in 1000 piece quantities so if a complete PCB, chip, capacitor, and resistors module sells for less than $10 in single piece quantities I'd be suspicious t...
by Paul Hutch
Mon Aug 20, 2018 2:31 pm
Forum: Advanced users
Topic: [Solved] serial port API documentation
Replies: 13
Views: 1597

Re: serial port API documentation

I think you will need to use lower level code to detect a break and depending on the hardware UART's architecture it may not be detectable. Break is simply a signal outside the limits set in the TIA-232 standard (above -3V and below +3V, like a break in the wiring will give). Some modern hardware UA...
by Paul Hutch
Sat Aug 18, 2018 1:31 pm
Forum: Networking and servers
Topic: Remote Desktop to windows performance. Zero W vs 3b+
Replies: 4
Views: 1479

Re: Remote Desktop to windows performance. Zero W vs 3b+

Never tried remote desktop but from a general horsepower perspective the 3B+ is closer in performance to a 10 year old Mac-Mini than it is to a ZeroW.
by Paul Hutch
Sat Aug 18, 2018 12:20 am
Forum: Advanced users
Topic: Floating input on industrial usage
Replies: 9
Views: 913

Re: Floating input on industrial usage

The symptom definitely seems like EMI pickup from the other gear. I'd start by removing the pull down resistor, turning on the internal pull up for the pin, and also add a low value external pull-up to 3.3V for improved noise immunity. I'd start with 1k for the external pull up and go lower if EMI i...
by Paul Hutch
Fri Aug 10, 2018 6:02 pm
Forum: General discussion
Topic: Access com port remotely while using PI as an access point
Replies: 8
Views: 605

Re: Access com port remotely while using PI as an access point

So part of the problem, I think, even with using SSH, is that the RPi no longer has an IP address per se once I have created the bridge from the coding in the link I provided. From the link you provided: If SSH is enabled on the Raspberry Pi access point, it should be possible to connect to it from...

Go to advanced search