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by hampi
Sun Jan 17, 2016 4:04 pm
Forum: Automation, sensing and robotics
Topic: Accuracy of BMP180 sensor.
Replies: 12
Views: 3191

Re: Accuracy of BMP180 sensor.

Maybe I2C problem in reading the registers. I am using this C-program to read the BMP180

https://github.com/oh7bf/I2chipd
by hampi
Sat Jan 16, 2016 7:33 pm
Forum: Automation, sensing and robotics
Topic: Pi, Potentiometer, Stepper Motor
Replies: 5
Views: 1950

Re: Pi, Potentiometer, Stepper Motor

Here is one possibility for simple DC motors

https://github.com/oh7bf/RasPiHBridge/w ... ion-Sensor
by hampi
Sun Dec 27, 2015 6:10 pm
Forum: General discussion
Topic: PIC and RASPEBERRY
Replies: 5
Views: 876

Re: PIC and RASPEBERRY

Or it is possible to use raspberry only and connect all sensors ? Usually it is best to use Raspberry Pi and sensors without an extra micro-controller PIC, AVR or similar. But that depends on the sensors too. For example Raspberry Pi needs a separate A/D-converter chip to read analog voltages. Many...
by hampi
Sat Dec 05, 2015 9:33 am
Forum: General discussion
Topic: Connecting multiple SDA SCL Devices
Replies: 3
Views: 1529

Re: Connecting multiple SDA SCL Devices

Here is an example what I have done for slow I2C

https://github.com/oh7bf/RPiAOneI2cSens ... ensors.pdf
by hampi
Tue Nov 24, 2015 3:59 pm
Forum: General discussion
Topic: sensors
Replies: 1
Views: 376

Re: sensors

You will probably need two or more thermocouples. These are used in mass flow meters to measure gas flow.
by hampi
Sun Nov 22, 2015 1:44 pm
Forum: General discussion
Topic: Using I2C bus sensor
Replies: 2
Views: 413

Re: Using I2C bus sensor

Linux has native support for I2C bus. The Raspberry Pi is different from other computers since you can easily connect new chips to this bus while in other computers you do not have direct hardware access to the I2C.
by hampi
Tue Nov 10, 2015 10:13 pm
Forum: General discussion
Topic: Level Shifer
Replies: 29
Views: 4201

Re: Level Shifer

According to LTSpice circuit does not work between 2.7 V and 3.3 V with BS170. The gate voltage seems to be critical and 3.0 V just at the lower limit. Yes there are other FETs with low Vgs(ON) and few of them are in TO-92 package. Nice video on testing FETs: https://www.youtube.com/watch?v=gloikp9t...
by hampi
Mon Nov 09, 2015 9:41 pm
Forum: General discussion
Topic: Level Shifer
Replies: 29
Views: 4201

Re: Level Shifer

By my experience that circuit works between 3.3 V and 3.0 V (Q3 and Q4 in circuit diagram)

https://github.com/oh7bf/RaspiPwr12V/bl ... pwr12V.pdf

You could just try if it works down to 2.7 V too.
by hampi
Thu Oct 15, 2015 7:30 pm
Forum: Off topic discussion
Topic: IF you are interested in radio....
Replies: 4
Views: 990

Re: IF you are interested in radio....

Nice video from RSGB.

73 de hampi aka oh7bf/f5vgl
by hampi
Wed Sep 30, 2015 7:28 pm
Forum: Beginners
Topic: PCB Board Layout/Design Software
Replies: 11
Views: 3747

Re: PCB Board Layout/Design Software

by hampi
Sat Aug 08, 2015 8:13 am
Forum: Automation, sensing and robotics
Topic: How many Motors can control with one RaspberryPi
Replies: 20
Views: 8058

Re: How many Motors can control with one RaspberryPi

If you want to step all motors simultaneously the best solution would be to control groups of 10 or so steppers with one arduino, and controlling 200/10 = 20 Arduinos by the PI through the serial port (UART) in the PI. Or use ten Raspberry Pis instead of one? Depends how "real time" the motor contr...
by hampi
Fri Jul 31, 2015 5:20 pm
Forum: General discussion
Topic: Powering Multiple Pi's
Replies: 15
Views: 2528

Re: Powering Multiple Pi's

by hampi
Sat Jun 20, 2015 4:42 pm
Forum: Other projects
Topic: Solar Powered Pi
Replies: 3
Views: 1913

Re: Solar Powered Pi

10 W panel and 12 V 7 Ah lead acid battery gave me 55 hours of computer time last week. One week is 168 hours. This system @RPiAOne has been build with cost in mind and should be accessible to most hobby builders. Only very basic and widely available components are used. Presently I am using Raspber...
by hampi
Sat Jun 13, 2015 4:38 pm
Forum: General discussion
Topic: Week-long, portable, power source?!?!?!?
Replies: 8
Views: 2131

Re: Week-long, portable, power source?!?!?!?

