I have a JN with a pressure plug, that transmits just fine when on the desk a few feet apart. When I move the transmitter horizontally 10 meters is the max at which the receiver, a jeelink, can still receive. This is at 9600 baud as well as at 57600 baud. Vertically it cannot do 3 meters through a wooden floor. I am very disappointed since I have got it all working, but now find out that I cannot place the transmitter were it needs to be. Any suggestions as to how to increase the range? These are RF12 transmitters operating at 915Mz . Thanks for any suggestions.
Transmitter/Receiver Range.
(15 posts) (3 voices)-
Posted 21/05/2010 16:10:46
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Both 10 meters open air and not able to pass through a wooden floor sound like a technical problem. I haven't done range tests yet, but you should be able to get a lot more than that.
Wait a minute ... are you using RFM12B's from the European Jee Labs shop? Those are 868 MHz units. They do work on 433 and 915 MHz, but at severely reduced range, because the on-board RF components are designed for 868.
Posted 21/05/2010 17:28:09 -
No, I bought the RFM12's from Modern Devices here in the States and the JeeNodes from you. Another problem has popped up. Once The units are out of ranch and quit communicating and when I then bring them back next to each other , they never start talking again. The receivers read garbage until I unplug the power from the transmitter and then re-power, and then they start working again. Is that normal also?
Can I send you anything that will help to resolve this? Thanks.
Posted 21/05/2010 19:18:21 -
Strange. Perhaps emailing me some photos could help. And your code, if possible. Bits travel more easily than atoms.
Posted 21/05/2010 20:24:31 -
I had similar problems long time ago, and they were due to the power saving logic...try without any power saving, if you are using any...might help...
Posted 21/05/2010 21:43:58 -
That is an interesting observation. I am using the power saving logic. I have to try without. Jean-Claude, do you want me to post the code on this thread?
Posted 21/05/2010 22:03:50 -
Sure - feel free, just make sure to indent all source with 4 spaces. Otherwise this forum software will mangle it.
Posted 21/05/2010 22:32:50 -
This is the code that I use for the Pressure plug. It works just fine at close range. I wanted to use the power saving features to extend battery life. The commented out Serial Print statements are for debugging purposes and will be deleted once the code has been finalized. There is even code in there that is not doing anything, because I cobbled it together from different sources. I was at one time trying to do a running average, but could not figure it out.
//BMP085
// Ports demo, reads out a BMP085 sensor connected via I2C // 2009-02-17#include "Ports.h" #include "PortsBMP085.h" #include// needed to avoid a linker error :( #include PortI2C two (4); MilliTimer readoutTimer, aliveTimer; word runningAvgPres; byte radioIsOn;BMP085 psensor (two);
void setup() { Serial.begin(9600); Serial.print("\nbmp085demo; rf12config();rf12easyInit(0); // set up easy transmissions at maximum rate // may omit following call if calculate() won't be called later on psensor.getCalibData(); //uint16t praw= psensor.measure(BMP085::PRES); runningAvgPres =psensor.measure(BMP085::PRES); radioIsOn = 1; } static void lowPower (byte mode) { // disable the ADC byte prrSave = PRR, adcsraSave = ADCSRA; ADCSRA &= ~ bit(ADEN); PRR &= ~ bit(PRADC); // go into power down mode setsleepmode(mode); sleepmode(); // re-enable the ADC PRR = prrSave; ADCSRA = adcsraSave; }static void loseSomeTime (word ms) { // only slow down for longer periods of time, as this is a bit inaccurate if (ms > 100) { word ticks = ms / 32 - 1; if (ticks > 127) // careful about not overflowing as a signed byte ticks = 127; rf12sleep(ticks); // use the radio watchdog to bring us back to life lowPower(SLEEPMODEPWRDOWN); // now we'll completely power down rf12sleep(0); // stop the radio watchdog again // adjust the milli ticks, since we've just