tag:blogger.com,1999:blog-4359208343555922820.post5746233057423672387..comments2024-01-12T06:26:30.504+00:00Comments on Random Tech Stuff: Arduino to Android IO on the cheap (aka Poor Man's NFC)JoeDhttp://www.blogger.com/profile/02413638198679968289noreply@blogger.comBlogger31125tag:blogger.com,1999:blog-4359208343555922820.post-66218682388872931112016-10-23T06:07:19.642+01:002016-10-23T06:07:19.642+01:00Love this project, but what a difference just a fe...Love this project, but what a difference just a few years makes eh? Who would have thought in 2016 we'd have programmable HC-05's and ESP8266's etc shipping from China for a buck a piece, postage included?<br />MarkFhttps://www.blogger.com/profile/00703089781952022209noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-51426096291447557332014-08-22T14:31:21.751+01:002014-08-22T14:31:21.751+01:00Roger, Looks like a cool project. Best of luck wit...Roger, Looks like a cool project. Best of luck with your competition entry (that the competition where the grand prize is a sub-orbital space flight, right?). Joe.Joe Desbonnethttps://www.blogger.com/profile/01861293299381288570noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-62688855907432800892014-08-22T10:46:46.577+01:002014-08-22T10:46:46.577+01:00Hi Joe,
I've entered "The Hackaday Prize...Hi Joe,<br /><br />I've entered "The Hackaday Prize" with a system of text communication for the severely disabled. I'm using electromagnetic coupling to a smartphone's geomagnetic sensor as the interface to a switch. Although this was original to me, I soon researched the idea and of course came to your excellent blog.<br /><br />You're mentioned, and your blog and video are linked from this page on my blog -<br /><br />http://aacswan.blogspot.co.uk/2014/08/first-experimentation-using-app.html<br /><br />I just thought I'd inform you that I'd acknowledged your "prior art"<br /><br />My entry for The Hackaday Prize, SWAN open source AAC, can be found here -<br /><br />http://hackaday.io/project/2626-SWAN-open-source-AAC<br /><br />Best regards,<br />Roger CurryUnknownhttps://www.blogger.com/profile/15517185067938664102noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-32965053990396919582012-10-11T04:44:58.505+01:002012-10-11T04:44:58.505+01:00The reason it is a one way communication is becaus...The reason it is a one way communication is because magnatometer of phone is a passive device ( detects magnetic field) and arduino here works as an active device (provides power). The magnatometer provides power but not as much as to become an active device. <br />For dual communication NFC (Near Field Communication) is what is coming in phones. Its very similar to what u r doing here. Look into it if u r interested.Rishabhhttps://www.blogger.com/profile/09858431129247284893noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-86091172084254969232012-08-18T16:05:22.847+01:002012-08-18T16:05:22.847+01:00Seems like a much higher data rate could be achiev...Seems like a much higher data rate could be achieved by connecting a peizo speaker to the Arduino and using the microphone on the Android. Basically use FSK (2 different tones) for 0 and 1. This is the way early computer modems worked.Mike Whitentonhttps://www.blogger.com/profile/03248999440249359232noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-17568836515140661642012-07-16T21:32:48.178+01:002012-07-16T21:32:48.178+01:00I suspect anything audible would be beyond the fre...I suspect anything audible would be beyond the frequency response of the magnetometer. But you might see some response at frequencies below 10Hz. Only way to find out is to try :-)Joe Desbonnethttps://www.blogger.com/profile/01861293299381288570noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-6014969666571195962012-07-16T18:16:29.119+01:002012-07-16T18:16:29.119+01:00Sorry to dig an old post.
