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armorer posted:
Some dude on the forums is making a twitter-enabled bong
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Feb 23, 2013 05:06
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| # ? May 15, 2024 10:28 |
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ante posted:Some dude on the forums is making a twitter-enabled bong He finished it.
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Feb 23, 2013 05:07
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So it turns out I *didn't* have a USB micro cable on hand. I have a bunch of what turn out to be non-standard cables that are similar to micro-B. Not all is lost, however. For the first time in history a Blackberry Storm actually did something useful! A few weeks back while cleaning out the guest room I found my fiancé's old BB charger. Micro-B connector, 700mA! Just what the r.pi needs. I got Raspbian loaded onto an SD card, HDMI cable hooked up and it booted like a champ. I did run into an issue with my older Apple USB Keyboard; when I pressed keys sometimes they seemed to soft-stick or enter random garbage. Turns out that's the symptoms of not enough power, but it was enough to get SSH turned on. (If anyone is interested, fully powered the r.pi will put out max 140mA to each USB port.) I've got a real, high quality USB cable coming on Monday. After reading a really good breakdown of various high quality USB chargers I've decided to power it from one of the many iPad chargers I've got sitting around. (They did show some voltage sagging [4.6V@2.3A] when pushed to the limit, but the r.pi won't draw more than 1.5A, so it should be perfect for the job.) I also picked up a small powered hub to plug more things into. I think one of the first projects I'm going to tackle is to design (and have printed) a case that will house the r.pi and some LiPo cells. I'm thinking four of these would work very nicely, providing 7.4v@11.6Ah (or 3.7V@23.4Ah, depending on the power circuit I build). I think that'll keep it running for several hours! I'd like to build the power control circuit and have it fully interface with the r.pi over GPIO, so it can take advantage of APM features, report battery life, perform safe shutdowns, that sort of thing.
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Feb 23, 2013 05:47
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Does anybody know of a good way to detect water levels in a smallish reservoir? I would like for it to be small, safe to put in consumable water, and discreet so that inquiring noses don't mistake it for food and eat it. I tried two exposed tips of copper wire in the water, but they didn't conduct.
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Feb 23, 2013 09:18
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NecroBob posted:Does anybody know of a good way to detect water levels in a smallish reservoir? I would like for it to be small, safe to put in consumable water, and discreet so that inquiring noses don't mistake it for food and eat it. https://www.sparkfun.com/products/10221 edit: There does not seem to be information about whether this is food safe. sleepy gary fucked around with this message at 10:03 on Feb 23, 2013 |
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Feb 23, 2013 10:01
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NecroBob posted:Does anybody know of a good way to detect water levels in a smallish reservoir? I would like for it to be small, safe to put in consumable water, and discreet so that inquiring noses don't mistake it for food and eat it. You'll probably need an adc (analog to digital converter) that takes the weak current between the electrodes and turns it into a serial signal the pi can understand. A digital pin needs a certain amount of current and voltage to register high, more than a weak conductor like water could deliver. Come to think of it, you might be able to use a transistor to boost the current coming from the electrodes to see if the water is touching. I think it's npn you would want. Try that first. It's cheaper/simpler, and you can find the parts at a radio shack. Maybe two transistors could do it if one doesn't work... Try this if you want a more polished solution. You'll need an adc, though. Edit: Or, just put the vessel on a weight/pressure sensor and tare out the weight of the container. Divide the water's weight by whatever unit you prefer (water volume is dead simple to derive by weight in either metric or Imperial). Plus, nothing actually touches the water. A Wii Fit balance board is about $30 on ebay, probably free on Craigslist or Freecycle if you're lucky, and a bluetooth USB dongle is about $5-10. Here's a guy who made them talk on Linux: http://www.mattcutts.com/blog/linux-wii-balanceboard/ I've not seen anyone get the balance board working with the Pi, but I do see other people have the other Wii controllers working, so I don't see that being much of an issue. Plus, no wiring! If you just want the pi to tweet/play an alarm when you need to refill a container outside, you could keep the pi safely inside. I'd probably weatherize the balance board a bit, though. Maybe put it in two or three of those big 10 gallon "storage" zip lock bags. TVarmy fucked around with this message at 14:45 on Feb 23, 2013 |
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Feb 23, 2013 14:19
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DNova: Unfortunately, the datasheet said that it needs to be kept vertical and not bent, which is incompatible with the vessel I have in mind. TVarmy: My test was a simple circuit, two AA batteries, an LED, and two open copper ends. Would a transistor be able to amplify even a really weak connection like that?
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Feb 23, 2013 17:17
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NecroBob posted:DNova: Unfortunately, the datasheet said that it needs to be kept vertical and not bent, which is incompatible with the vessel I have in mind.
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Feb 23, 2013 18:01
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underlig posted:If it didn't lead current, why not do something as similarly "simple", two copper wires, one attached to something that floats (styrofoam?), floats up towards the second wire. Or do you need it to detect a low level of liquid? Like a food-grade toilet mechanism.
