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by rzusman
Fri Jan 15, 2016 8:28 pm
Forum: Automation, sensing and robotics
Topic: Timer controller interface using coaxial cable? Possible?
Replies: 10
Views: 1104

Re: Timer controller interface using coaxial cable? Possible

You need to determine what type of signal (voltage levels and protocol) was being sent down the coax.
by rzusman
Fri Jan 15, 2016 2:43 pm
Forum: Beginners
Topic: Temperature Control
Replies: 6
Views: 831

Re: Temperature Control

I've run these for over 50' in "parasite power" mode.
by rzusman
Fri Jan 15, 2016 3:44 am
Forum: Troubleshooting
Topic: High pitch buzzing noise from Pi
Replies: 7
Views: 1344

Re: High pitch buzzing noise from Pi

It's probably just the power supply magnetics vibrating.
Ignore it.
by rzusman
Thu Jan 14, 2016 1:57 am
Forum: Media centres
Topic: sending IR (knowing the ir signal)
Replies: 8
Views: 1431

Re: sending IR (knowing the ir signal)

Research lirc.
It can send arbitrary commands.
by rzusman
Wed Jan 13, 2016 9:25 pm
Forum: Compute Module
Topic: Boot up time in compute module
Replies: 4
Views: 1213

Re: Boot up time in compute module

Oh, I've figured out how to do it!

I'm using 50F of capacitance to give me 100W•S of power to allow the Pi to shutdown gracefully during a power fail. I just mentioned it to bring it to the OP's attention.
by rzusman
Wed Jan 13, 2016 6:14 pm
Forum: Compute Module
Topic: Boot up time in compute module
Replies: 4
Views: 1213

Re: Boot up time in compute module

I am designing an embedded controller with the Compute Module. With a small OS (I'm playing with Minibian right now), boot times are under 10 seconds. The big issue is not boot time, though - it's shutdown time! You need to solve the shutdown-and-save-state issue if you plan on flipping the power of...
by rzusman
Wed Jan 13, 2016 3:03 pm
Forum: Advanced users
Topic: ULN2803 Problem: LED and Motor (series)
Replies: 13
Views: 2052

Re: ULN2803 Problem: LED and Motor (series)

No, you don't want the LED in series with your motor! That just shows you don't understand what you are doing. Put the LED in parallel with the motor and remember to use a dropping resistor. Ask yourself - how much current does it take to run the motor? Then, ask yourself - how much current can an L...
by rzusman
Wed Jan 13, 2016 1:03 am
Forum: Advanced users
Topic: ULN2803 Problem: LED and Motor (series)
Replies: 13
Views: 2052

Re: ULN2803 Problem: LED and Motor (series)

You don't want the LED in series with your motor!
by rzusman
Mon Jan 11, 2016 1:47 am
Forum: General discussion
Topic: Looking for a Wifi Dongle That Won't Crash???
Replies: 8
Views: 1248

Re: A Wifi Dongle That Won't Sleep???

I've never heard of one that has a sleep mode.
What problem are you trying to solve?
by rzusman
Sun Jan 10, 2016 9:45 pm
Forum: General discussion
Topic: micro SD with 512GB for $10 (Fake)
Replies: 16
Views: 3755

Re: micro SD with 512GB for $10

The way most people “test” these is to plug them into their computer. If they mount, and say that there is 512GB of capacity, they believe it. As you have noted, writing small files will succeed - it’s only when you finally write something big and important to the device that you find out that it’s ...
by rzusman
Sun Jan 10, 2016 9:43 pm
Forum: Beginners
Topic: Temperature Control
Replies: 6
Views: 831

Re: Temperature Control

Do you have a temperature measurement device connected to the Pi?
If so, read it when you want to know the temperature, or read it periodically to get an idea of the temperature trend.
If you don’t have one, that’s the next step...
by rzusman
Sun Jan 10, 2016 9:39 pm
Forum: Camera board
Topic: Time lapse project
Replies: 7
Views: 927

Re: Time lapse project

Try it as root, or preface with ‘sudo'
by rzusman
Sun Jan 10, 2016 6:49 pm
Forum: General discussion
Topic: micro SD with 512GB for $10 (Fake)
Replies: 16
Views: 3755

Re: micro SD with 512GB for $10

I'm curious, is it useful despite the likely problems ?
No.

Buy a reputable one.
by rzusman
Sun Jan 10, 2016 6:35 pm
Forum: General discussion
Topic: micro SD with 512GB for $10 (Fake)
Replies: 16
Views: 3755

Re: micro SD with 512GB for $10

I’ll bet really money that it’s a fake.
by rzusman
Sat Jan 09, 2016 9:44 pm
Forum: Automation, sensing and robotics
Topic: Where to get quality sensors
Replies: 7
Views: 1249

Re: Where to get quality sensors

What accuracy do you need? The DS18B20 is guaranteed to be within ± .5C, so that takes care of your temperature. Humidity is another issue - those sensors are notoriously inaccurate, and I doubt you will be able to get better than a few % accuracy without calibration. http://www.sensorsmag.com/senso...
by rzusman
Sat Jan 09, 2016 8:04 pm
Forum: HATs and other add-ons
Topic: Show 5V on ground pin
Replies: 10
Views: 2181

Re: Show 5V on ground pin

Throw that tester away.
It’s useless for this.
by rzusman
Sat Jan 09, 2016 5:13 pm
Forum: Windows 10 for IoT
Topic: IR Communication with RP2
Replies: 10
Views: 1599

Re: IR Communication with RP2

Look into IRDA.
It used to be well-supported in Windows, don't know about now.
by rzusman
Sat Jan 09, 2016 12:14 am
Forum: General discussion
Topic: Minibian
Replies: 6
Views: 1058

Re: Minibian

I can't find a Minibian forum. I have now built abt 12 Raspberry environments, some just for fun, some for semi-prof laboratory systems and some security systems. Next 4 are on the table. Minibian has been the best so far, when you are building something serious. I think I have collected some knowl...
by rzusman
Fri Jan 08, 2016 1:54 am
Forum: Beginners
Topic: MOSFET ramp (12V) to light LED in series (will it blow up?)
Replies: 12
Views: 1928

Re: MOSFET ramp (12V) to light LED in series (will it blow u

Why does the title of this thread say “ramp?”
This is a MOSFET switch. You can control the brightness with PWM, but not a linear ramp.
by rzusman
Wed Jan 06, 2016 11:42 pm
Forum: Automation, sensing and robotics
Topic: Measure current and voltage from sunpanel
Replies: 12
Views: 2066

Re: Measure current and voltage from sunpanel

This board uses a .1Ω current sense resistor, and can only handle 3.2A.

What ratings are your solar panels? A 100W panel is going to exceed the current limit for this device.
by rzusman
Fri Jan 01, 2016 11:36 pm
Forum: Compute Module
Topic: Compute Module USB Over-current detection
Replies: 0
Views: 435

Compute Module USB Over-current detection

I noticed that I received an over-current warning when I plugged too many USB devices into the Compute Module development board, but I can't see where the detection is occurring by looking at the schematic. As far as I can see, the VBUSA which powers the Host USB port is connected directly to 5V (wi...

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