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by dkossman
Mon Sep 05, 2016 9:29 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO to SainSmart 4-channel relay board, transistors needed?
Replies: 11
Views: 29540

Re: GPIO to SainSmart 4-channel relay board, transistors nee

15ma is what is required to drive each of the relay coils. However the actual input current to each of the board's IN1... IN8 inputs is about 0.45ma when pulling them low. I just measured it on a typical 8 relay board off eBay similar to the one being discussed. Thus its perfectly safe to drive dire...
by dkossman
Mon Apr 28, 2014 1:37 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO to SainSmart 4-channel relay board, transistors needed?
Replies: 11
Views: 29540

Re: GPIO to SainSmart 4-channel relay board, transistors nee

just found this on ebay. looks like you can jumper it to trigger either high or low. I've asked the seller for a schematic - need to confirm that if i hook it up to 5V that it won't feed back to the Pi's 3.3v GPIO pins. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=251486573020 anyone familiar ...
by dkossman
Fri Dec 20, 2013 5:47 pm
Forum: Troubleshooting
Topic: DS18B20 + Camera module; modprobe breaks camera
Replies: 25
Views: 20718

Re: DS18B20 + Camera module; modprobe breaks camera

Same problem here - also using a couple of 1-wire temperature probes on GPIO7 (BCM GPIO4). It was all working fine up until a couple months ago, but must have broken in one of the updates.

If anyone finds a solution, please let us know...

thanks!
by dkossman
Thu Aug 29, 2013 3:43 pm
Forum: Camera board
Topic: Alternatives or replacements for camera flex cable?
Replies: 149
Views: 132776

Re: Alternatives or replacements for camera flex cable?

Notwithstanding the comments above, I am looking for 2 meters - can you supply these, and at what cost (US$)?. My understanding from previous posts is that longer lengths do work (using a combo of the original type of flex cable, adapter, and regular ribbon cable) so i'd imagine that a straight flex...
by dkossman
Thu Aug 08, 2013 9:31 pm
Forum: Camera board
Topic: Alternatives or replacements for camera flex cable?
Replies: 149
Views: 132776

Re: Alternatives or replacements for camera flex cable?

perhaps this is a dumb question, but i'll ask anyway - the kit contents for the bitwizard extender, according to their web site: - 2 FPC to 2x8pin header adapter boards - 2 16-way IDC connectors - 1 15cm opposite-side contacts FPC cable why not just use a long FPC cable? is there some technical reas...
by dkossman
Wed Aug 07, 2013 1:23 am
Forum: Python
Topic: WiringPython - WiringPi for Python
Replies: 205
Views: 64166

Re: WiringPython - WiringPi for Python

Hi Gordon, thanks for the detailed reply - much appreciated. It all makes sense now. I had actually taken another look at it last night and worked out a similar solution, though i used the default range of 1024 rather than 2000 so ended up with a divisor of 375. For some reason it wasn't clear to me...
by dkossman
Mon Aug 05, 2013 10:24 pm
Forum: Python
Topic: WiringPython - WiringPi for Python
Replies: 205
Views: 64166

Re: WiringPython - WiringPi for Python

Hi Gordon, I think I've got a similar problem - I am trying to run a small R/C type servo using hardware PWM with wiringPi and i believe it is looking for a 50hz frequency with pulse widths from 1 to 2 msecs to rotate 0 - 180 degrees. e.g. something like: http://www.ermicro.com/blog/wp-content/uploa...
by dkossman
Sat Apr 27, 2013 4:31 pm
Forum: Automation, sensing and robotics
Topic: PWM outputs
Replies: 20
Views: 58184

Re: PWM outputs

The "driver" is an N-channel power mosfet - not sure how this motor (it's a brushed DC) would react to more versus fewer transitions. I've been trying to find pictures of a "balanced" PWM signal to compare it to mark/space, but haven't seen anything. Also - any idea what the default output frequency...
by dkossman
Fri Apr 26, 2013 11:47 pm
Forum: Automation, sensing and robotics
Topic: PWM outputs
Replies: 20
Views: 58184

Re: PWM outputs

Sorry if this is slightly off-topic - I'm planning to use the Pi's hardware GPIO pin to drive a 12vdc motor (using a MOSFET) foe a small peristaltic pump. There appear to be two PWM modes available - Balanced and Mark/Space. Anyone know what the advantages/disadvantages are of these two modes? I've ...
by dkossman
Sun Mar 10, 2013 6:53 am
Forum: C/C++
Topic: I2C LCD using C
Replies: 53
Views: 39245

Re: I2C LCD using C

Hi Jan, I'd suggest: 1. git clone https://github.com/symptog/rpi_lcd.git 2. set this up as a library: a. change all instances in the code of #include "xxx.c" to #include "xxx.h" b. change the Makefile to something like: SRCS = lcd.c mcp.c rpii2c.c OBJS = $(patsubst %.c, %.o, $(SRCS)) HDRS = $(patsub...
by dkossman
Sun Mar 03, 2013 12:05 am
Forum: C/C++
Topic: I2C LCD using C
Replies: 53
Views: 39245

Re: I2C LCD using C

The code at https://github.com/symptog/rpi_lcd was updated about a week ago in response to the issue that I posted on github. It is easily cleaned up to remove the C includes (see my comments to the closed issue titled "Release notes?"). I've been using it with the Adafruit 16x2 I2C backpack and it ...
by dkossman
Fri Feb 22, 2013 12:57 am
Forum: C/C++
Topic: send email from a C program?
Replies: 12
Views: 14086

Re: send email from a C program?