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Feb 23, 2013 18:04
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underlig posted:If it didn't lead current, why not do something as similarly "simple", two copper wires, one attached to something that floats (styrofoam?), floats up towards the second wire. Or do you need it to detect a low level of liquid? Yeah, I would like to detect a low level of liquid. Obvious physical devices in the water would not last long at all, unfortunately.
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Feb 23, 2013 18:40
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NecroBob posted:DNova: Unfortunately, the datasheet said that it needs to be kept vertical and not bent, which is incompatible with the vessel I have in mind. I think you would able to put it at any orientation you want, but the readout would have to be calibrated to your vessel. You could write a pretty simple python script to do the conversion.
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Feb 23, 2013 18:46
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NecroBob posted:Yeah, I would like to detect a low level of liquid. Obvious physical devices in the water would not last long at all, unfortunately. Ok, what have you got in there. Sharks? Piranhas? Angry turtles? Genetically modified goldfish? You're being very koi about all this
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Feb 23, 2013 19:17
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baka kaba posted:Ok, what have you got in there. Sharks? Piranhas? Angry turtles? Genetically modified goldfish? You're being very koi about all this Zing! I suppose I have been, my apologies. I'm thinking about making a water bowl for my dog that will let me know when I need to refill it. I know I could just look, but I think it would be a fun project to try. She's a chewer, so I need to make it as inconspicuous as possible, otherwise she will likely eat it and that would be a Bad Thing.
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Feb 23, 2013 20:02
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What I’d do is get two pairs of copper strips and attach them down the side of the bowl. Hook that up to a simple A/D converter and just read that data over the GPIO. (I know I’ve seen adhesive metallic strips on various sites. You can get a simple Pi Plate with an A/D converter on it for cheap on eBay.) There’s a good example for you. Alternatively, you could just use one set of copper pads and measure the resistance, it should get higher as the water level gets lower. Edit: http://www.amazon.com/JVCC-CFL-5CA-Copper-Conductive-Adhesive/dp/B000UZ8SJK/ HATE TROLL TIM fucked around with this message at 21:23 on Feb 23, 2013 |
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Feb 23, 2013 20:39
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Some sort of pressure sensor under the base to send an alert based on weight?
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Feb 23, 2013 21:29
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Yeah i think you are looking at it wrong. I for that application I would say weight is the easiest, with a moisture sensor at the top of the bowl being second. The weigh method has the added advantage of you watching loss over time to consumption and evaporation, and knowing exact amount to fill up Although the real easiest method would be a bowl fed by an upside down two liter bottle where the water level of a full bowl self regulates. But i like the tinkering
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Feb 23, 2013 22:26
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What about a ultrasonic range sensor mounted on the ceiling? Or use the upside down bottle, but put the float sensor in the bottle.
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Feb 23, 2013 22:58
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Guy Axlerod posted:Or use the upside down bottle, but put the float sensor in the bottle. Floating conductive ball in the bottle. Two contacts in the neck of the bottle that are bridged when the ball is at the bottom.
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Feb 23, 2013 23:08
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Instead of putting the sensor in the dog bowl, put it in one of these automatic waterer things http://www.amazon.com/Replendish-Wa...tic+Dog+Waterer
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Feb 23, 2013 23:45
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Train the dog to fill his own drat water.
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Feb 23, 2013 23:47
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Found a great deal on a Motorola Droid Bionic Lapdock! I’m going to hardwire a short, full sized USB and HDMI cable into for now until I can design a new “dock” module for it that has female ports. I’m also going to retrofit it with larger LiPo batteries. I picked it up for under $50, so I’m really pleased. This will make the perfect workstation for working with the Pi; HDMI display, full sized keyboard, mouse, two USB ports and battery A/C power! It looks like you only need one USB cable on the newer Revision 2 Pis, since power can back feed over the regular USB ports because it’s not fused. Ideally I’ll have a new cover 3D printed that flush fits to close the back up where the dock is now, just have a full sized HDMI and USB port there; keep a retractable USB and HDMI cable plugged in I’ll be good to go!
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Feb 24, 2013 03:27
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Looks like there's now a multiboot manager/installer for the pi, looks really useful! http://www.berryterminal.com/doku.php/berryboot
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Feb 24, 2013 15:31
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Yeah, Berryboot is pretty neat. I’m building a FreeBSD image right now for the Pi. Once I’ve got it up and running I’ll upload it as a normal image and one that’s Berryboot compatible if anyone wants to play with it.
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Feb 24, 2013 22:19
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I thought the Pi was a joke initially when I bought one but now I'm on my third after giving one to my father to just act as a wireless printer server and now I have one in a weatherproof box with a solar powered case to act as an always on camera on the top of my building for weatherunderground purposes and now I have another for XBMC. I also used it the other day to act as an airprint server at an internet cafe when I needed to print something from my iPad over Airprint. These drat things come in handy. Also it's worth getting a script I can't think the name of currently that will email you the Pi's ip when it comes online so you know where to ssh into easily.
