Battery Sensor v 1.0 PCB


  • Hero Member

    Previously I reported that I was working on developing a PCB for battery operated sensors to meet the following criteria:

    • Powered by CR123 3v Lithium Battery
    • 0.8v > 3.3v converter/regulator for max battery life
    • Support for 2@ Digital, 2@ Analog, 1@ L2C interface
    • Screw terminal blocks for sensor attachment

    The v1.0 PCB came back from OSHPark yesterday and I've installed all the parts and loaded a known working Temp/Humidity/Light sketch with the addition of the battery level reporting as described on My Sensors.

    I'm pleased to report that it installed and operated the first time and my VeraLite located and included it without a problem. I do have a problem with the battery voltage information and suspect I swapped the 1M Ohm and 470K Ohm resistors the voltage divider.

    It's a very spacious board ... for my first attempt at Eagle and PCB design and creation I chose not to try to conserve real estate but rather give myself plenty of room to work. I also have a minor component placement problem with the space allocated for the voltage divider resistors.

    I'm considering a version 2.0 board to correct the few errors and to include some other functions to make the board more general purpose battery or external power:

    • 2.1mm barrel connector and 7805 regulator for external power
    • 1v > 5v converter to allow 5v sensors on the battery version
    • 5 pin screw terminal blocks to support both 3.3 and 5 v sensors on any version

    I will make the current v 1.0 version available on OSHPark if anyone is interested.

    I have attached some photos of the board, components and the assembly. Everything is in sockets for this test but in production I'd probably solder the subassemblies directly to the board20140711_101852.jpg 20140711_101639.jpg 20140711_101629.jpg 20140711_101603.jpg 20140711_101515.jpg 20140711_101501.jpg 20140711_101449.jpg 20140711_101424.jpg 20140711_101407.jpg 20140711_114308.jpgScreenHunter_127 Jul. 11 12.39.jpg


  • Mod

    @clippermiami Ah, there are the images πŸ˜‰
    Very nice and spacious indeed!
    Why did you decice to bring the 3V from the bttery to 3.3V? Do you need a stable supply for sensors?


  • Hero Member

    @Yveaux Well, it just seemed to make sense. The CR123 is a 3V battery and the Arduino is 3.3V for a starter. And the upconverter/regulator allows 3.3v out from a battery input as low as 0.8v so I thought that would help extract as much juice a possible from the battery.

    John


  • Mod

    @clippermiami There's another discussion going on here about regulating to 3v3 from batteries. The Arduino & RF24 will still run fine if voltage drops, and it saves you the loss of the regulator.
    Anyway, just start it up and see how long the battery will last!


  • Mod

    @clippermiami nice work!
    which IC is used for step-up?


  • Hero Member


  • Hero Member

    If anyone is interested the board is shared on OSHPark under my UserName "ClipperMiami" as

    "https://oshpark.com/shared_projects/PtJRVGUP"



  • Nice work!!! I would avoid the step-up module... for a low discharge scenario CR123 give us almost all juice with their voltage up to 1.9V (nRF24L01 limit).


  • Hero Member

    @BSoft Interesting point. That would simplify things a bit πŸ™‚


  • Mod

    @clippermiami said:

    @BSoft Interesting point. That would simplify things a bit πŸ™‚

    Exactly my point πŸ˜‰

    And as a bonus it would probably run longer on a single battery!



  • You will have to disable BOD fuses if you want to work below 2.4V.

    Please also take in account that using atmega328p below 2.4V will decrease operational frequency (below 8MHz).

    More details at this post: link text

    I still prefer to avoid any type of regulators.



  • With a 4 MHz crystal it can run to near 1V8. See page 310 of the data sheet.

    The radio could run directly off the battery and the CPU and sensors off the inverter. That may be a good compromise as the radio draws the most amount of power?


  • Mod

    @a-lurker

    @a-lurker said:

    With a 4 MHz crystal it can run to near 1V8. See page 310 of the data sheet.

    crystal also need some power to operate
    running without crystal can help
    with mysensors battery board we decided to not use crystal
    MCU will run from internal RC 8MHz with CLDIV8 enabled
    etc. basic frequency 1MHz with ability to speed up to 8MHz on the fly

    The radio could run directly off the battery and the CPU and sensors off the inverter. That may be a good compromise as the radio draws the most amount of power?

    radio draws about 12mA at time of receive/transmit
    but while you thinking about battery life it is important to think not about current draw, but about power consumed
    the power is a function of current multiplied by time

    in this logic for example DS18B20 is very power consuming, because it needs a few mA for 750ms
    radio consumed 12mA but for shorter time
    MCU consumes less but for much longer time, and you need to understand it's average current consumption through the circle between sleep and active modes



  • @axillent I'm in agreement.


