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by wh7qq
Sun May 27, 2018 5:49 am
Forum: Off topic discussion
Topic: need help to customize a component to power the pi
Replies: 4
Views: 118

Re: need help to customize a component to power the pi

Although it is not pretty or convenient, probably the best bet is to have separate supplies for the 3B+ and the display. The B+ with its onboard wifi, will draw more power than the 3B and that probably taxes the ability of the mp1484 and the 2A supply. Bigger caps won't help and unless you have the ...
by wh7qq
Sat May 26, 2018 5:26 am
Forum: Beginners
Topic: Raspberry UI
Replies: 3
Views: 147

Re: Raspberry UI

If you already have a HDMI monitor like a newer TV or computer monitor, you need only keyboard, mouse, power supply and a micro SD card, 8G or larger. With those things, it will act as a stand alone computer, albeit a slow one, depending on model. You don't say what you want to do with the tank so t...
by wh7qq
Fri May 25, 2018 10:40 pm
Forum: Troubleshooting
Topic: Motor Controllers With Raspberry instead of Arduino - lack of software support
Replies: 5
Views: 146

Re: Motor Controllers With Raspberry instead of Arduino - lack of software support

I have been through some of the same issues in dealing with stepper motors with the RPi but several points have to be considered. First, the availability of software for the RPi. as with all Linux, is based on the interest of persons with sufficient skill and time to develop it. These are usually vo...
by wh7qq
Thu May 24, 2018 2:37 am
Forum: Troubleshooting
Topic: Raspberry Pi 3b+ has bad wifi download speed
Replies: 5
Views: 136

Re: Raspberry Pi 3b+ has bad wifi download speed

The only thing I can see is that your "power management" is turned off. I have no idea of whether or not that is the cause. What confuses me most of all is the reversal of download and upload speeds. Mine is a 3B (no +) but I am unaware of why the 3B+ should be any different. How are other non-RPi c...
by wh7qq
Wed May 23, 2018 8:31 pm
Forum: Troubleshooting
Topic: Raspberry Pi 3b+ has bad wifi download speed
Replies: 5
Views: 136

Re: Raspberry Pi 3b+ has bad wifi download speed

Running a 3B with wireless mouse and wired keyboard: speedtest-cli Retrieving speedtest.net configuration... Testing from ViaSat (99.197.43.141)... Retrieving speedtest.net server list... Selecting best server based on ping... Hosted by TEC (Jackson, MS) [0.01 km]: 396.272 ms Testing download speed....
by wh7qq
Wed May 23, 2018 7:56 pm
Forum: Troubleshooting
Topic: Signal Out Of Range
Replies: 1
Views: 53

Re: Signal Out Of Range

You don't provide much information about "it doesn't work" but on a hunch, check out this troubleshooting forum link: https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=5851. If you need more help here, we will need to know things like model RPi, version of Raspbian, make and model of video mon...
by wh7qq
Wed May 23, 2018 7:46 pm
Forum: General discussion
Topic: Special-case power requirements
Replies: 11
Views: 340

Re: Special-case power requirements

As the time frame that the "rf kill switch" occurs in the boot sequence is much longer than even multiple passes down the 20' transmission line, I think it a much more likely scenario for the actual failure. The big cap stabilizes the voltage supplied to the load at the end. Discovering the "right" ...
by wh7qq
Wed May 23, 2018 6:18 am
Forum: General discussion
Topic: Special-case power requirements
Replies: 11
Views: 340

Re: Special-case power requirements

Is the heat sink on the 7805 getting hot? Check it from start to crash and see. If your system were drawing 400 ma, that would be 2.8 watts (7 volts X .400 A) and 3-5 min. might be the time required to cause the 7805 to overheat if the heat sink is not up to it. If the heat sink was not applied with...
by wh7qq
Tue May 22, 2018 10:37 pm
Forum: General discussion
Topic: Special-case power requirements
Replies: 11
Views: 340