missed lots of them extern volatile unsigned long timer0millis; timer0millis += 32U ticks; } }void loop() { //Serial.print("\n A; // switch to idle mode while waiting for the next event lowPower(SLEEPMODEIDLE); // keep the easy tranmission mechanism going if (radioIsOn && rf12easyPoll() == 0) { rf12sleep(0); // turn the radio off radioIsOn = 0; } // if we will wait for quite some time, go into total power down mode if (!radioIsOn){ //Serial.print("\n B; loseSomeTime(readoutTimer.remaining()); } //Serial.print("\n AA; // rf12easyPoll(); // keep the easy tranmission mechanism going if (readoutTimer.poll(60000)) { //Serial.print("\n C; //delay(1000); //long tempF; long presHg; //float presHg; uint16t traw = psensor.measure(BMP085::TEMP); uint16t praw = psensor.measure(BMP085::PRES); //Serial.print(praw); // omit following code to avoid linking in some complex calculation code int16t temp; int32t pres; psensor.calculate(temp, pres); // Serial.print (pres); //for testing long tempF=(((temp.9)/5.0)+32.0); //convert Celcius to Fahrenheit long value=(pres0.00029529983071+.565)100; //convert pascals to in of Hg +elevation correction //Serial.println (value); //Serial.print("\n D; //Serial.println(value); char sending = rf12easySend(&value, sizeof value); // force a "sign of life" packet out every 60 seconds if (aliveTimer.poll(600000)){ //Serial.print("\n E; sending = rf12easySend(0, 0); // always returns 1 } if (sending) { // make sure the radio is on again //Serial.print("\n F; if (!radioIsOn) rf12sleep(-1); // turn the radio back on radioIsOn = 1; } //Serial.print("\n G; } //Serial.print("\n H; }Posted 22/05/2010 00:20:20 -
Having removed the power saving code, I notice way fewer false transmission. I am only getting a couple of ? packages since removing the code a few hours ago. i will do the range test tomorrow.
Posted 22/05/2010 03:21:05 -
Okay, I loaded the sketch that does not have the power saving code and now the range has at least doubled and I can now place the transmitter where it needs to be. Jean-Claude could you look into why the power saving code seems to reduce the range? I also read somewhere that the RFM12 has a battery monitoring function. Is there a way to access that?
Posted 22/05/2010 16:16:34 -
Yeah, I've been meaning to revisit the battery saving stuff for some time now. It's still not quite good enough - my room nodes tend to run out of juice within about month. Probably the retry-when-no-central-node-is-present problem. Maybe there's more to it.
Can't say when I'll get to it. There's a lot of stuff keeping me busy, right now...
I'm at a loss to explain how this affects range, though.
Posted 22/05/2010 16:32:52 -
Thanks amvv the power saving code seems to have been the problem. Eliminating the code increased the range by at least a factor of two. The 9 volt battery died inside of 3 hours after removing the code. Jean-Claude it would be nice if you could get the power saving to work without decreasing the range.
Posted 23/05/2010 01:19:35 -
Right now I am reading one pressure plug on port 4 on the JN. What would I have to do to the sketch in order to read another pressure plug on port 3 for example?
Posted 23/05/2010 16:29:54 -
Somewhere in the wiki I have placed the code for a weather station I built using the JeeNodes. I wrote then a different power saving, that does not use the RF12 watchdog. The JeeNode has been running now for 5 months, on 3 AA cells (alkaline), sending packets every 10 minutes. I do not have any acknowledge system, it is fire and forget :) It has sent about 24000 packets, and although sometimes a few are lost, it somehow continues later on, but from the counter I know that the JeeNode kept working, so something probably disrupts the communication - This does not happen very often, so it is pretty reliable. I also think that to improve the chances I transmit every packet 3 times (that might not be in the wiki), so the JeeNode has in fact send close to 70000 packets!!
Posted 24/05/2010 18:40:26 -
Your code is in the "Loose Ends" area of the café for now - see
Posted 24/05/2010 18:49:31