  • Hero Member

    I've found what may be the first problem with this unit. I have a combination temp/humidity/light sensor running on it, a known good sketch that works on other hardware. I added battery measurement support to it and it appears to work fine.

    This morning I noticed it had not updated Vera since 11:20 last night. This is the second time I've seen this so far but each time I start working on debugging it seems to start working. The common element is that it was sitting on a window sill in the kitchen so I could get easy access to measure the battery voltage and when I debug its on a counter in the family room. The difference is the kitchen is about 15 feet further away from the gateway! The path is no more obstructed in either room, there is essentially one wall between the gateway and the sensor remote.

    I have a scramble-wired 5v version running for test and it reports everywhere in the house. The PCB version fails in the bedroom, again about 20 feet further from the gateway than the family room. I've changed radios so it doesn't appear to be just a weak radio.

    I have a good solid 3.3V on the radio Vcc so it isn't a voltage drop problem. I'm wondering if there is a problem with the radio sitting over the PCB ground plane. I have one of the Seeed Studio DevDuino v 2.0 units an the radio also sits over the ground plane on that device. I haven't gotten around to programming it yet so I can't compare the performance.

    I'm also trying a radio with the external SMA antenna and found that, as one might expect, it works at considerable distance, in this case over 100 feet down the street, through the concrete block external house walls.

    I removed the radio from the PCB socket and put it on a cable about 8 inches long to get away from the ground plane and that does NOT appear to have made any difference. However, if I hold the unit up over my head at arms length the gateway does get the update.

    Can anyone comment on your experience with the basic NRF24L01 radio modules in terms of range from the gateway, obstructions in the path, etc. Any opinion on the likelihood of a ground plane problem?

    Also FYI, I've been monitoring the battery voltage externally and in the past 36 hours the battery voltage has dropped 0.04v. This is without making any changes to reduce drain such as cutting the LEDs, using the Low Power Library, etc. I expect that running the LP library and making the other changes, the CR123 should have excellent battery life.



  • @a-lurker said:

    @axillent I'm in agreement.

    Me too, excellent clarification! πŸ™‚



  • @clippermiami said:

    I have a good solid 3.3V on the radio Vcc so it isn't a voltage drop problem. I'm wondering if there is a problem with the radio sitting over the PCB ground plane. I have one of the Seeed Studio DevDuino v 2.0 units an the radio also sits over the ground plane on that device. I haven't gotten around to programming it yet so I can't compare the performance.

    I think problem could be on the step-up regulator. It as been reported some regulators behave badly on nrf24 peak/burst operation.
    On those moments instant current needs are above normal and the VCCout from the regulator oscillates terribly.

    As a test, please use the capacitor workaround and check if problem still occurs.


  • Hero Member

    @BSoft Thanks. I'll try jumping around the up-regulator and see if that helps



  • @clippermiami
    You can still use the step-up, connect the capacitor in parallel between VCCout (regulator) and ground.

    Or better, connect the capacitor between VCC-GND on the NRF24 (the closest you get to nRF24 is better).

    If you still get transmission problems and if possible, bypass the step-up and keep the capacitor on and check again.


  • Hero Member

    @BSoft I jumpered around the up-regulator and it didn't make any difference, I still cannot get updates from the kitchen, about 30 feet and one wall from the gateway. So far the only thing that has made a difference is the NRF with the SMA antenna.


  • Hero Member

    @BSoft re: Capacitor Bypass. I assume you are talking about the 4.7uFd cap between the Vcc and Gnd on the radio? If so its been installed from the get-go, its part of the design and is within millimeters of the NRF connector.



  • Ok, since sma antenna is more power demanding and works ok, maybe capacitor isn't solution.

    But i get better than 30 feet on zigzag antenna, maybe you have a not so perfect pcb unit (nRF). It is nice and residue clean?