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Feb 25, 2013 04:43
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got dat wmd posted:Also it's worth getting a script I can't think the name of currently that will email you the Pi's ip when it comes online so you know where to ssh into easily. Personally I think that using Avahi to register the Pi in Bonjour as raspberrypi.local or something similar is a superior method, especially if you have a Mac (but you can use Avahi on Linux or Apple's Bonjour implementation for Windows, so this isn't Mac-exclusive). This blog post instructs you on how to install and configure Avahi so that you can SSH to the RPi regardless of its IP.
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Feb 25, 2013 05:24
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Are there any low-effort methods right now to hook up a capacitive touchscreen to get an almost-tablet form factor? I could probably design something like that from scratch, but that'd be a project all to itself.
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Feb 25, 2013 08:10
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Most of the challenge is going to be finding a touchscreen with enough resolution to be worthwhile without breaking the bank. All I want is a LCD display that can do 80x25 text...
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Feb 25, 2013 09:09
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chutwig posted:Personally I think that using Avahi to register the Pi in Bonjour as raspberrypi.local or something similar is a superior method, especially if you have a Mac (but you can use Avahi on Linux or Apple's Bonjour implementation for Windows, so this isn't Mac-exclusive). This blog post instructs you on how to install and configure Avahi so that you can SSH to the RPi regardless of its IP. Yeah, that's what I did anyway for my Airprint installation but if you're using a Pi in many places, it's more useful to have the ip available immediately. I just wish there was a way to be able to headless tell it a wifi username/password sometimes, but I guess that's impossible.
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Feb 25, 2013 16:33
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got dat wmd posted:I just wish there was a way to be able to headless tell it a wifi username/password sometimes, but I guess that's impossible. You could maybe have it parse a text file on a USB stick which you edit on another computer, but that'd be annoying.
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Feb 25, 2013 16:48
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got dat wmd posted:Yeah, that's what I did anyway for my Airprint installation but if you're using a Pi in many places, it's more useful to have the ip available immediately. You could use a FTDI cable hooked up to the serial port to reach the console, although that's not much more convenient than just hooking it up to a keyboard and screen.
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Feb 25, 2013 19:29
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Why not just connect the Ethernet to your laptop?
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Feb 25, 2013 19:40
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I got FreeBSD built from -CURRENT sources and booting on the rpi. I’m working on getting X11 running. It looks like it’s detecting the GPIO, but I don’t have any way to try it out right now. (I have a breadboard and some other supplies coming.) I’m going to start fixing bugs and submitting patches to help get this into a real release. I’m setting up my server to do nightly builds and I’ll post information for that once it’s running, but in the mean time here’s a working build! Download: FreeBSD-HEAD ARMv6 (10.0 R247277) SHA256: 3d9df2a8d5c15b2ecdd5762cf48ad04783e31a23d23672b10c63d5c23725ee89  Default Login/Password: pi/raspberry code:
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Feb 26, 2013 02:14
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This is impressive. Thanks for posting the build.
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Feb 26, 2013 03:38
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Oh, there’s also an unofficial pkg repository that’s been setup since building from ports on the rpi would be painfully slow. You’ll need to bootstrap it with pkg-static.code:http://kernelnomicon.org/?p=261 HATE TROLL TIM fucked around with this message at 04:35 on Feb 26, 2013 |
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Feb 26, 2013 04:31
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My Lapdock came in today and I’ve got to say, this thing is really well built. Now the long wait for the adapters to come in from China…  This thing is really going to be useful though, I can already tell. Dedicated display, keyboard, mouse, USB hub *and* it powers the RPi through the upstream USB port? It’s like this thing was made to use with an RPi.
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Feb 27, 2013 23:27
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This is kind of a noobish question, but I'm noticing my Raspberry Pi slowly fills up its memory as it runs over the course of several days, according to free -h. I don't know how Linux allocates/deallocates memory. Is the used memory not all being actively used and some of it having the potential to be recycled if need be? Or is something leaking memory and I need to fix that? Over the course of staying on for ~two-three weeks, it started running low on ram (~410 used of ~430MB) and responding slowly over SSH. If the two issues are related, is there any way I could start working on diagnosing this? EDIT: I was running screen, IRSSI, and an Apache webserver to host a GPIO controlling web app I made.
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Feb 27, 2013 23:32
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TVarmy posted:This is kind of a noobish question, but I'm noticing my Raspberry Pi slowly fills up its memory as it runs over the course of several days, according to free -h. Post your output when you run free. The first line of free includes memory used by the disk cache and buffers into the "used" number. If you really are running out of memory then post the output of this as well "ps aux | sort -n -k 6 -r | head".
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Feb 27, 2013 23:39
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Where's the best place to buy these from in Canada? It seems all the retailers on the official site ship from the US and it'd be lame to get nailed on Customs fees.
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Feb 28, 2013 07:22
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Where in Canada?
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Feb 28, 2013 07:31
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| # ? May 15, 2024 10:28 |
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ante posted:Where in Canada? Vancouver
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Feb 28, 2013 08:33
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