http://forums.leaflabs.com/topic.php?id=74360 A place to share, learn, and grow... en-US Fri, 22 Jan 2016 00:08:44 +0000 http://bbpress.org/?v=1.0.2 q http://forums.leaflabs.com/search.php http://forums.leaflabs.com/topic.php?id=74360#post-105467 Fri, 18 Jul 2014 17:41:28 +0000 okie 105467@http://forums.leaflabs.com/ <p>To avoid the problems caused by ground loops, which is having induced voltages across and currents through a conductor that is suppose to be equipotential, make good, solid connections between grounds or any conductors that are suppose to be equipotential. A good connection can mean many connections so that there's lower resistance in some situations, while in others, it's better if connections are made in a hierarchical way so that there are little islands of non-interacting peace. If there's fairly low resistance connection between EITHER the GND net or the 3.3V net on the Maple and one of the potentials involved in the the voltage measurement you would like to make, then you probably won't get what you like. For me, the most enlightening resource on ground planes, return currents, impedance lines, high-speed or high-power and/or low-noise PCB layout, and more, was and is a book called Electromagnetic Compatibility Engineering by Henry Ott. </p> http://forums.leaflabs.com/topic.php?id=74360#post-105463 Fri, 18 Jul 2014 02:36:58 +0000 Fullback 105463@http://forums.leaflabs.com/ <p>@ gbulmer: "SerialUSB.println(reading;)" it is a typing error sorry.</p> <p>I do not connect the analog ground, to the ground of the stabilized voltage source, in order to avoid ground loop. But i just tried and it works. THANKS </p> http://forums.leaflabs.com/topic.php?id=74360#post-105462 Thu, 17 Jul 2014 15:30:17 +0000 gbulmer 105462@http://forums.leaflabs.com/ <p>Ah, good point manitou.</p> <p>Fullback:<br /> Have you connected the stabilised power supply to the Ain pin and AV- (analogue ground)?<br /> Could you measure from a battery source (to the analogue pin and analogue ground), to avoid any other ground influence?</p> <p>When you say <em>"even if I use a stabilezed voltage source, the maple board is not able to properly sample it"</em><br /> What values do you get? </p> http://forums.leaflabs.com/topic.php?id=74360#post-105461 Thu, 17 Jul 2014 13:50:04 +0000 manitou 105461@http://forums.leaflabs.com/ <p>common ground? </p> http://forums.leaflabs.com/topic.php?id=74360#post-105460 Thu, 17 Jul 2014 10:46:06 +0000 gbulmer 105460@http://forums.leaflabs.com/ <p>Fullback - is this <em>exactly</em> the code that you are using?</p> <p>If so, it contains a syntax error, and does not compile.</p> <p>This line has the ';' in an incorrect place:<br /> <code>SerialUSB.println(reading;)</code><br /> the ';' should be after the ')'<br /> <code>SerialUSB.println(reading);</code> </p> http://forums.leaflabs.com/topic.php?id=74360#post-105459 Thu, 17 Jul 2014 07:16:12 +0000 Fullback 105459@http://forums.leaflabs.com/ <p>Hello everybody</p> <p>I have got many maple mini rev3 boards as logic units for a wireless sensor network. I have got a problem with the ADC; even if I use a stabilezed voltage source, the maple board is not able to properly sample it. I provide 2.7 V, and i have tried to sample it with different maple mini boards and with all the analog input pin, but I have got different reading for every sampling.</p> <p>The configuration is has follows: a maple mini connected via USB to my laptop ( I have used both a mac and win XP pc ), a stabilezd and constant voltage connected on one of the ain pin of the board.</p> <p>The code is has follows:</p> <pre><code>const int sensorPin =7; int reading; void setup() { pinMode(sensorPin, INPUT_ANALOG); } void loop(){ reading=analogRead(sensorPin); SerialUSB.println(reading;) }</code></pre> <p>I have used this simple code in order to understand whats wrong..</p> <p>additional info:<br /> I have measured the voltage across ground pin and sensor pin, with a kehitley potentiometer (it is a precision instrument) and i have got the right reading.</p> <p> maple IDE v 0.0.12</p> <p>Any suggestions?</p> <p>Thanks </p>