Go to advanced search

by BAStumm
Mon Aug 18, 2014 7:21 pm
Forum: Other projects
Topic: Touchscreens for Raspberry Pi
Replies: 105
Views: 186502

Re: Touchscreens for Raspberry Pi

matchbox-keyboard allows this auto popup feature when run in daemon mode... ie:

"matchbox-keyboard -d"

I am pretty sure some X related config file can be edited to auto run at startx.
by BAStumm
Mon Aug 18, 2014 5:00 pm
Forum: Other projects
Topic: Touchscreens for Raspberry Pi
Replies: 105
Views: 186502

Re: Touchscreens for Raspberry Pi

More on Dell e2014t touch monitor... So I can confirm that with the default driver chosen by Raspian that multipoint touch does not work. I've yet to find a solution to make the virtual keyboard pop up when a text input box is selected, but still hoping to find a way. I believe I will be using match...
by BAStumm
Sat Aug 16, 2014 4:19 am
Forum: Other projects
Topic: Touchscreens for Raspberry Pi
Replies: 105
Views: 186502

Re: Touchscreens for Raspberry Pi

I purchased this same dell e2014t monitor for use with the RPi. The touch does work, but not sure multi touch works. All I did was plug it in, no special drivers. Looking for advice on how to make raspian more touch friendly. And is there a way to calibrate the touch? It seems off a bit. How would I...
by BAStumm
Tue Jul 15, 2014 4:44 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2c read mutiple bytes[SOLVED]
Replies: 15
Views: 15614

Re: I2c read mutiple bytes

I don't use Python but I think the python read() function would work the same as the C function.
by BAStumm
Mon Jul 14, 2014 7:28 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2c read mutiple bytes[SOLVED]
Replies: 15
Views: 15614

Re: I2c read mutiple bytes

The "GET TEMPERATURE" command on a thermocouple device I'm using returns 4 bytes.

Code: Select all

  //setup i2c to mod-tc on 0x23
  if((fd = wiringPiI2CSetup(0x23)) < 0) {
    printf("I2CSetup Failed, %i\n", fd);
  }

  // GET_TEMP
  wiringPiI2CWrite(fd, 0x21);
  read(fd, temp, 4);
by BAStumm
Fri Jun 20, 2014 6:53 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO Buffer
Replies: 3
Views: 3872

Re: GPIO Buffer

The thing I linked to is 8 channels w/opto. If you need more than 4 channels then this option is cheaper than two of the other suggestion.
by BAStumm
Fri Jun 20, 2014 5:06 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO Buffer
Replies: 3
Views: 3872

Re: GPIO Buffer

Sounds like you want an opto-isolator board. Perhaps something like this... https://www.futurlec.com/Mini_Opto_Isolator.shtml

I use one for input and another for output. converts 3.3 to 5v.
by BAStumm
Wed Jun 18, 2014 7:16 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Programtically return address of device on i2c bus
Replies: 7
Views: 2375

Re: Programtically return address of device on i2c bus

How does this help? In order to use an i2c device you need to know what commands to issue it and what to expect back. You can always use i2cdetect to make sure the device is connected correctly and in your python code you can try to connect to an i2c device that you expect to be connected and return...
by BAStumm
Sat Jun 14, 2014 2:04 pm
Forum: Automation, sensing and robotics
Topic: controlling 230v from rPI - solution? pick holes at it!
Replies: 21
Views: 7935

Re: controlling 230v from rPI - solution? pick holes at it!

Optos are cheap, 8 channels for $5. In my (commercial) application I use optos between pi and ssr which is switching 277vac at 30 amps.
by BAStumm
Fri Jun 13, 2014 7:37 pm
Forum: Automation, sensing and robotics
Topic: Adding a 5v device to a A2D converter with a 3.3V reference
Replies: 9
Views: 3533

Re: Adding a 5v device to a A2D converter with a 3.3V refere

I believe the minimum reference voltage is 0.25 but low reference voltages affect linearity.
by BAStumm
Wed Jun 11, 2014 4:32 pm
Forum: Automation, sensing and robotics
Topic: Solar panel power output measurement with rpi
Replies: 19
Views: 6541

Re: Solar panel power output measurement with rpi

What kind of DC Voltage and Amperage will you be reading? What is the max you want to rate for vs typical.
by BAStumm
Wed Jun 11, 2014 3:59 pm
Forum: Automation, sensing and robotics
Topic: controlling 230v from rPI - solution? pick holes at it!
Replies: 21
Views: 7935

Re: controlling 230v from rPI - solution? pick holes at it!

SSR = safer, more reliable, less noise. Check e-bay. I saw a lot 10 SSR's for $8 but I didn't check the specs. Again, make sure you get zero cross with zero detection circuit. If you get a phase angle compatible version you will need to do zero cross detection yourself or phase angle fire it which i...
by BAStumm
Wed Jun 11, 2014 3:55 pm
Forum: Automation, sensing and robotics
Topic: Solar panel power output measurement with rpi
Replies: 19
Views: 6541

Re: Solar panel power output measurement with rpi

The insulation doesn't matter. Just watch the polarity of the donut, they only detect current flow in one direction. And I'm pretty sure there are current donuts for both AC and DC. Or are you wanting to read DC voltage?
by BAStumm
Wed Jun 11, 2014 3:20 pm
Forum: Automation, sensing and robotics
Topic: Solar panel power output measurement with rpi
Replies: 19
Views: 6541

Re: Solar panel power output measurement with rpi

RPi has no analog input, you need an ADC expansion board. What do you want to measure? Hall Effect Sensor measures current. Edit: I should have read more... Get a hall sensor that outputs a mV signal proportional to your max amps. You should be able to find a sensor that is around 40mV/Amp. That wil...
by BAStumm
Wed Jun 11, 2014 3:17 pm
Forum: Automation, sensing and robotics
Topic: controlling 230v from rPI - solution? pick holes at it!
Replies: 21
Views: 7935

Re: controlling 230v from rPI - solution? pick holes at it!

