Go to advanced search

by Richard-TX
Mon Mar 26, 2018 5:36 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Accessing permission to open port /dev/ttyS0 for Serial communication
Replies: 8
Views: 14452

Re: Accessing permission to open port /dev/ttyS0 for Serial communication

I believe you are bumping heads with udev. Try creating a file in /etc/udev/rules.d with the suffix .rules, e.g. local.rules, and add a line like this to it: ACTION=="add", KERNEL=="ttyS0", MODE="0666" As a FYI, I have had timing issues with the serial port hardware on the Rpi so your mileage may va...
by Richard-TX
Mon Mar 26, 2018 5:28 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Multiple I2C Sensors with Same address (no peripherals/multiplexer)
Replies: 3
Views: 1479

Re: Multiple I2C Sensors with Same address (no peripherals/multiplexer)

Adding more i2c buses is yet another option as Joan said.

Enjoy!
by Richard-TX
Mon Mar 26, 2018 5:18 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Multiple I2C Sensors with Same address (no peripherals/multiplexer)
Replies: 3
Views: 1479

Re: Multiple I2C Sensors with Same address (no peripherals/multiplexer)

You have to order the correct pressure sensors. There are a 6 different addresses available depending on what you order. See page 13 of the datasheet and look at the output type. You can order devices with the following addresses - 0x28, 0x38, 0x48, 0x58, 0x68, and 0x78 There is no cheating on somet...
by Richard-TX
Wed Mar 21, 2018 6:22 am
Forum: Raspbian
Topic: Stretch slow - much slower than Jessie
Replies: 7
Views: 4049

Stretch slow - much slower than Jessie

Stretch is noticeably slower than Jessie or wheezy. There is no debating that fact. The only question is why and how could this have passed QC? Platform - Raspberry B New SD Card - Samsung 32G EVO Just doing an aptitude install of ksh and removal of wolfram-engine was painful. The GUI desktop was pa...
by Richard-TX
Sun Sep 11, 2016 11:43 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: A different way to mount a Pi Zero
Replies: 1
Views: 830

Re: A different way to mount a Pi Zero

When I needed a pump/irrigation controller, I went with a Teco PLR. It would up being cheaper than a Pi based solution.

I do use a Pi in my shop as both a air valve controller and music source.
by Richard-TX
Sun Jul 03, 2016 11:44 am
Forum: Automation, sensing and robotics
Topic: Replacing old TECO SG2 with RPi
Replies: 1
Views: 1307

Re: Replacing old TECO SG2 with RPi

I apologize for dredging up this old post. http://chipenergy.com/images/IMG_2807.JPG Please clean up that wiring. I know you inherited it, but that is pretty horrible. At least add a few terminal blocks and get rid of that 115 volt plug and receptacle. I have had a few years experience with the SG2 ...
by Richard-TX
Sun Apr 17, 2016 7:17 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Connect 10 buttons. How ?
Replies: 6
Views: 1362

Re: Connect 10 buttons. How ?

I have found that a two pronged approach (software and hardware) is superior to any single approach when mitigating bounce issues.
by Richard-TX
Sun Apr 17, 2016 4:39 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C Address , 7-segment
Replies: 3
Views: 1242

Re: I2C Address , 7-segment

Without at least a description of how you are interfacing the 7 segment display to the I2C bus, of at least the device's number, no one can help you. Personally I would use multiple BCD to 7 segment drivers and a MCP23017 to drive the display. It makes life a lot easier. Write a 8 and "8" is display...
by Richard-TX
Sun Apr 17, 2016 4:16 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SOLVED: I2C clock speed / performance
Replies: 13
Views: 13514

Re: SOLVED: I2C clock speed / performance

To get high speed from the I2C bus connected device a few things have to be done. - set the I2c clock (bus) speed as high as the device can handle it. In the case of the MPU6050, the clock speed is limited to 400KC. Unless you get the SPI version, that is as fast as it will go. The SPI version is ra...
by Richard-TX
Sun Apr 17, 2016 4:06 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Connect 10 buttons. How ?
Replies: 6
Views: 1362

Re: Connect 10 buttons. How ?

Ah! Very nice - thanks. So I just need MCP23017 and that's it.... Yup. That is it as far as hardware is concerned. Since you are going to be using pushbuttons, there is a little bit more to interfacing them to the MCP23017. You will likely have to add some debounce components to the input lines and...
by Richard-TX
Sun Apr 17, 2016 4:01 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: More than 2 SPI slaves on RPI3
Replies: 7
Views: 4067

Re: More than 2 SPI slaves on RPI3

Depending on the device connected it is possible to have up to 8 devices per CS line. The MCP23S16 is one such device.
by Richard-TX
Tue Feb 23, 2016 8:41 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Car Light Control
Replies: 5
Views: 2458

Re: Car Light Control

Doing your own lighting controls can be rife with pitfalls. On modern cars things like lamp current for headlights, brake lights, parking lights and running lights are monitored. On Eurospec cars, fog lamp current is also monitored on some vehicles. That means that the instant wires are cut, error c...
by Richard-TX
Tue Feb 23, 2016 5:21 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: MCP3008 fluctuation
Replies: 5
Views: 1871

