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by rgrbic
Wed Jul 09, 2014 5:26 pm
Forum: Automation, sensing and robotics
Topic: Powerful little Stepper Motor
Replies: 13
Views: 3752

Re: Powerful little Stepper Motor

The link is useful info, but the stepper driver mentioned is in no way suitable for the NEMA 3 stepper you linked earlier that is rated for 6.5A per phase. If you want lots of torque you need a high current driver. Good point, the driver from the page uses uln2003 which can provide around 500 mA pe...
by rgrbic
Wed Jul 09, 2014 12:09 pm
Forum: Automation, sensing and robotics
Topic: Powerful little Stepper Motor
Replies: 13
Views: 3752

Re: Powerful little Stepper Motor

Here you can find example of unipolar stepper motor driver and how to control it with RPi.
by rgrbic
Wed Jul 09, 2014 9:45 am
Forum: Automation, sensing and robotics
Topic: Powerful little Stepper Motor
Replies: 13
Views: 3752

Re: Powerful little Stepper Motor

Why do you want to use stepper motor? Is there any particular reason?
For the drill I would use universal motor.
by rgrbic
Tue Jul 08, 2014 10:41 pm
Forum: Automation, sensing and robotics
Topic: Remote stepper motor control
Replies: 0
Views: 743

Remote stepper motor control

I see that many people ask about stepper motor control with Raspberry Pi. Here we explain how to control stepper motor with RPi over webpage. Article is not yet finished, description of client side is missing. You can see how it works in this youtube video. Hope that this information can help someon...
by rgrbic
Sun Jul 06, 2014 7:11 pm
Forum: Automation, sensing and robotics
Topic: electric motor actuation
Replies: 4
Views: 1719

Re: electric motor actuation

Inductive proximity sensor usually works with higher voltage than 3.3V so you will need power supply and some signal conditioning before connecting to RPi GPIO.
by rgrbic
Fri Jul 04, 2014 7:28 am
Forum: Python
Topic: How to update values from python to a web page?
Replies: 7
Views: 11957

Re: How to update values from python to a web page?

Check this site. Here, the sensor readings are sent to webpage periodically using websocket.
by rgrbic
Thu Jul 03, 2014 8:24 pm
Forum: Troubleshooting
Topic: No signal. DVI to HDMI adapter [solved]
Replies: 7
Views: 9126

Re: No signal. DVI to HDMI adapter

AFAIK you can connect RPi to monitor with HDMI -> DVI cable only if the monitor input is DVI-D. Otherwise, you have to use active converter to convert digital to analog signal (for example HDMI to VGA). In that case you have to force HDMI output in config file because RPi does not see any digital de...
by rgrbic
Thu Jul 03, 2014 12:28 pm
Forum: Graphics, sound and multimedia
Topic: Help needed: Using GPIO to switch off amplifier circuit
Replies: 10
Views: 3239

Re: Help needed: Using GPIO to switch off amplifier circuit

You can turn devices on/off with a relay.
by rgrbic
Tue Jul 01, 2014 3:04 pm
Forum: Automation, sensing and robotics
Topic: Yet more DHT22 sensor code
Replies: 101
Views: 81007

Re: Yet more DHT22 sensor code

i don't think there can be a different reason to be there if not to be a pull up resistor, isn't it? :) and what about the other smd thing? there's nothing written on it.. can it be a fuse? i can't see where it's connected :( probably capacitor between supply pins this is good :) i had never seen a...
by rgrbic
Tue Jul 01, 2014 11:18 am
Forum: Automation, sensing and robotics
Topic: Yet more DHT22 sensor code
Replies: 101
Views: 81007

Re: Yet more DHT22 sensor code

pattagghiu wrote:i don't think there can be a different reason to be there if not to be a pull up resistor, isn't it? :)
and what about the other smd thing? there's nothing written on it.. can it be a fuse? i can't see where it's connected :(
probably capacitor between supply pins
by rgrbic
Tue Jul 01, 2014 11:12 am
Forum: Automation, sensing and robotics
Topic: Yet more DHT22 sensor code
Replies: 101
Views: 81007

