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by bbodin
Fri Oct 24, 2014 11:49 am
Forum: Graphics programming
Topic: YUV422 to RGB conversion
Replies: 13
Views: 7054

Re: YUV422 to RGB conversion

If the color space conversion is just for display, it can be avoided by modifying the dispmanx.c demo program to directly take YUV422 images for display. There are several YUV422 formats: VC_IMAGE_YUV422, VC_IMAGE_YUV422PLANAR, VC_IMAGE_YUV422_YUYV, VC_IMAGE_YUV422_YVYU, VC_IMAGE_UYVY and VC_IMAGE_Y...
by bbodin
Sun Oct 19, 2014 12:55 pm
Forum: OpenMAX
Topic: OpenMAX IL Python Package
Replies: 10
Views: 5175

Re: OpenMAX IL Python Package

The latest omxilc.py and omxjpgdec.py have been uploaded.
by bbodin
Fri Oct 17, 2014 7:05 pm
Forum: OpenMAX
Topic: OpenMAX IL Python Package
Replies: 10
Views: 5175

Re: OpenMAX IL Python Package

Do you know if the availability of libopenmaxil.so is covered by mesa_utils?
I have no idea.
by bbodin
Fri Oct 17, 2014 1:28 pm
Forum: OpenMAX
Topic: OpenMAX IL Python Package
Replies: 10
Views: 5175

Re: OpenMAX IL Python Package

One way to use a c array directly is to cast it to a ctypes pointer to python object. For example, if c_array is an array of c_array_len integers, first define: C_INTARRAY = ctypes.c_int * c_array_len CP_INTARRAY = ctypes.POINTER(C_INTARRAY) Then cast c_array to cp_array as: cp_array = ctypes.cast(c...
by bbodin
Fri Oct 17, 2014 1:02 am
Forum: OpenMAX
Topic: OpenMAX IL Python Package
Replies: 10
Views: 5175

Re: OpenMAX IL Python Package

I found and fixed the issues with the JPEG decoder. I also made some improvements to the code. I ran the decoder for 1 million iterations over a single 1920x1080 jpg file. It took 13h 51m 4s to complete, resulting in 20 frames/s. I also the code with a sequence of various jpg sizes with a few progre...
by bbodin
Wed Oct 15, 2014 3:16 am
Forum: OpenMAX
Topic: OpenMAX IL Python Package
Replies: 10
Views: 5175

OpenMAX IL Python Package

I have written a python package which defines a component class for writing IL client applications in Python 2.7.3 for the RPi. It is based on the file ilclient.c developed by Broadcom which defines an IL client side library. It is also based on the python module pyopenmax.py developed by Peter de R...
by bbodin
Wed Aug 13, 2014 3:38 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Can the UART go faster than 115200?
Replies: 12
Views: 9249

Re: Can the UART go faster than 115200?

Above 115200 kbps, these values are supported by stty: 230400, 460800, 500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000, 2500000, 3000000, 3500000 and 4000000.

Reference: coreutils.info section 19.2.7 Special settings. Use "info stty" to read the built-in info file.
by bbodin
Wed Aug 13, 2014 2:33 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Can the UART go faster than 115200?
Replies: 12
Views: 9249

Re: Can the UART go faster than 115200?

It appears that stty doesn't support non-standard baud rates. If you want to go higher than 115200 kbps, try a standard value such as 230400, 460800 or 921600.
by bbodin
Sat Aug 09, 2014 2:14 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Using the MCP4131 digital pot safely
Replies: 4
Views: 2262

Re: Using the MCP4131 digital pot safely

Supplementary. Given I have a standard 3 wire SPI on the other channel does it matter if I have the resistor at the MIMO pin rather than the Pi end? Is this OK? Pi MOSI --------+---------------- DIN ADC | | +----RESISTOR---- MIMO POT Rather than? Pi MOSI ----RESISTOR----+-------- DIN ADC | | +-----...
by bbodin
Sat Aug 09, 2014 12:28 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Using the MCP4131 digital pot safely
Replies: 4
Views: 2262

Re: Using the MCP4131 digital pot safely

Since the SDI/SDO pin of the MCP4131 has an open-drain drive, it is protected from a drive conflict. To protect the Pi's MOSI gpio pin, ensure that it is configured as an open-drain output. If that is not possible, add a series resistor (about 200 ohm) between the Pi's MOSI and MCP4131's SDI/SDO to ...
by bbodin
Mon Aug 04, 2014 12:49 pm
Forum: General discussion
Topic: changing nano colour scheme??
Replies: 20
Views: 5423

Re: changing nano colour scheme??

Vi is like an eletests club for masochists. As a long-time user of VI, I'm in disbelief that this statement came from a forum moderator. Why? Is a moderator not allowed to air an opinion? Everybody is certainly entitled to his/her own opinion. However, is this forum a place to air an off-topic opin...
by bbodin
Mon Aug 04, 2014 11:59 am
Forum: General discussion
Topic: changing nano colour scheme??
Replies: 20
Views: 5423

Re: changing nano colour scheme??