Never heard of a solid state relay that is i2c. I think you want to add an i2c i/o expansion board in future then use gpio's to trigger the ssr.
by BAStumm
Wed Jun 11, 2014 3:15 pm
Forum: Automation, sensing and robotics
Topic: controlling 230v from rPI - solution? pick holes at it!
Replies: 21
Views: 7935

Re: controlling 230v from rPI - solution? pick holes at it!

Yep, solid state relays... I'm working on a similar application. I'd also put an opto-isolator breakout board between pi and SSR. use the opto to change from 3.3 to 5vdc (not necessary if short wire run). Most SSR's will switch from 3vdc. At least the ones I use do. Pick an SSR with zero cross detec...
by BAStumm
Wed Jun 11, 2014 12:59 pm
Forum: Automation, sensing and robotics
Topic: SHT10 shows very high (relative) humidity (in soil)
Replies: 22
Views: 13009

Re: SHT10 shows very high (relative) humidity (in soil)

You can test accuracy of the sensor with a salt solution... Table salt is sodium chloride (NaCl), which provides 75% RH at room temperature ~70F/20C. Take a cup and put a few tablespoons of table salt in it. Add water to make a slurry, it will look like wet sand so not much water maybe 1 tablespoon ...
by BAStumm
Tue Jun 10, 2014 8:12 pm
Forum: Automation, sensing and robotics
Topic: SHT10 shows very high (relative) humidity (in soil)
Replies: 22
Views: 13009

Re: SHT10 shows very high (relative) humidity (in soil)

I suspect the sensor is contaminated. Have you tried getting readings from air instead of in the soil? Sensirion (the manufacturer of the sensor being used on whatever breakout board you have) have suggested to me previously to bake the sensor for a few hours to remove contamination. I'd have to rev...
by BAStumm
Mon Jun 09, 2014 8:41 pm
Forum: Automation, sensing and robotics
Topic: SHT10 shows very high (relative) humidity (in soil)
Replies: 22
Views: 13009

Re: SHT10 shows very high (relative) humidity (in soil)

For some reason my C1, C2 and C3 values are different... not sure why. It's been a couple years since I worked on that project.

C1 = -4.0
C2 = .0405
C3 = -2.8e-6
by BAStumm
Mon Jun 09, 2014 8:15 pm
Forum: Automation, sensing and robotics
Topic: SHT10 shows very high (relative) humidity (in soil)
Replies: 22
Views: 13009

Re: SHT10 shows very high (relative) humidity (in soil)

Sorry, I am not a python guy... I code in C. Here is what I'm using, for what it's worth... One thing to check is that you are reading 14 bit temp and 12 bit hum values... not 12 and 8. /* * dlp_read_hum * - read humidity from DLP-TH1 sensor */ int dlp_read_hum(_dlp_th1 *dlp) { unsigned char msb, ls...
by BAStumm
Mon Jun 09, 2014 2:50 pm
Forum: Automation, sensing and robotics
Topic: SHT10 shows very high (relative) humidity (in soil)
Replies: 22
Views: 13009

Re: SHT10 shows very high (relative) humidity (in soil)

I've used this sensor before but it has been a while. I could look through my code and compare to yours if you want. How are you doing the conversion to come up with the humidity value. Can you share the code?
by BAStumm
Mon Jun 09, 2014 2:32 pm
Forum: Automation, sensing and robotics
Topic: drive multiple heavy duty stepper motors
Replies: 16
Views: 22527

Re: drive multiple heavy duty stepper motors

The Big Easy Driver might give you enough torque but if it where me I'd look at Gecko Drivers and NEMA 34 stepper motors. I would also consider a higher DC voltage, somewhere around 30 to 48 VDC. The regular easy driver at sparkfun won't give you the current (and thus the torque) you want for millin...
by BAStumm
Fri Jun 06, 2014 10:23 pm
Forum: C/C++
Topic: wiringPi i2c help
Replies: 9
Views: 8597

Re: wiringPi i2c help

I have a couple of abelelectronics ADC-Pi's and they work very well. The wiringPi library had a bug or two in it but I believe it has since been sorted. It's sorted on my local machine/Pi anyway and Gordon was a major help with that.
by BAStumm
Fri Jun 06, 2014 9:46 pm
Forum: C/C++
Topic: wiringPi i2c help
Replies: 9
Views: 8597

Re: wiringPi i2c help

The mod-tc-mk2 has a pic16f1503 attached to a max31855 (thermocouple) chip. The pic uses clock stretching. I have to slow the RPi i2c clock to 80k or less for things to work. Default on the Pi is 100k. And to allow any decent amount of time for ISR handling at the pic I have to slow it even more or ...

Go to advanced search