Re: Yet more DHT22 sensor code

Connect + to 3V3 and - to ground. Connect OUT to a gpio. Set the gpio as read with pull-up/downs off. If the gpio reads high you may not need a pull-up. Can you read the resistor value. I think about 5k is specified for the pull-up. it seems to me that there's a "512" written on the embedded resist...
by rgrbic
Mon Jun 30, 2014 7:15 am
Forum: Troubleshooting
Topic: Random Crashes and Freezes
Replies: 8
Views: 2025

Re: Random Crashes and Freezes

I agree, probably problems with the power supply. I had some cheap samsung galaxy charger and my RPi often crashed when working on it.
by rgrbic
Mon Jun 30, 2014 6:14 am
Forum: Beginners
Topic: Pressure Sensors
Replies: 5
Views: 1011

Re: Pressure Sensors

I would try hacking some cheap bathroom scale
by rgrbic
Sun Jun 29, 2014 9:15 am
Forum: Automation, sensing and robotics
Topic: Yet more DHT22 sensor code
Replies: 101
Views: 81007

Re: Yet more DHT22 sensor code

Did you find out what is causing dht22 to stop responding?
by rgrbic
Sat Jun 28, 2014 9:32 am
Forum: Automation, sensing and robotics
Topic: Yet more DHT22 sensor code
Replies: 101
Views: 81007

Re: Yet more DHT22 sensor code

Try to put one more (electrolytic) capacitor between vcc and gnd.
by rgrbic
Sat Jun 28, 2014 7:35 am
Forum: Beginners
Topic: safe to unplug to reboot when RPi lost terminal connection?
Replies: 3
Views: 663

Re: safe to unplug to reboot when RPi lost terminal connecti

Sd card can get corrupted if you just unplug power cord. Therefore I suggest to put shutdown/restart button. But this helps only if you are near RPi so you can press the button.
by rgrbic
Fri Jun 27, 2014 10:33 am
Forum: Automation, sensing and robotics
Topic: Yet more DHT22 sensor code
Replies: 101
Views: 81007

Re: Yet more DHT22 sensor code

joan wrote:
rgrbic wrote:What kind of cable are you using for DHT22 and is this sensor near this appliance?
The DHT22 is plugged into breadboard. The appliance is about 20 feet away on a different ring.
Put a capacitor between dht22 supply pins (Vcc and GND), like 0.1 uF
by rgrbic
Fri Jun 27, 2014 9:56 am
Forum: Automation, sensing and robotics
Topic: Yet more DHT22 sensor code
Replies: 101
Views: 81007

Re: Yet more DHT22 sensor code

What kind of cable are you using for DHT22 and is this sensor near this appliance?
by rgrbic
Fri Jun 27, 2014 9:39 am
Forum: Networking and servers
Topic: My rPi is under attack
Replies: 29
Views: 12838

Re: My rPi is under attack

Here you can find some guidelines how to improve security of your RPi.
Change port number, use key pair based authentication and install fail2ban.
by rgrbic
Wed Jun 25, 2014 10:42 pm
Forum: Other projects
Topic: Fuel flow sensor and open collector signals
Replies: 70
Views: 9463

Re: Fuel flow sensor and open collector signals

These are just clamping diodes to protect gpio input from excessive positive or negative voltage. The pull up resistor is still needed since the output is OC.
by rgrbic
Wed Jun 25, 2014 4:55 pm
Forum: Other projects
Topic: Fuel flow sensor and open collector signals
Replies: 70
Views: 9463

Re: Fuel flow sensor and open collector signals

FLYFISH TECHNOLOGIES wrote:Hi,
rgrbic wrote:Check the posts, nobody said that schmitt trigger can solve the problem.
Ok, sorry. By default, I expect that a content is related to the topic.
My mistake, I should'n mention it at all. Cheers
by rgrbic
Wed Jun 25, 2014 4:34 pm
Forum: Other projects
Topic: Fuel flow sensor and open collector signals
Replies: 70
Views: 9463

Re: Fuel flow sensor and open collector signals

Check the posts, nobody said that schmitt trigger can solve the problem.
by rgrbic
Wed Jun 25, 2014 8:41 am
Forum: Other projects
Topic: Fuel flow sensor and open collector signals
Replies: 70
Views: 9463

Re: Fuel flow sensor and open collector signals

At least he can try with different Vcc and pull-up resistor just to be sure. I suggest to record output to see what kind of signal we are dealing with. You are right regarding Schmitt trigger, it is not crucial in testing phase. Given that the sensor employs a Schmitt trigger on the output is it ne...

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