Lead acid battery with a small solar panel is quite robust, safe and not too expensive system. For example like this

https://github.com/oh7bf/RaspiPwr12V/wi ... spberry-Pi
by hampi
Sun May 31, 2015 7:41 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C crashes with BCM2835 library functions
Replies: 34
Views: 3656

Re: I2C crashes with BCM2835 library functions

My slow daemon code is here, but I need to still improve it. The structure is likely to change in near future.

https://github.com/oh7bf/Mpl3115a2d
by hampi
Sat May 23, 2015 10:29 am
Forum: Automation, sensing and robotics
Topic: Solar irradiance
Replies: 7
Views: 1597

Re: Solar irradiance

You can do - of course - plots in Python too. Some examples

http://matplotlib.org/

http://www.python-course.eu/tkinter_canvas.php
by hampi
Sun May 17, 2015 7:49 pm
Forum: Automation, sensing and robotics
Topic: Solar irradiance
Replies: 7
Views: 1597

Re: Solar irradiance

Something like this for example: PHP, Java Script, Ajax, Cascading Style Sheets... Very simple plots can be done with PHP GD alone.

For offline plots gnuplot is popular.
by hampi
Wed May 13, 2015 9:49 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Raspberry Pi PIC Programmer using GPIO
Replies: 102
Views: 42381

Re: Raspberry Pi PIC Programmer using GPIO

The GPIO8 in the circuit diagram needs to be configured as floating input without pull up or down at Raspberry Pi. Otherwise the data read contains mostly high states, which gives in a 0xFF... in hexadecimal. I spent some hours to investigate this problem when the device tree was introduced back in ...
by hampi
Mon May 11, 2015 7:30 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Raspberry Pi PIC Programmer using GPIO
Replies: 102
Views: 42381

Re: Raspberry Pi PIC Programmer using GPIO

This piece of assembly code might be useful for testing the programmer on 12f675

https://github.com/oh7bf/PiPIC/tree/master/asm

It might be a good idea to put the rpp-tlc under version control too. For example by using the github or something similar.
by hampi
Sat May 09, 2015 7:41 am
Forum: Beginners
Topic: possibility to charge while using?
Replies: 7
Views: 875

Re: possibility to charge while using?

I would go with a two batt system for efficient charging and for isolation. The OP did not specify what kind of battery is needed. With a sealed lead acid battery and small solar panel you can do with one battery only. This is how my @RPiAOne project works. Also in cars there is typically only one ...
by hampi
Sat Apr 04, 2015 8:00 pm
Forum: General discussion
Topic: Is My Pi Safe?
Replies: 48
Views: 5274

Re: Is My Pi Safe?

morphy_richards wrote:People in this thread keep mentioning something about key only ssh and abandoning passwords altogether.
Or using one-time passwords? Not really expert on this field.
by hampi
Fri Mar 27, 2015 12:39 pm
Forum: General discussion
Topic: Intended for kids and hijacked by adult hobbyists?
Replies: 19
Views: 2517

Re: Intended for kids and hijacked by adult hobbyists?

There is no age for learning something new. I think this forum profits from mixture of old and new ideas and from different points of view.
by hampi
Thu Mar 19, 2015 9:22 pm
Forum: Automation, sensing and robotics
Topic: When you need more power - how to be safe?
Replies: 17
Views: 3076

Re: When you need more power - how to be safe?

For indoor use a recycled PC case should work as a safe and economic enclosure for the power supply module, Raspberry Pi and other things - just an idea.
by hampi
Tue Mar 17, 2015 9:42 pm
Forum: Automation, sensing and robotics
Topic: When you need more power - how to be safe?
Replies: 17
Views: 3076

Re: When you need more power - how to be safe?

RaTTuS wrote:can anybody recommend a 12V distribution panel [fused with blade fuses idealy] so I can use one of this but split it into 12+ output channels...
Something like this?

http://www.g0hwc.com/anderson-powerpole.html
by hampi
Tue Mar 17, 2015 9:36 pm
Forum: Advanced users
Topic: how turn-on a rpi with a clock module?
Replies: 6
Views: 1262

Re: how turn-on a rpi with a clock module?

I have a pretty good solution for that

https://github.com/oh7bf/RaspiPwr12V

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