Jessie wrote:Vi is like an eletests club for masochists.
As a long-time user of VI, I'm in disbelief that this statement came from a forum moderator.
by bbodin
Sun Aug 03, 2014 10:59 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: maximum cable length I2C with twisted pair?
Replies: 62
Views: 30550

Re: maximum cable length I2C with twisted pair?

I spent a lot of time more than 14 years ago exploring the 1 wire bus (microLAN) and devices and developed them into products for industrial applications. There used to be more hard-copy documentation from Dallas Semiconductor (before it was acquired by Maxim Integrated) then what can found on Maxim...
by bbodin
Sat Aug 02, 2014 9:52 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: maximum cable length I2C with twisted pair?
Replies: 62
Views: 30550

Re: maximum cable length I2C with twisted pair?

Regarding 1-W BUS, I couldn't find any expanders. The BUS was working fine with a bi-directional level-shifter (from 3.3v to 5V and vice-versa) untill I connected a "satelite" that was really far away (I guess its over the 20m from the PI). Googled around and found that adding a 340 Ohm pull-up res...
by bbodin
Sat Aug 02, 2014 4:33 pm
Forum: User groups and events
Topic: Raspberry Pi Users in Shanghai, China
Replies: 9
Views: 2605

Re: Raspberry Pi Users in Shanghai, China

Does the red B+ (improved model B) even exist?

There are a lot red B on Aliexpress but I couldn't find any red B+.
by bbodin
Sat Aug 02, 2014 12:25 pm
Forum: General discussion
Topic: LED help please
Replies: 91
Views: 7030

Re: LED help please

3 Parallel of 3 Series Connected 1W LEDs
3x3_1W_LEDs.JPG
3x3_1W_LEDs.JPG (27.1 KiB) Viewed 1260 times
Note the cathode (negative) marking on one side of the LED.
by bbodin
Sat Aug 02, 2014 11:38 am
Forum: General discussion
Topic: Fonts on this board
Replies: 4
Views: 644

Re: Fonts on this board

[font=courier new]This line should be displayed in Courier New font[/font]
but it is not supported.
by bbodin
Fri Aug 01, 2014 9:28 pm
Forum: General discussion
Topic: LED help please
Replies: 91
Views: 7030

Re: LED help please

You connect nine of those 1W LEDs in a 3x3 configuration (3 parallel strings, each string having 3 series connected LEDs) and use the same current regulator for the 10W LED.

(By competition, I meant Philips - not you).
by bbodin
Fri Aug 01, 2014 8:10 pm
Forum: General discussion
Topic: LED help please
Replies: 91
Views: 7030

Re: LED help please

Not a whole lot of details. Competition? Another thing to consider is instead of a higher wattage LED which increases the lux but makes it fall off quickly outside the illumination area, use several smaller wattage LEDs which distribute the lux more evenly. This approach would make heat management s...
by bbodin
Fri Aug 01, 2014 6:16 pm
Forum: General discussion
Topic: LED help please
Replies: 91
Views: 7030

Re: LED help please

What you are trying to do is fascinating. Thank you for giving me an interest in this area of research. Most of the lettuce sold at our local groceries is hydroponic. Besides being clean, an efficient use of water and nutrients, that method of growing vegetables takes the weather and season dependen...
by bbodin
Fri Aug 01, 2014 1:35 pm
Forum: General discussion
Topic: LED help please
Replies: 91
Views: 7030

Re: LED help please

by bbodin
Fri Aug 01, 2014 10:38 am
Forum: General discussion
Topic: LED help please
Replies: 91
Views: 7030

Re: LED help please

The relay is just a switch to close or interrupt an electrical circuit. You can skip it in your initial built.
by bbodin
Thu Jul 31, 2014 7:03 pm
Forum: General discussion
Topic: LED help please
Replies: 91
Views: 7030

Re: LED help please

Here's the connection diagram for the components you bought to make a 10W LED circuit controllable by a RPi. A_10W_LED_Circuit.JPG There are only two wires going from the relay board to the RPi: CH-1 and GND. To test the circuit without an RPi, you can connect a 3V battery across these two wires to ...
by bbodin
Thu Jul 31, 2014 3:16 pm
Forum: General discussion
Topic: Model B availability
Replies: 18
Views: 1721

Re: Model B availability

I just checked the availability of the B model at MCM Electronics. It's on back order with an estimated ship date of August 22. Microcenter has some stock with a discount price of $29.99. If you are in the US and need the B, you can grab it at Microcenter or wait for 3 weeks until MCM restocks. A le...
by bbodin
Thu Jul 31, 2014 2:31 pm
Forum: General discussion
Topic: LED help please
Replies: 91
Views: 7030

Re: LED help please

The following relays can be controlled by a 3.3V signal and are therefore compatible with the RPi: 2-Channel SPDT 12V 360mW Coil 10A Contact 4-Channel SPDT 12V 360mW Coil 10A Contact 8-Channel SPDT 12V 360mW Coil 10A Contact You may want to go with the 8-channel relay which gives you the abililty to...

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