Go to advanced search

by kaos
Thu May 16, 2013 8:14 pm
Forum: Camera board
Topic: Anyone who ordered from RS get their camera yet?
Replies: 49
Views: 6254

Re: Anyone who ordered from RS get their camera yet?

Ordered mine on Tuesday, and got a dispatch notification today.

--
Kári.
by kaos
Tue May 14, 2013 1:12 pm
Forum: Camera board
Topic: How to order from non-UK countries?
Replies: 8
Views: 2365

Re: How to order from non-UK countries?

Just FYI: RS components are also taking orders, but the order page is a bit obfuscated. If you search for "Raspberry Pi" from their main page you will be taken here . There you will only see a "coming soon" banner for the camera, but if you click on "Personal use" beside the Raspi picture, as if you...
by kaos
Mon May 06, 2013 12:39 pm
Forum: Automation, sensing and robotics
Topic: Timer: Photocell or Distance Sensor ?
Replies: 13
Views: 5932

Re: Timer: Photocell or Distance Sensor ?

Re: Timing accuracy. I haven't any experience myself of timing critical projects, but from what I have read, this might be borderline if you need +/- 10mS accuracy, assuming a Raspi running Linux and without any additional circuitry. Hopefully somebody with more experience will chime in on this. If ...
by kaos
Sun Feb 24, 2013 1:15 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: X-Number/Unlimited Attached Sensors/I/O Daisy-chained
Replies: 8
Views: 4400

Re: X-Number/Unlimited Attached Sensors/I/O Daisy-chained

I agree that ethernet is attractive in that it is "ready to run"; standardized both in terms of equipment and protocols. And if we are only talking one, or even a few, Raspis per greenhouse, that would be an excellent solution. But that leaves the problem of connecting the various sensors and contro...
by kaos
Sun Feb 24, 2013 3:28 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: X-Number/Unlimited Attached Sensors/I/O Daisy-chained
Replies: 8
Views: 4400

Re: X-Number/Unlimited Attached Sensors/I/O Daisy-chained

I'm afraid I2C and SPI are short range standards that will be unreliable at a few meters, and flat out unusable at a few dozen. I really do think that RS485, or possibly CAN bus is the way to go. Some alternatives I have looked at: -RS232: Point-to point connection (no daisy chaining). Short range (...
by kaos
Thu Feb 21, 2013 11:47 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: X-Number/Unlimited Attached Sensors/I/O Daisy-chained
Replies: 8
Views: 4400

Re: X-Number/Unlimited Attached Sensors/I/O Daisy-chained

This strikes a chord. I have been mulling over options for a similar network, though in my case I was thinking of a home- rather than greenhouse automation, but I think the requirements might be very similar. First, re. Gordons suggestions of "more Raspis": This would be a good solution when either ...
by kaos
Wed Feb 20, 2013 1:28 am
Forum: Other projects
Topic: Pi Battery Trouble
Replies: 7
Views: 2069

Re: Pi Battery Trouble

If the screen takes 48W (4A at 12V), you won't be able to power it from a battery that delivers max. 24W (1.5A at 16V), no matter what kind of regulator you are using. You will either have to change to a bigger battery pack or find a less power hungry screen. What kind of screen is that anyway? 48W ...
by kaos
Fri Sep 21, 2012 5:37 pm
Forum: HATs and other add-ons
Topic: Webcam troubles: Turns off after a few frames
Replies: 12
Views: 8847

Re: Webcam troubles: Turns off after a few frames

I also find it unlikely that it is caused by drivers since I followed the simple webcam driver tutorial from the RPi wiki - which has been used and validated by many others. Do you have a link for that tutorial? I've just been traversing the Elinux wiki, but my search-fu seems to be lacking :( -- K...
by kaos
Mon Sep 17, 2012 8:24 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Temp measurement
Replies: 4
Views: 2359

Re: Temp measurement

As others have pointed out, this sensor uses the so called one-wire bus (which is actually at least two wires and preferably three, but that's marketing for you), not I2C. There is a one-wire library available for Raspi, and it is even included in Adafruit's own Occidentalis distro. And yes, a one-w...
by kaos
Mon Sep 17, 2012 7:43 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: ADXL345 Accelerometer
Replies: 51
Views: 29770

Re: ADXL345 Accelerometer

From the picture, it seems to be connected to P1-11, which is GPIO17. It seems to be an interrupt signal of some kind, and I expect the driver polls this pin when waiting for interrupt. Note that I haven't tried this module or driver.

--
Best regards,
Kári.
by kaos
Mon Sep 17, 2012 12:59 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: ADXL345 Accelerometer
Replies: 51
Views: 29770

Re: ADXL345 Accelerometer

Can anyone guess the pinout on the RPi GPIO header?
No need to guess: http://elinux.org/Rpi_Low-level_peripherals ;)

--
Best regards,
Kári.
by kaos
Mon Sep 17, 2012 12:27 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Injecting 12v on to the GPIO 5 volt pin to power RPi - don't
Replies: 16
Views: 3208

Re: Injecting 5v on to the GPIO 5 volt pin to power RPi - do

That voltage drop is across the polyfuse, which you bypass when powering the Raspi through the GPIO connector. That again means that you should set up your own protection when doing so, whether polyfuse, regular fuse or other.

--
Best regards,
Kári.
by kaos
Mon Sep 17, 2012 9:57 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Opto-isolator directly driven by GPIO port?
Replies: 21
Views: 24910

Re: Opto-isolator directly driven by GPIO port?

kaos wrote:it is not reverse leakage current over the C-E junction, but the base current of the transistor in operation
Edit: That, of course, should have been the C-B junction.
by kaos
Mon Sep 17, 2012 9:22 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Opto-isolator directly driven by GPIO port?
Replies: 21
Views: 24910

Re: Opto-isolator directly driven by GPIO port?

