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by rgrbic
Thu Feb 19, 2015 9:28 am
Forum: General discussion
Topic: Connecting DEC VT terminal to Raspberry Pi
Replies: 0
Views: 385

Connecting DEC VT terminal to Raspberry Pi

If someone is interested in connecting an old DEC terminal to Raspberry Pi, here you can find some information.
by rgrbic
Mon Jan 19, 2015 8:59 am
Forum: Automation, sensing and robotics
Topic: Motor Control issues
Replies: 6
Views: 1005

Re: Motor Control issues

As mahjongg said, you don't have feedback regarding motor position. you can use mechanical swithc or reed switch for sensing open/closed door position.
by rgrbic
Mon Jan 12, 2015 5:12 pm
Forum: Automation, sensing and robotics
Topic: ADXL345 only returning -2.048
Replies: 29
Views: 3876

Re: ADXL345 only returning -2.048

Does the adxl345 board have pull up resistors? If so maybe you have too strong pull up on the bus since you have parallel connection of resistors on the adxl board and on raspberry pi sda and scl lines.
by rgrbic
Mon Jan 12, 2015 11:01 am
Forum: Automation, sensing and robotics
Topic: ADXL345 only returning -2.048
Replies: 29
Views: 3876

Re: ADXL345 only returning -2.048

Just to be sure, there is pull up resistor on i2c line?
by rgrbic
Mon Jan 12, 2015 10:40 am
Forum: Automation, sensing and robotics
Topic: battery
Replies: 4
Views: 687

Re: battery

Different batteries have different charachteristics (voltage, capacity, internal resistance, discharge current and so on).
buy appropriate battery
by rgrbic
Sat Jan 10, 2015 2:42 pm
Forum: Automation, sensing and robotics
Topic: ADXL345 only returning -2.048
Replies: 29
Views: 3876

Re: ADXL345 only returning -2.048

Maybe is accelerometer in standby mode. Check the datasheet.
by rgrbic
Sat Jan 10, 2015 9:31 am
Forum: Automation, sensing and robotics
Topic: ADXL345 only returning -2.048
Replies: 29
Views: 3876

Re: ADXL345 only returning -2.048

I didn't check the examples. These accelerometers have +-2g by default which you get as 2048 or -2048 so you are getting constantly maximal value. Maybe the programs are written for different resolutions?
by rgrbic
Fri Jan 09, 2015 6:15 pm
Forum: Automation, sensing and robotics
Topic: Pushing temperature to a url
Replies: 6
Views: 1352

Re: Pushing temperature to a url

You can use websockets to send the data to webpage (client). Here is one example how to use websockets to display temperature on a webpage.
by rgrbic
Fri Jan 09, 2015 5:41 pm
Forum: Automation, sensing and robotics
Topic: question on motors
Replies: 7
Views: 1158

Re: question on motors

don't do that
it is probably asynchronous single-phase motor
by rgrbic
Fri Jan 09, 2015 5:35 pm
Forum: Automation, sensing and robotics
Topic: Wireless sensors.. Serial over BT/WIFI or other RF?
Replies: 5
Views: 2203

Re: Wireless sensors.. Serial over BT/WIFI or other RF?

I used nrf24l01 modules. Here is text about it.
by rgrbic
Wed Nov 19, 2014 12:06 pm
Forum: General discussion
Topic: Can not connect with Tornado on the Pi. Need help!!!
Replies: 7
Views: 1235

Re: Can not connect with Tornado on the Pi. Need help!!!

Connect RPi - router with eternet cable and see if this is still happening. If not, the problem is in your wifi adapter.
by rgrbic
Wed Nov 19, 2014 11:35 am
Forum: Networking and servers
Topic: distributed network of sensors
Replies: 7
Views: 1721

Re: distributed network of sensors

Thanks guys. Does anyone have any experience with waterproof housings for Raspberry Pi setups? I will have to run the cables from the solar panels into the enclosure, and will have to run the sensors out of the enclosure. Are there any enclosures that might be designed for this kind of setup, or wo...
by rgrbic
Tue Nov 18, 2014 3:09 pm
Forum: Networking and servers
Topic: distributed network of sensors
Replies: 7
Views: 1721

Re: distributed network of sensors

You can go with microcontrollers paired with zigbee modules for communication.
by rgrbic
Mon Sep 29, 2014 10:04 am
Forum: Beginners
Topic: How to sum up the data read by sensor?
Replies: 5
Views: 816

Re: How to sum up the data read by sensor?