Re: Special-case power requirements

The 20' of stranded 2 conductor wire, if copper, actually translates to a conductor length of 40' and has something around 0.4 ohms resistance (according to copper wire tables). At 1 amp, that is a .4V drop. You did not mention what kind of IR lighting you are using. It would seem that the 7805 is c...
by wh7qq
Sun May 20, 2018 7:11 pm
Forum: Troubleshooting
Topic: I cannot get my Pi to connect to the internet
Replies: 9
Views: 240

Re: I cannot get my Pi to connect to the internet

B. Goode's comment is right on target and should fix the problem. You can find the IP address assigned to the RPi on your router's web interface (administration) pages. There is usually a "devices" listing of the connected devices. If you have not gone to those pages, they can be found by simply put...
by wh7qq
Sat May 19, 2018 11:45 pm
Forum: General discussion
Topic: Problem on MAX30105 sensor on Raspberry Pi 3
Replies: 14
Views: 406

Re: Problem on MAX30105 sensor on Raspberry Pi 3

Nicole Chow wrote From your opinion, the only way to solve is to connect the sensor on Arduino and communicate with raspberry pi ? Because the data collected will be needed to convert into CSV file for analyzing and compared. I had tried the sensor on Arduino and the green LED also on at 3.3V, does ...
by wh7qq
Sat May 19, 2018 6:15 pm
Forum: General discussion
Topic: about how many sensors we can connect to raspberry pi 3
Replies: 2
Views: 99

Re: about how many sensors we can connect to raspberry pi 3

The simple approach to soil moisture is to connect the signal output to an analog comparator IC and use that output (hi or lo) to trigger a GPIO pin. Theoretically, you could use as many sensors as you have GPIO inputs on the RPi. You use a simple pot to adjust the moisture trip point. Long term sta...
by wh7qq
Sat May 19, 2018 5:47 pm
Forum: Automation, sensing and robotics
Topic: Alexa (installed on the same rpi) to control relay on RPI 3B
Replies: 1
Views: 121

Re: Alexa (installed on the same rpi) to control relay on RPI 3B

I don't know from Alexa but all you have to do is make it control a GPIO pin. If Alexa can issue commands to the RPi, it is trivial. Use GPIO commands. If not, maybe another can help.
by wh7qq
Sat May 19, 2018 5:37 pm
Forum: Other projects
Topic: Pi to open garage door
Replies: 1
Views: 106

Re: Pi to open garage door

As we have no idea of the input configuration of the RC receiver, it would be difficult to answer your question of hooking it up to an RPi. On the other hand, most of the garage door openers are activated with simple contact closures (such as the button by the entry to the garage) so a Zero W with a...
by wh7qq
Sat May 19, 2018 5:21 pm
Forum: Advanced users
Topic: Pi 3 B+ fries if 3V3 rail is shorted to 5V
Replies: 19
Views: 561

Re: Pi 3 B+ fries if 3V3 rail is shorted to 5V

The real protection of a more costly computer is that the OP probably would not have bought one if it cost more. Just wanting a cheap computer to play with and then crying when it gets broken by rough use.... Actually the RPis have been very robust. I expected death many times after my clumsy handli...
by wh7qq
Sat May 19, 2018 3:56 am
Forum: Troubleshooting
Topic: Raspberry pi 3 won't download php5
Replies: 2
Views: 64

Re: Raspberry pi 3 won't download php5

If it isn't in the repo, it won't load with apt. To get it, you will probably have to get the code off Github and compile it yourself.
by wh7qq
Sat May 19, 2018 3:51 am
Forum: Advanced users
Topic: Pi 3 B+ fries if 3V3 rail is shorted to 5V
Replies: 19
Views: 561

