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by repton
Thu Jan 24, 2013 8:20 pm
Forum: Beginners
Topic: How to up a Static IP on Your Wireless Network Connection
Replies: 15
Views: 134595

Re: How to up a Static IP on Your Wireless Network Connecti

I did it a different way. I simply added the following lines to /etc/network/interfaces: auto wlan0 iface wlan0 inet static address 192.168.0.21 netmask 255.255.255.0 gateway 192.168.0.1 wpa-essid not-telling-you wpa-psk not-telling-you-this-either That was it. No raspi-config, no wpa_supplicant.con...
by repton
Thu Jan 17, 2013 9:00 pm
Forum: Automation, sensing and robotics
Topic: DS18b20 usage and setup
Replies: 10
Views: 6681

Re: DS18b20 usage and setup

I have 10 of these sitting waiting for me to get a round tuit. What would you say was a reasonable, stable maximum length for a GPIO-mastered line with good tight twisted pair (not CAT5) and no spurs? I was thinking maybe 10m with 4-6 DS18B20s. I've not actually had enough round tuits myself to tes...
by repton
Thu Jan 17, 2013 8:08 pm
Forum: Automation, sensing and robotics
Topic: DS18b20 usage and setup
Replies: 10
Views: 6681

Re: DS18b20 usage and setup

If they're all over the house then the GPIO based 1-Wire driver isn't going to work for you, it's only any good on relatively short networks. You need some other kind of 1-Wire master. Essentially you have two options, a DS9490R USB to 1-Wire host adapter or some kind of i2c connected master plugged...
by repton
Thu Jan 17, 2013 8:03 pm
Forum: Beginners
Topic: Wifi and Static IP
Replies: 8
Views: 3212

Re: Wifi and Static IP

I have a static IP wifi on one of mine. The entire of the configuration is the following in /etc/network/interfaces, I didn't edit any other files: auto wlan0 iface wlan0 inet static address 192.168.0.21 netmask 255.255.255.0 gateway 192.168.0.1 wpa-essid not-telling wpa-psk not-telling-you-this-eit...
by repton
Wed Jan 16, 2013 10:04 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: 5V power in GPIO
Replies: 23
Views: 5041

Re: 5V power in GPIO

Also the wire for your radio from the plug cannot handle 30A Hang on, a minute ago you were saying the fuse was purely there to protect the upstream circuits, but now you're saying you can't use a 30A fuse in a radio because the cable to the radio can't cope with that. So it seems to me that now yo...
by repton
Wed Jan 16, 2013 8:32 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: 5V power in GPIO
Replies: 23
Views: 5041

Re: 5V power in GPIO

Also the wire for your radio from the plug cannot handle 30A Hang on, a minute ago you were saying the fuse was purely there to protect the upstream circuits, but now you're saying you can't use a 30A fuse in a radio because the cable to the radio can't cope with that. So it seems to me that now yo...
by repton
Wed Jan 16, 2013 4:53 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: 5V power in GPIO
Replies: 23
Views: 5041

Re: 5V power in GPIO

Why is it people get it wrong way round about fuses, the fuse protects the earlier in the supply chain device from faults in the downstream device. Just like mains wiring fuse protects primarily against FIRE, and secondly wiring and infrastructure before the premises. Surely in a mains installation...
by repton
Wed Jan 16, 2013 4:47 am
Forum: Automation, sensing and robotics
Topic: running a program at start up
Replies: 4
Views: 1065

Re: running a program at start up

Either a cron job @reboot as suggested above or stick it in /etc/rc.local is the other common way of doing it.

The advantage of the former is it makes it easy for a non root user to do it, the advantage of the latter is it doesn't rely on cron working.

