Raspberry Pi Forums

joan

An an interim measure why not change the serial baud rate? They both support 115200 which is 12 times faster.

joan

Buy a bigger battery?

More seriously - what sevices will you be using in this low power mode? Perhaps other boards may be better suited to your application.

joan

No problems with power at the levels you are talking about. You can take 30mA from the 3V3 supply and several 100mA from the 5V supply (assuming you are powering the Pi through it's micro usb socket power supply.

joan

I have continued my experiments with PWM for motors/leds and servos. I found memory <> memory DMA unreliable (memory <> peripheral memory seems fine) so abandoned that as a way of triggering servo pulses. Currently I'm triggering the servo pulses using a timer tick (the pulse length is timed by DMA)...

joan

Something installed with apt-get can be removed with apt-get.

e.g. to reverse

sudo apt-get install package

do

sudo apt-get remove package

joan

I have three of those boards. One I use with the Pi, the other two I use with TI launchpads. The Pi and launchpads are 3V3 devices. I've not noticed any problems controlling motors via that board.

joan

raspberrypiguy1 wrote:Does it have to be 12v? My motors are 5v?

Thanks

The Raspberry Pi Guy

No, the voltage isn't important. The spec say 5-35 for that pin. I've powered the module directly from a 14.8V lipo and through a 5V BEC.

joan

: img_2241a.jpg (56.05 KiB) Viewed 12125 times

Motor controller board in situ.

joan

Choose four gpios. Name the gpio A, B, C, D. Connect gpio A to IN1, B to IN2, C to IN3, D to IN4. Connect the motor power source positive (battery?) to +12V power. Connect motor power source negative to power ground. Connect Raspberry Pi ground to power ground. Connect motor leads to terminals. Set ...

joan

Nice and simple.

I've used the Pi to drive motors using this board.

http://www.ebay.co.uk/itm/140743762410

joan

I'd go with the ULN2003A as a more flexible solution. img_2726a.jpg The white wire connected to the positive rail represents a gpio. Touching the other end to pin1 of the ULN2003A (bottom left of chip) switches the motor on. To protect the Pi from flyback voltages it is important to connect ULN2003A...

joan

Does it look damaged or not as new? If not try running it.

joan

It's just a tad over. I think the spec suggest 16 mA (search http://elinux.org/Rpi_Low-level_peripherals for 16 mA). I drive a laser pen rated at 20mA from a gpio but I have a rather relaxed attitude to frying a Pi gpio. You need a resistor in series with the LED anyhow. Just choose one which limits...

joan

rgh wrote:...Maybe we should move this off the ultrasonics thread

I've sent a PM.

joan

... Motor driver: http://www.ebay.co.uk/itm/300789874773?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 Does anyone think this motor driver will work? ... I don't think so. The chip is probably a ULNA2003 which is fine for stepper motors but will not drive a DC motor forwards/backwards as a H b...

joan

Yes. I'm doing so at the moment.

joan

Yes, you can, actually all GPIO's default to being standard GPIO's except the UART pins, (and even these can be reprogrammed) all the secondary functions only come into play when the pins are programmed for their secondary function, and also any pullups and pulldowns are programmable. The revision ...

joan

I think by default mysql only accepts local connections. Have a look in /etc/mysql for a file called my.cnf See if it has a line like bind-address = 127.0.0.1 if it does then comment it out by putting a # at the start of the line and restart mysql sudo /etc/init.d/mysql restart Those instructions wo...

joan

... Anyway, to your question.. servoblaster only needs four DMA control blocks for a single PWM, two to set the output high or low, two to implement the delays. If you want to change the pulse width you just need to tweak the two delay counts. The driver for this sensor has hundreds of DMA control ...

joan

You could try a manual install of 4.7 sudo apt-get install gcc-4.7 However the system might still preferentially use 4.6. I think I'd temporarily pretend that 4.6 is 4.7 to see if that gets you any further in the installation process. Try sudo ln -s -T /usr/bin/gcc /usr/local/bin/gcc-4.7 Also you sh...

joan

I know nothing of Ruby. Can't you open/read/write/close files in Ruby? If you can then use the same methods to open/read/write/close the I2C file. If Ruby can't work with files then I'd suggest you use a different programming language.

joan

It appears to be complaining about the version of gcc.

What does gcc --version report?

joan

A cut-and-paste of the command you have issued and the system's response may be helpful.

joan

Just checked by looking out the window.

Nope, no flying pigs.

You may have unreasonable expectations.

joan

There is a proper i2c device. I'd use that as it's likely to be much simpler than rolling your own with wiringPi.

If you use the device I2C is accessed like any other file.

Have a look at http://www.raspberrypi.org/phpBB3/viewt ... 19#p191519

Search found 14956 matches

Re: Raspberry Pi to Arduino -> i2c or serial

Re: Ultra low power mode?

Re: I2C: How to connect multiple devices.

Re: Driving multiple servos from the RaspberryPi

Re: Uninstalling things

Re: Motor Controller Interface Board?

Re: Motor Controller Interface Board?

Re: Motor Controller Interface Board?

Re: Motor Controller Interface Board?

Re: Motor Controller Interface Board?

Re: Relays and Motors

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Re: Ultra cheap ultrasonics, and a bit of a challenge

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Re: C compiler cannot create executables

Re: C compiler cannot create executables

Re: 256MB Pi -> 512MB Pi

Re: Use I2C with Ruby