I was asking myself a q...Sorry to dig an old post.<br /><br />I was asking myself a question : is it possible to replace the coil by a speaker ? The idea : instead of using Arduino + a coil, we would use a smartphone or a desktop, playing a pre-defined square wave audio sample, moving the speaker (and it's magner at the same time). Do you think that the magnetometer can catch that magnetic pulse ?Anonymoushttps://www.blogger.com/profile/04274985400485796581noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-76089157302982692252012-06-15T23:06:18.761+01:002012-06-15T23:06:18.761+01:00THIS is a hack !THIS is a hack !Goebishhttps://www.blogger.com/profile/07714364127959917753noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-61281133933547869692012-04-30T09:26:38.870+01:002012-04-30T09:26:38.870+01:00Excellent tutorial, I am able to generate the same...Excellent tutorial, I am able to generate the same result on the first try. :) <br /><br />I have a question and hope you can help. If I need to create a magnetic field to turn on a reed switch, do I a coil with longer diameter or more turns? <br /><br />ElEltonhttps://www.blogger.com/profile/06379180428676559505noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-4705632567711180392012-03-05T19:55:04.400+00:002012-03-05T19:55:04.400+00:00Hi, great project. Would a larger antenna increase...Hi, great project. Would a larger antenna increase the communication range?pgfhttps://www.blogger.com/profile/14855901290817370910noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-31990349697443077052012-02-27T08:18:53.139+00:002012-02-27T08:18:53.139+00:00Yes, it might be. Maybe then I will implement some...Yes, it might be. Maybe then I will implement some optic poor man communication :)Stefanohttps://www.blogger.com/profile/14786876851113224201noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-3940038102002816702012-02-26T18:50:11.147+00:002012-02-26T18:50:11.147+00:00stefano, It's quite possible the sensor in the...stefano, It's quite possible the sensor in the Galaxy Nexus has a slower response. Unfortunately I cannot find out what sensor the Galaxy Nexus uses for the compass/magnetometer.<br /><br />I've actually got that phone so I'll check it out when I get a chance.Joe Desbonnethttps://www.blogger.com/profile/01861293299381288570noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-38986464702180803862012-02-26T17:14:11.280+00:002012-02-26T17:14:11.280+00:00nice hack!
I am trying to implement it, using ardu...nice hack!<br />I am trying to implement it, using arduino uno and a samsung galaxy S. I am using resistor and flyback diod as you described, but (from tricorder), it seems that when I use a square wave with period less then 800 ms, the sensor does not get it. Plus, the wave seen by tricorder is a sinusoid, and not a square one. Do you think it might be the sensor of the phone? I am a total beginner, this is the first resistor that I touch.Stefanohttps://www.blogger.com/profile/14786876851113224201noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-23965080028357955682011-11-27T14:20:34.351+00:002011-11-27T14:20:34.351+00:00C. Brito: Take a look at the Android source code l...C. Brito: Take a look at the Android source code linked near the end of the article:<br /><br />http://code.google.com/p/wombat-blog/downloads/detail?name=WombatPMNFC-0.1.tar.gz<br /><br />You will need to setup the Android development environment to compile it. See http://developer.android.com/Joe Desbonnethttps://www.blogger.com/profile/01861293299381288570noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-90989883372737729482011-11-26T23:23:16.020+00:002011-11-26T23:23:16.020+00:00Hi
I am a student of Electrical and Computer Engin...Hi<br />I am a student of Electrical and Computer Engineering in Portugal.<br />I'm doing a work like this but I will do only the receive code in android.<br />Can you explain me how you do the receiver code? <br />thank you for your attention. <br /><br />C. BritoSofiahttps://www.blogger.com/profile/03771641223311707258noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-26421072697552566442011-10-14T07:29:30.792+01:002011-10-14T07:29:30.792+01:00This comment has been removed by a blog administrator.Anonymoushttps://www.blogger.com/profile/12566620925607112209noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-84332500883349479172011-08-18T16:32:18.741+01:002011-08-18T16:32:18.741+01:00The app "Sensor List" from publisher &qu...The app "Sensor List" from publisher "Idea Matters" (available free on the Android Market) gives a list of the sensor devices used. I think that's how I got the sensor chip number.Joe Desbonnethttps://www.blogger.com/profile/01861293299381288570noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-60550162746526792332011-08-18T15:37:01.699+01:002011-08-18T15:37:01.699+01:00I came here looking for which magnetometer the HTC...I came here looking for which magnetometer the HTC Desire uses. Thanks for mentioning it.<br /><br />How did you find it out? I want to know the magnetometer used by the Samsung Galaxy 3.