Paul
by repton
Mon Jan 14, 2013 11:06 am
Forum: Beginners
Topic: Wifi and wpa_supplicant
Replies: 5
Views: 11136

Re: Wifi and wpa_supplicant

Here is my entire /etc/network/interfaces file. I didn't edit any other files to get the WLAN working. auto lo iface lo inet loopback #iface eth0 inet dhcp #allow-hotplug wlan0 #iface wlan0 inet manual #wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf #iface default inet dhcp auto wlan0 iface wlan0 ...
by repton
Thu Jan 10, 2013 9:12 pm
Forum: Beginners
Topic: More I2C ports!
Replies: 7
Views: 2679

Re: More I2C ports!

How would I connect more than one device to each pin? I am pretty sure they have different addresses but I do not know how to connect them to the same pins. I suppose it depends exactly what each device's connections physically look like but essentially you need to run 0V/SCL/SDA from the Pi to one...
by repton
Thu Jan 10, 2013 8:58 pm
Forum: Beginners
Topic: More I2C ports!
Replies: 7
Views: 2679

Re: More I2C ports!

As long as they have different i2c addresses you can connect them both to the same port as the i2c bus will support many devices at once.

Paul
by repton
Thu Jan 10, 2013 8:40 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Reading GPS module via GPIO (uart?) pins
Replies: 9
Views: 24880

Re: Reading GPS module via GPIO (uart?) pins

Be VERY careful when doing this that you don't damage your RasPi. The GPIO UART port runs at 3.3V and is supposedly NOT 5V tolerant, and it sounds like your module is talking to it at 5V.

Maybe a simple 2 resistor voltage divider between the two would work?

Paul
by repton
Thu Jan 10, 2013 8:30 pm
Forum: Automation, sensing and robotics
Topic: Controlling light switch via RPi
Replies: 4
Views: 3536

Re: Controlling light switch via RPi

Why not use another relay connected to the feed to the light that switches the other channel on the DS2413 so you can read back the status of the light?

Paul
by repton
Thu Jan 10, 2013 2:02 pm
Forum: Automation, sensing and robotics
Topic: Reading multiple DS18B20s
Replies: 4
Views: 1029

Re: Reading multiple DS18B20s

The standby current of a DS18B20 is only ~750nA according to the data sheet (which is 0.00075mA, which is near enough zero for all practical purposes) so the number of sensors isn't going to be your issue. The thing that will stop it working is capacitance in the cable if it is too long. I have had ...
by repton
Thu Jan 03, 2013 12:02 pm
Forum: Beginners
Topic: Using the Raspberry Pi without a monitor/keyboard: possible?
Replies: 10
Views: 3905

Re: Using the Raspberry Pi without a monitor/keyboard: possi

I think this is just what I was looking for... Do you use Windows, and if so, what terminal emulator do you use? I'm looking at a tutorial for using this, but the terminal emulator they recommend is ZOC, which costs like $79 (I know there's a free trial, but I want something I can use in the long t...
by repton
Thu Jan 03, 2013 8:41 am
Forum: Beginners
Topic: Using the Raspberry Pi without a monitor/keyboard: possible?
Replies: 10
Views: 3905

Re: Using the Raspberry Pi without a monitor/keyboard: possi

What WiFi adapter is "most compatible", i.e. will have the simplest setup? I'm also looking for one that will work connected straight to the Pi, without a powered hub. I don't know if it's necessarily "most compatible" but I have bought one of these: http://www.ebay.co.uk/itm/370569077102 and found...
by repton
Thu Jan 03, 2013 8:35 am
Forum: Beginners
Topic: Using the Raspberry Pi without a monitor/keyboard: possible?
Replies: 10
Views: 3905

Re: Using the Raspberry Pi without a monitor/keyboard: possi

But, how would the OP configure a WiFi USB dongle from the network before it is configured, or without a Linux PC that could access the ext4 partition on the SD card to configure it? If you want to configure the whole thing completely from scratch without a keyboard and monitor then you need someth...
by repton
Wed Jan 02, 2013 12:43 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: i2cdetect permissions
Replies: 5
Views: 6141