It is a PNP BJT connected as a high-side switch. Ah, mea culpa, I should have thought of that possibility. :oops: That, of course, explains the current figures; it is not reverse leakage current over the C-E junction, but the base current of the transistor in operation. I agree that this kind of se...
by kaos
Sun Sep 16, 2012 11:34 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Opto-isolator directly driven by GPIO port?
Replies: 21
Views: 24910

Re: Opto-isolator directly driven by GPIO port?

Actually, I find those leakage current figures surprisingly high. I would have expected something in the micro- or possibly even nano ampere range. How are you doing the test? Positive voltage to Vcc, negative voltage to Gnd, ammeter + to input and ammeter - to gnd?

--
Best regards,
Kári.
by kaos
Sun Sep 16, 2012 8:52 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Opto-isolator directly driven by GPIO port?
Replies: 21
Views: 24910

Re: Opto-isolator directly driven by GPIO port?

I have posted this link several times. http://arduino-direct.com/sunshop/index.php?l=product_detail&p=181 This is the relay I use on my RPi. Switching the port to output turns the relay on, switch back to input and it is off. Could not be simpler than that. Not the best idea in the world. There are...
by kaos
Sun Sep 16, 2012 8:06 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Injecting 12v on to the GPIO 5 volt pin to power RPi - don't
Replies: 16
Views: 3208

Re: Injecting 5v on to the GPIO 5 volt pin to power RPi - do

RG2 visually looks ok. Can I cut it off and solder another one in place? Yes. Well, unsolder rather than literally cut, to avoid damage to the circuit board, but it is certainly replaceable. You can get one from many sources; here is a link to Farnell http://export.farnell.com/on-semiconductor/ncp1...
by kaos
Tue Aug 28, 2012 10:29 pm
Forum: HATs and other add-ons
Topic: TP Link TL-WN722N working for G network, but not for N
Replies: 3
Views: 4774

Re: TP Link TL-WN722N working for G network, but not for N

...and 640K of memory should be enough for anyone. Sorry, couldn't resist :D Seriously, there are other advantages to using N networks over G, notably a *much* better range. Not that I can be of any help with getting it working, Linux noob that I am, but it is IMO certainly worth working on. -- Best...
by kaos
Sat Aug 25, 2012 12:12 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Using a 7" TFT
Replies: 8
Views: 6992

Re: Using a 7" TFT

I suspect that patching into the display at that point may be an uphill battle. You will have to find out what protocol the panel uses, what is the pinout of the connector, find a matching connector (maybe you can salvage it from the player) and find some method of connecting to one of the Raspi dis...
by kaos
Fri Aug 24, 2012 10:04 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Interfacing Raspberry Pi with RTC1307 without level shifter?
Replies: 31
Views: 5990

Re: Interfacing Raspberry Pi with RTC1307 without level shif

The device/board I am using is primarily designed for the arduino which is 5v and states in a highlighted box in the manual that it needs 5v and has pull up resistors to the SDA and SCL lines. If you do decide to connect this board directly to the Raspi, you should preferably remove those pull up r...
by kaos
Fri Aug 24, 2012 12:12 am
Forum: HATs and other add-ons
Topic: PiggyBack Board for Raspberry PI
Replies: 15
Views: 13012

Re: PiggyBack Board for Raspberry PI

Very interesting. Any chance of a link to that datasheet? The forum software has reduced it's size down below the point of legibility. Also, when will it be available? And of course, the most important question; what will it cost?

--
Best regards, Kári.
by kaos
Thu Aug 23, 2012 11:51 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Interfacing Raspberry Pi with RTC1307 without level shifter?
Replies: 31
Views: 5990

Re: Interfacing Raspberry Pi with RTC1307 without level shif

mahjongg: Thanks for your answer, my main concern is the SDA bus, because the DS1307, when "asked" from the R-Pi at 3.3vdc, will "answer" with TTL logic levels (usually 4volts high level) and this voltage exceeds the 3.3v R-Pi spec, then possibly frying my valuable R-Pi :shock: Nope, Mahjongg is ri...
by kaos
Thu Aug 23, 2012 9:16 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Connecting a 5V relay board
Replies: 20
Views: 14791

Re: Connecting a 5V relay board

Based on what you are saying, I am probably just using either discrete transistors or an array like the ULN2803 to directly drive relays. That's what I would do, certainly. One important tip; connect a diode in parallel with the relay coil, with cathode connected to positive (see f.x. schematic of ...
by kaos
Wed Aug 22, 2012 6:08 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Does PI support USB PS/2 keyboard + mouse??
Replies: 8
Views: 3898

Re: Does PI support USB PS/2 keyboard + mouse??

I think people may be confusing two things here. The first is an adapter to allow USB devices to be connected to PS/2 hosts. These used to be supplied with almost all keyboards and mice, back when USB was the hot new thing, and the odds were that your computer only had PS/2 connectors. These are (us...
by kaos
Wed Aug 22, 2012 5:48 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Connecting a 5V relay board
Replies: 20
Views: 14791

Re: Connecting a 5V relay board

I suspect that this particular board might give problems, if connected directly to the GPIO. Note that this board is "inverted"; an input has to be pulled low to allow current to pass from emitter to base in the (PNP type) transistor, which again allows current to flow from emitter to collector and ...

Go to advanced search