<br /><br />PS. Very interesting blog. I love such DIY hacks.HRJhttps://www.blogger.com/profile/07182524959403566214noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-36493134802175087572011-07-15T13:19:50.658+01:002011-07-15T13:19:50.658+01:00The 'ÿ' character is 0xFF... all binary 1....The 'ÿ' character is 0xFF... all binary 1. It's not picking up a good signal.<br /><br />Two suggestions: 1. Looking at the output from the Tricorder app... I'm wondering is that a strong signal. I don't think so. Are you sure you have the location of the magnetometer correct? What make/model of phone is it?<br /><br />2. Something I should have mentioned in the text. I've got a hard coded threshold value. See constant 'THRESHOLD' in the code. You'll need to set that about half way between the on and off values.<br /><br />My email address is jdesbonnet at gmail dot com if you want to follow up.Joe Desbonnethttps://www.blogger.com/profile/01861293299381288570noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-66578076249433331102011-07-15T12:09:46.131+01:002011-07-15T12:09:46.131+01:00it's so fine. i found my way to finish all the...it's so fine. i found my way to finish all the steps you wrote. <br /><br />but i think there is a bug in android source code if use in another android device, i am using motorola defy.<br /><br />it appears the charracter of word "Y" double dotted above it. even when the coil is not near the magnetometer, this is my video of it --> http://www.youtube.com/watch?v=kG7zlInyBR8<br /><br />i think the code for android need to be specified for each device. thanksryanzehttps://www.blogger.com/profile/06111788032276745379noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-48193210464718553962011-07-14T21:58:58.133+01:002011-07-14T21:58:58.133+01:00You are indeed correct. The resistor and diode are...You are indeed correct. The resistor and diode are not present in the video. <br /><br />The resistor is a current limiting resistor to prevent too much current being drawn from the Arduino IO pin. I had originally miss-read the Arduino documentation and thought that there was a resistor already in series for IO pin 13. So I never bothered to use an external resistor. I later discovered that was incorrect. But as there was no harm done and I had been using it for hours that way I decided to make the video without putting in the extra resistor.<br /><br />The diode is a 'flyback' diode which protects against a voltage spike when the coil is suddenly driven low. They are important when driving large coils (eg relays). But for such a small coil it's not necessary. It's included in the schematic for completeness. <br /><br />Re the Android code. I just packed up the code from my Eclipse project. I didn't think too hard about the best way of packaging it -- sorry if it doesn't work out-of-the-box. If I get a chance later I'll write a short howto on getting that setup.Joe Desbonnethttps://www.blogger.com/profile/01861293299381288570noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-67746078102324446172011-07-12T01:04:09.300+01:002011-07-12T01:04:09.300+01:00it works great!
but as i see in yout electronic s...it works great!<br /><br />but as i see in yout electronic scheme, you put a resistor and a diode, but not with your video. whats with that?<br /><br />and also one more question.<br />how to compile the software in android to get the "Hello World" work? i'm sorry i'm really new in stuff like this, all i used to see is .apk not linux's .tar.gz<br /><br />regards.ryanzehttps://www.blogger.com/profile/06111788032276745379noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-45169938051280758772011-07-12T00:54:17.944+01:002011-07-12T00:54:17.944+01:00This comment has been removed by the author.ryanzehttps://www.blogger.com/profile/06111788032276745379noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-85779288302506563232011-07-11T20:37:40.119+01:002011-07-11T20:37:40.119+01:00It sounds like the coil is not making electrical c...It sounds like the coil is not making electrical contact. Magnet wire is covered by a layer of clear insulation (that's why you can coil it without causing a short). Make sure you scrape this insulation off the last 1cm or so of both ends of the coil using a knife before stuffing it into the Aurdino header sockets.<br /><br />As the diameter of the magnet wire is likely to be much smaller than the socket holes you may need to do something to get a good electrical contact. Two ideas are:<br /><br />1. Stuff a small segment of bell wire along with the magnet wire into the Arduino socket. If you look closely at the photo in my post you can see that's what I did.<br /><br />2. To both ends of the coil solder a segment of bell wire which will fit snugly into the socket. Or if you have a suitable male header solder the coil to that.Joe Desbonnethttps://www.blogger.com/profile/01861293299381288570noreply@blogger.comtag:blogger.com,1999:blog-4359208343555922820.post-64123803521392921782011-07-11T18:01:20.015+01:002011-07-11T18:01:20.015+01:00hello, i am really interested in this hack.
but i...hello, i am really interested in this hack.<br /><br />but i can't go forward after the first sketch, the led keeps blink even after i connected the coil to arduino. anything wrong?ryanzehttps://www.blogger.com/profile/06111788032276745379noreply@blogger.com