Re: i2cdetect permissions

anyone have any ideas on why i2cdetect fails when running as user pi? Have you logged out and back in again since adding pi to the i2c group? I just tried it myself. To start with I got permission denied. Then I ran "sudo usermod -G i2c pi". It still failed. I logged out and back in again. It worke...
by repton
Wed Jan 02, 2013 12:39 pm
Forum: Automation, sensing and robotics
Topic: DS18B20-PAR 1-Wire Parasite-Power bad value
Replies: 14
Views: 18600

Re: DS18B20-PAR 1-Wire Parasite-Power bad value

In theory it is suitable for direct connection to RPi, how ever RPi provide in ideal condition minimum VPU, which isnt enough for normal operation of temperature sensor. Not with the kernel 1-Wire driver though as (to the best of my knowledge) it doesn't provide the strong pull on on the data pin r...
by repton
Wed Jan 02, 2013 12:33 pm
Forum: Beginners
Topic: Using the Raspberry Pi without a monitor/keyboard: possible?
Replies: 10
Views: 3905

Re: Using the Raspberry Pi without a monitor/keyboard: possi

The simplest way is to get the Pi on your home/office LAN and then you can simply ssh onto it from your PC (assuming your PC is also on the LAN). If there is no easy way to get a wired connection to the Pi, then get a WLAN card for it (assuming you have a wireless LAN in your home/office). Ideally y...
by repton
Tue Jan 01, 2013 12:41 am
Forum: Automation, sensing and robotics
Topic: Reptile vivarium thermostat
Replies: 15
Views: 7419

Re: Reptile vivarium thermostat

It's a shame the DS2438 cannot give me just the values and I could perform the calculation myself. It can, the humidity is not calculated by the DS2438 but is a value calculated in software from three values that are read from the DS2438: VDD, VAD and temperature. I don't know what software you're ...
by repton
Mon Dec 31, 2012 8:29 am
Forum: Automation, sensing and robotics
Topic: Reptile vivarium thermostat
Replies: 15
Views: 7419

Re: Reptile vivarium thermostat

These look like cool bits of kit, however I need the humidity sensor to be really small, like a temp probe etc as it will be inside a vivarium. I was looking for something I can connect to my ds2482-800 like I do my DS18B20 Ahh, these do not (to the best of my knowledge) exist in a 1-Wire form. Tha...
by repton
Sat Dec 29, 2012 1:43 pm
Forum: Automation, sensing and robotics
Topic: Reptile vivarium thermostat
Replies: 15
Views: 7419

Re: Reptile vivarium thermostat

Trying to decide what humidity sensor to use, would like a 1wire one but haven't found one yet. May have to use i2c one. 1-Wire humidity sensors are available, including the SWE3 module I sell. See http://www.sheepwalkelectronics.co.uk/SWE3.shtml for details. Similar modules are also available from...
by repton
Sat Dec 29, 2012 11:04 am
Forum: Automation, sensing and robotics
Topic: Using the old 6-channel 1-wire hub
Replies: 4
Views: 2545

Re: Using the old 6-channel 1-wire hub

Nice site and thanks for taking the time to detail your process but I am slightly concerned about some of the detail in it, for example: Because the Raspberry already uses TTL level signals, we don't need the level shifter anymore. I believe the RasPi uses 3.3V signals for the GPIO UART port and not...
by repton
Fri Dec 28, 2012 8:02 pm
Forum: Automation, sensing and robotics
Topic: DS18B20-PAR 1-Wire Parasite-Power bad value
Replies: 14
Views: 18600

Re: DS18B20-PAR 1-Wire Parasite-Power bad value

I don't think you will get the -PAR sensor to work with the GPIO driver on the RasPi as it doesn't provide the right pull up signal on the 1-Wire data line to power the sensor so it will not work in parasite mode. You either need some "normal" DS18B20 sensors or to use something that does provide po...

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