Re: Pi 3 B+ fries if 3V3 rail is shorted to 5V

There was another instance of this reported recently. If shorting 5V to 3.3V doesn't fry the cpu and other things, it is sheer, blind luck and not a bug. Don't blame the 3B+ or cry bug when doing something really dumb fries it. If your 3B didn't fry with the same screw-up, it is just luck. 3.3v is t...
by wh7qq
Fri May 18, 2018 9:33 pm
Forum: General discussion
Topic: Problem on MAX30105 sensor on Raspberry Pi 3
Replies: 14
Views: 406

Re: Problem on MAX30105 sensor on Raspberry Pi 3

You piqued my curiosity on the MAX30105...I haven't used it yet but it reminded me of a product my R&D group had made custom by a Texas fabricator years ago. From what I see, the information on Sparkfun's side is all based on the Arduino so the code they refer to is also arduino based and in their m...
by wh7qq
Wed May 16, 2018 7:47 pm
Forum: Networking and servers
Topic: Found out why the signal is weak (Zero W) FYI
Replies: 1
Views: 185

Re: Found out why the signal is weak (Zero W) FYI

Looks like somebody did a clumsy removal or it somehow was broken off. The gold plating on the contact surfaces have been pulled up. The component is present on my example and while range is not great, it is better than 20'. I have always attributed it to the tiny antennas...size does count where an...
by wh7qq
Mon May 14, 2018 4:21 pm
Forum: Troubleshooting
Topic: Pin 1 and Pin 2 short circuited
Replies: 9
Views: 306

Re: Pin 1 and Pin 2 short circuited

It is always possible that you lucked out and did not fry the RPi so try it with a freshly burned uSD card. If it does not start, it is probably best just to bite the bullet and get a new RPi. Waiting a day or two to allow the poly fuse to repair itself might work...or not.
by wh7qq
Sun May 13, 2018 8:08 pm
Forum: Beginners
Topic: 2 x ds18b20 and expansion board
Replies: 3
Views: 65

Re: 2 x ds18b20 and expansion board

1-wire....correct. Not i2c.
by wh7qq
Sun May 13, 2018 7:53 pm
Forum: Beginners
Topic: 2 x ds18b20 and expansion board
Replies: 3
Views: 65

Re: 2 x ds18b20 and expansion board

The RPi will be perfectly happy with the multiple ds18b20s and all that is needed is to tie the sensors together in parallel with a single set of wires going to the RPi, including the single pull-up resistor (between 4.7 and 10K) from 3.3V to the i2c input. Each ds18b20 has an individual code number...
by wh7qq
Sun May 13, 2018 7:02 pm
Forum: General discussion
Topic: Relay <-> Sprinkler Valve
Replies: 5
Views: 149

Re: Relay <-> Sprinkler Valve

I have not used the 406 with an RPi. It is specified to work with the Arduino which outputs a wider swing (5V) vs the RPi (3.3v) so it may not switch reliably with the lower voltage and may require additional interfacing (a transistor to the 5V supply). See http://elinux.org/RPi_GPIO_Interface_Circu...
by wh7qq
Sat May 12, 2018 8:53 pm
Forum: Troubleshooting
Topic: Raspberry Pi doesn't boot. Doesn't see any SD
Replies: 1
Views: 58

Re: Raspberry Pi doesn't boot. Doesn't see any SD

You may have "pulled the plug" without doing a proper shutdown sequence. That can mess up the boot partition. Reflash the uSD card with Raspbian-latest and try again. Next time, use the "Shutdown" command from the main menu on the desktop or from a command line, type

Code: Select all

 sudo shutdown -h now
.
by wh7qq
Sat May 12, 2018 4:39 am
Forum: Troubleshooting
Topic: Raspberry Pi 3 suddenly quits working and won't turn back on
Replies: 1
Views: 81

Re: Raspberry Pi 3 suddenly quits working and won't turn back on

Basic troublehooting procedure: 1. disconnect the displays and keep only the mouse, keyboard and uSD card and plug into an HDMI display like a TV or HMDI monitor. If you have a switch in the 5VDC line from the power supply, use a plain vanilla power cord (but not a phone charger cord). 2. Try it aga...

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