  • Hero Member

    @BSoft I've tried several different ones, theyt all look clean, no "gunk" or anything. I even tried taking it off the board and putting it on a extension cable, same results.Yeah, 30 feet seems a bit of a drag πŸ™‚

    john



  • @clippermiami said:

    @BSoft re: Capacitor Bypass. I assume you are talking about the 4.7uFd cap between the Vcc and Gnd on the radio? If so its been installed from the get-go, its part of the design and is within millimeters of the NRF connector.

    Yes it is!

    Sorry i wasn't aware of 4.7uF presence.

    You could add more since it as been reported as better (220Β΅F), check here: link text


  • Hero Member

    @BSoft Interesting discussion. Bottom line seem to be that 4.7 uF doesn't do much, the more the merrier then.


  • Hero Member

    It's not just about capacity, it's about using a capacitor with low ESR.


  • Hero Member

    Are you trying different orientations of the antenna? While I've not seen any spec's for the cheap module antenna ("7" shape or zigzag), I think I recall seeing reference to a pattern with two peak lobes and two nulls for another nRF24L01+ or nRF51822 based module. It's unlikely that the antenna is omnidirectional. (I don't know if the antenna also has polarization issues, another possibility).


  • Hero Member

    @Zeph I changed orientation buy door of "incidentally" , I held the unit up over my head to see if I got updates and I did, more often than just sitting on the counter but still not all the time. In this case the antennas would have been vertical rather than horizontal. Puzzling to be sure.


  • Mod

    about capacitor for radio. Attached you can see picture from one of my successful project
    capacitor is tantalum 22uF soldered directly to pins of the module, from the side of module PCB
    you can see capacitor as a small yellow box on top of the 8 pin radio connector
    Ρ„ΠΎΡ‚ΠΎ111.JPG


  • Hero Member

    @axillent Do you have a feel for the range of this rig? If this is the answer I'll get the capacitor and mod every radio πŸ™‚

    My Gateway has the SMA antenna on it and is less than 30 feet, and one interior wall, from the sensor and it doesn't work. When I bring the sensor to within about 10-12 feet it works every time but out at 20+ feet it fails almost every time. Its hard to believe that there is so little range

    I've tried a number of things:
    (a) several different radios - no change
    (b) remove the radio and place it on a 8 inch cable to get away from the ground plane - no change;
    (c) jumpered around the up-regulator (i.e. everything direct connected to battery) - no change;
    (d) radio with SMA antenna - works every time but the battery consumption goes through the roof. In 12 hours with the SMA antenna the battery dropped 0.12 V versus 0.04 V in 24 hours with the regular radio. The AMP on the antenna version consumes a lot of juice.

    Puzzlement πŸ™‚


  • Mod

    @clippermiami My distances are not too long, Just measured - this particular device is ranged 5m with one wall on the way to gateway
    you have to distinguish radio with SMA **without **PA&LNA and radio **with **SMA and with PA&LNA
    last one have an additional chip to amplify radio signal both way

    radio without PA & LNA with SMA can sometimes be worse comparing to radio with PCB antenna
    it depends on how well external antenna is aligned by frequency and impedance

    List of your actions have radio channel tuning missed


  • Hero Member

    @axillent This SMA unit has the PA on it. The radio channel is the default for everything.

    You distance is similar to mine, about 4.5-5 meters with one wall and it works. Beyond that NADA πŸ™‚


  • Mod

    @clippermiami

    @clippermiami said:

    @axillent This SMA unit has the PA on it. The radio channel is the default for everything.

    works and works the best way are different things, If you live far from big cities probably it make no sense.
    Otherwise it is recommended to run network scan from RF24 examples to find less busy channel at your location.


  • Hero Member

    @axillent The wireless channel is the one thing I hadn't investigated as yet so i will. I suppose it could be congested around here.


  • Hero Member

    I ran the scanner but got page after page of:

         RF24/examples/scanner/
    
         Scanning all available frequencies...Scan completed.
         Scanning all available frequencies...Scan completed.
         Scanning all available frequencies...Scan completed.
         Scanning all available frequencies...Scan completed.
    