You have to get the value from sensor in liters per second. Read the sensor every second and just add the reading to some variable which you have to set to 0 every day.
Or, if you don't need current flow then just count the pulses and at the end of a day calculate consumption in liters.
by rgrbic
Sun Sep 28, 2014 7:10 am
Forum: Beginners
Topic: Safe shutdown button
Replies: 10
Views: 2508

Re: Safe shutdown button

Here you can find information how to make shutdown/reset button for RPi. Short button press resets RPi, longer (more than 3 sec) press shutdowns RPi.
by rgrbic
Thu Aug 14, 2014 6:24 am
Forum: Beginners
Topic: Total Noob- Temperature sensing project
Replies: 3
Views: 664

Re: Total Noob- Temperature sensing project

Here you can see how to connect DS18B20 sensors to the Raspberry Pi, read the values and store them to mysql database.
by rgrbic
Thu Aug 14, 2014 6:20 am
Forum: General discussion
Topic: Using Raspberry pi with high current motor
Replies: 6
Views: 1010

Re: Using Raspberry pi with high current motor

Not enough information about the drive and there is no picture below. But generally speaking yes, you should connect Pi ground with driver electronics ground.
by rgrbic
Tue Aug 12, 2014 5:40 pm
Forum: Automation, sensing and robotics
Topic: RPi for prototyping, then micro-controller for "deployment"?
Replies: 3
Views: 709

Re: RPi for prototyping, then micro-controller for "deployme

I would use some microcontroller development board instead of prototyping on RPi since they are quite different.
by rgrbic
Tue Aug 12, 2014 6:40 am
Forum: Networking and servers
Topic: Ways to push data realtime from R-pi to remote web server?
Replies: 3
Views: 2410

Re: Ways to push data realtime from R-pi to remote web serve

You can use websockets. See some examples here.
by rgrbic
Thu Aug 07, 2014 11:21 pm
Forum: Automation, sensing and robotics
Topic: Oil Tank Monitor Project
Replies: 9
Views: 5773

Re: Oil Tank Monitor Project

On to the next question. Volumetric change of oil. I can't remember the formula off hand, but there is a formula where you can plug in the temperature of the fluid, some thermal property of the fluid(i think), and you will be able to work out a volume. Then you get a standard volume for oil for a t...
by rgrbic
Thu Aug 07, 2014 4:38 pm
Forum: Beginners
Topic: Transistors and the Raspi.
Replies: 4
Views: 731

Re: Transistors and the Raspi.

The approach is ok. See here.
by rgrbic
Thu Aug 07, 2014 8:36 am
Forum: General discussion
Topic: Safety And The Pi
Replies: 9
Views: 1257

Re: Safety And The Pi

If you use appropriate power supply, I don't see how RPi can explode. RPi has fuse which is fully opened around 1A. if you put in in a container holding petrol fumes to about 5% and drop metal paper clips on it while powered up you may get an explosion ;) Or if you put bomb on it and connect the bo...
by rgrbic
Thu Aug 07, 2014 8:27 am
Forum: General discussion
Topic: Safety And The Pi
Replies: 9
Views: 1257

Re: Safety And The Pi

If you use appropriate power supply, I don't see how RPi can explode. RPi has fuse which is fully opened around 1A.
by rgrbic
Wed Aug 06, 2014 5:53 pm
Forum: Python
Topic: Make Logic High (>3V)
Replies: 5
Views: 1003

Re: Make Logic High (>3V)

You should provide more details about laser and driving circuit.

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