Re: MCP3008 fluctuation

Any ADC will have some fluctuations but in your case you left the line open which means that internal chip leakage or AC leakage from nearby mains will cause the ADC readings to vary all over the place. Under normal steady DC conditions the value returned will be plus or minus the least significant ...
by Richard-TX
Sat Jun 27, 2015 5:38 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: 8x8 matrix with 1 MCP23017
Replies: 6
Views: 1810

Re: 8x8 matrix with 1 MCP23017

You can have 8 MCP23S17 chips on each CS pin for a total of 16 chips per Pi. I have done it.
by Richard-TX
Thu May 21, 2015 5:26 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Expand over 700 IOs
Replies: 6
Views: 1400

Re: Expand over 700 IOs

700 inputs and 50 outputs? That is easy! How about 1024 I/O ports? Get 64 mcp23017 chips and two i2c mux. You will then have 1024 i/o ports. http://dsscircuits.com/sale/product/dssc0107 Wire up one mux and 32 mcp23017 chips to one I2C bus and the rest to the other I2c bus. If you need a few more, ge...
by Richard-TX
Sat May 16, 2015 10:20 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C MCP23017 crashes
Replies: 7
Views: 1604

Re: I2C MCP23017 crashes

Why would you buy a counterfeit from China ? Genuine MCP23017 chips are available from Digikey for $1.20 each in lots of 10. Cheap shipping too. The are $1 each in lots of 25 pcs. http://www.digikey.com/product-search/en?pv69=80&FV=fff40027%2Cfff80312&k=mcp23017&mnonly=0&newproducts=0&ColumnSort=0&p...
by Richard-TX
Mon Mar 23, 2015 12:14 pm
Forum: Automation, sensing and robotics
Topic: Controlling a 2kW heat plate
Replies: 10
Views: 2463

Re: Controlling a 2kW heat plate

if I were you I would first get rid of the mechanical relay and use a solid state relay. Normal relays will drive you nuts with the constant click-click-click.
by Richard-TX
Wed Mar 11, 2015 5:13 am
Forum: Troubleshooting
Topic: Auto login issue
Replies: 7
Views: 1522

Re: Auto login issue

Whether or not you login as root or as another user doesn't matter. Each has it's security drawbacks. Personally, I lock the pi account, assign the root account a good password and then create my own account. WHen I need root, I use su.
by Richard-TX
Mon Mar 09, 2015 4:22 am
Forum: General discussion
Topic: Can anyone help me with an acceptable relay (HVAC/Chiller)?
Replies: 15
Views: 2619

Re: Can anyone help me with an acceptable relay (HVAC/Chille

Why would you use a monsterous relay like that when a 40 amp solid state relay would work perfectly and noiselessly too.

Hook up the SSR directly to a GPIO pin and ground and go.
by Richard-TX
Mon Mar 09, 2015 4:11 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: i2c shows nothing on my rpi b2 (solved)
Replies: 2
Views: 930

Re: i2c shows nothing on my rpi b2 (solved)

When using raspi-config, there is a set procedure to enable the I2C bus.

The steps are.

1 - enable device tree
2 - enable i2c.

If you previously disabled device tree, the you have to re-enable i2c after re-enabling the device tree.
by Richard-TX
Thu Mar 05, 2015 12:09 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SOLVED: pi2, i2c0 and Wheezy
Replies: 26
Views: 11550

Re: pi2, i2c0 and Wheezy

Updating the firmware fixes the issue. Now I2C-0 is alive.

I am marking this issue solved.
by Richard-TX
Wed Mar 04, 2015 1:46 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SOLVED: pi2, i2c0 and Wheezy
Replies: 26
Views: 11550

Re: pi2, i2c0 and Wheezy

Here is the corrected code. echo 28 | sudo tee /sys/class/gpio/export echo 29 | sudo tee /sys/class/gpio/export echo in | sudo tee /sys/class/gpio/gpio28/direction echo in | sudo tee /sys/class/gpio/gpio29/direction if running from a root shell or rc.local echo 28 > /sys/class/gpio/export echo 29 > ...
by Richard-TX
Tue Mar 03, 2015 2:43 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SOLVED: pi2, i2c0 and Wheezy
Replies: 26
Views: 11550

Re: pi2, i2c0 and Wheezy

Thanks very much Phil.

I did notice the semi-mirroring of i2c0. I say semi because there is a difference in the two. I am not sure why. Maybe because I didn't have any devices connected to 27/28.
by Richard-TX
Sun Mar 01, 2015 8:01 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: mcp23017
Replies: 2
Views: 724

Re: mcp23017

bus.write_byte_data(address,regaddr,value) address = i2c address of mcp23017 (0x20, etc) where regaddr = 0x13 or 0x14 0x13 = port "B" 0x14 = port "A" value = 8 bit value for turning on/off outputs. You can use the "&" function to turn bits on or off. port 1 - 0x01 port 2 = 0x02 port 3 = 0x04 port 4 ...

Go to advanced search