Thanks, everyone, for the suggestions. I ended up using libesmtp. It's a C library, which is what I wanted, there are some nice examples, and it turned out to be really easy to use. It does outgoing mail only, which is all I need (for now). You just point it at your friendly local email provider's s...
by dkossman
Sat Feb 16, 2013 7:40 pm
Forum: C/C++
Topic: I2C LCD using C
Replies: 53
Views: 39245

Re: I2C LCD using C

Thanks for the pointer. Have you actually tried this with the Adafruit 16x2 I2C backpack? I couldn't find any mention of it in the hardware section of the lcdproc site.
by dkossman
Sat Feb 16, 2013 1:40 am
Forum: C/C++
Topic: I2C LCD using C
Replies: 53
Views: 39245

Re: I2C LCD using C

Thanks for looking into it - not sure that I want to remove i2c-dev-tools - that will break my ability to build my existing code (which includes support for an I2C-based ADS1115 a/d converter). I've posted an issue on his github project, I'll let you know if I hear anything back...

Don
by dkossman
Thu Feb 14, 2013 6:23 am
Forum: C/C++
Topic: I2C LCD using C
Replies: 53
Views: 39245

Re: I2C LCD using C

Thanks! but unhappily, it doesn't seem to want to build - lots of errors. Haven't had time to dig in to figure out why. There's no discussion, few comments and no release notes. Maybe it is for a different flavor of Linux than Raspbian? I guess I'll need to create a github account and post some ques...
by dkossman
Wed Feb 13, 2013 10:33 pm
Forum: C/C++
Topic: send email from a C program?
Replies: 12
Views: 14086

Re: send email from a C program?

Gordon, thanks for the pointer to libESMTP - this seems like a good bet, assuming i can just point it at the gmail SMTP server and use a gmail account to authenticate. Since I use gmail for my own mail, and I just need the Pi to send the emails to me, I should be good in terms of not relaying (I thi...
by dkossman
Wed Feb 13, 2013 6:30 pm
Forum: C/C++
Topic: send email from a C program?
Replies: 12
Views: 14086

send email from a C program?

I've got a C program running on my Pi (Raspbian) monitoring and controlling an aquarium. I'd like to have it send me email alerts when specific out-of-limit conditions are detected. I'd also like (if possible) to avoid installing anything like "sendmail" or "exim", with its attendant complexities, o...
by dkossman
Mon Feb 11, 2013 4:49 pm
Forum: C/C++
Topic: I2C LCD using C
Replies: 53
Views: 39245

Re: I2C LCD using C

I just took a look at the product page and documentation you linked, and it wasn't immediately clear whether the Bitwizard board is functionally identical to the Adafruit one - any idea if this is so? Is the Bitwizard device also based on the MPC23017 expander?

thx
Don
by dkossman
Mon Feb 11, 2013 2:15 am
Forum: C/C++
Topic: I2C LCD using C
Replies: 53
Views: 39245

Re: I2C LCD using C

I have pretty much the same problem. I am reasonably fluent in C (though I hadn't coded for many years prior to getting a PI) but don't know Python, and C++ makes my brain hurt. If you make any progress, let me know, I'll do the same by posting here... I think (as Gordon has already mentioned) its g...
by dkossman
Fri Feb 08, 2013 7:22 pm
Forum: C/C++
Topic: I2C LCD using C
Replies: 53
Views: 39245

Re: I2C LCD using C

One more bit of info - the display works fine using the Adafruit Python code...
by dkossman
Fri Feb 08, 2013 6:53 am
Forum: C/C++
Topic: I2C LCD using C
Replies: 53
Views: 39245

Re: I2C LCD using C

Thanks for posting this - I updated Raspbian and updated to the latest WiringPi, but when i run your program with my Adafruit 2x16 I2C LCD backpack, it turns on the backlight, and lights up all the bits in all 16 characters in the first row, and thats it. Any idea what might be wrong?

Don
by dkossman
Wed Feb 06, 2013 8:16 am
Forum: C/C++
Topic: I2C LCD using C
Replies: 53
Views: 39245

Re: I2C LCD using C

Which Adafruit python scripts are you using? can you provide details?
Looks like you put them here on your Pi: "/home/rasppi/src/py_scripts".

thx
by dkossman
Sun Feb 03, 2013 10:52 pm
Forum: C/C++
Topic: I2C LCD using C
Replies: 53
Views: 39245

Re: I2C LCD using C

spbecker wrote:This is just the sort of thing I was looking for! The Adafruit Python scripts are OK to make sure things work, but the language gives me the creeps. I'm going to give it a shot at creating a C library for talking to the LCD shield.
Please keep us posted on your progress!
by dkossman
Sat Jan 26, 2013 6:23 pm
Forum: C/C++
Topic: I2C LCD using C
Replies: 53
Views: 39245

Re: I2C LCD using C

Hi Gordon, thanks very much for the detailed reply. I've been using WiringPi to talk to an Atlas Scientific ORP board on the Pi's serial port, so have the code installed and working. I'll dig into this and see how it goes... FYI, I also just posted a query here (http://blog.lincomatic.com/?p=956 ) r...
by dkossman
Sat Jan 26, 2013 3:22 am
Forum: C/C++
Topic: I2C LCD using C
Replies: 53
Views: 39245

Re: I2C LCD using C

I have the same intent - i'm an C programmer and am trying to avoid Python :-). I also need to integrate the display with other C code that I'm writing, which talks to a device on the serial port as well as to an I2C analog-to-digital converter. I found these, but both are for the Arduino: https://g...

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