    My radio is configured exactly as described although I will admit i just loaded the sketch to the sensor board and ran it on there rather than set up a special build just for that.
    :


  • Mod

    @clippermiami do not knew why but there are a few versions of this example
    try this one

    sorry, do not knew how to insert a code here

    /*
     Copyright (C) 2011 James Coliz, Jr. <maniacbug@ymail.com>
     Copyright (c) 2012 Greg Copeland
    
     This program is free software; you can redistribute it and/or
     modify it under the terms of the GNU General Public License
     version 2 as published by the Free Software Foundation.
     */
    
    /**
     * Channel scanner
     *
     * Example to detect interference on the various channels available.
     * This is a good diagnostic tool to check whether you're picking a
     * good channel for your application.
     *
     * Inspired by cpixip.
     * See http://arduino.cc/forum/index.php/topic,54795.0.html
     */
    
    #include <SPI.h>
    #include "RF24.h"
    #include "printf.h"
    
    // Only display active frequencies
    static const bool activeOnly = true ;
    
    //
    // Hardware configuration
    //
    
    // Set up nRF24L01 radio on SPI bus plus pins 8 & 9
    
    RF24 radio(9,10);
    
    //
    // Channel info
    //
    
    const short num_channels = 128;
    short values[num_channels];
    uint8_t signalMeter[55] ;
    
    //
    // Setup
    //
    
    void setup(void)
    {
      //
      // Print preamble
      //
    
      Serial.begin(115200);
      printf_begin();
      printf("\n\rRF24/examples/scanner/\n\r");
    
      //
      // Setup and configure rf radio
      //
    
      radio.begin();
      radio.powerUp() ;
      radio.setAutoAck(false);
    
      // Get into standby mode
      radio.openReadingPipe( 0, 0xFFFFFFFFFFULL ) ;
      //  radio.setDataRate( RF24_250KBPS ) ; // may fallback to 1Mbps
      radio.setDataRate( RF24_1MBPS ) ; // may fallback to 1Mbps
      radio.startListening() ;
      radio.stopListening() ;
    }
    
    //
    // Loop
    //
    void loop(void)
    {
      // Clear measurement values
      memset( values, 0x00, num_channels ) ;
      printf( "Scanning all available frequencies..." ) ;
    
      // Repeatedly scan multiple channels
      for( int channel=0 ; channel < num_channels; channel++ ) {
        radio.setChannel( channel ) ;
    
        // Amplify the signal based on carrier bandwidth
        int ampFactor ;
        for( int amp=0; amp <= 300; amp++ ) {
          // Alternate data rates
          ampFactor = amp%3 ;
          switch( ampFactor ) {
          case 0:
    	radio.setDataRate( RF24_250KBPS ) ;
    	break ;
    
          case 1:
    	radio.setDataRate( RF24_1MBPS ) ;
    	break ;
    
          default:
    	radio.setDataRate( RF24_2MBPS ) ;
    	break ;
          }
    
          // Listen for carrier
          ampFactor++ ;
          radio.startListening() ;
          delayMicroseconds( 6 - ampFactor ) ;
          radio.stopListening() ;
    
          // Was carrier detected? If so, signal level based on bandwidth
          if( radio.testRPD() ) {
    	values[channel] += ampFactor ;
          }
        }
      }
    
      // Now display our results
      printf( "Scan completed.\r\n" ) ;
      for( int channel=0 ; channel < num_channels; channel++ ) {
        if( !activeOnly || (activeOnly && values[channel] > 0) ) {
          memset( signalMeter, '*', min( values[channel], 54 ) ) ;
          signalMeter[min(values[channel], 54)] = 0x00 ;
          printf( "%03d (%4dMhz): %02d - %s\r\n",
    	      channel,
    	      2400+channel,
    	      values[channel],
    	      signalMeter ) ;
    
          // Reset the scanned value since its already beend displayed
          values[channel] = 0 ;
        }
      }
    }
    
    // vim:ai:cin:sts=2 sw=2 ft=cpp

  • Hero Member

    @axillent First thing I see is that this version has the radio on pins 8,9 whereas the version I used has it on pins 9,10 which is where it is in my hardware.


  • Mod

    @clippermiami That is a good point. But something tells me that you do need an assistance to adjust this code to your hardware πŸ™‚


  • Hero Member

    @axillent I won't deny that, but it seems simple enough. πŸ™‚


  • Hero Member

    So i breadboarded a Nano and a NRFL2401 with a PA and antenna, uploaded the scanner sketch and this is what I got: I'm using the default radio channel from the distribution library.

     RF24/examples/scanner/
     Scanning all available frequencies...Scan completed.
     000 (2400Mhz): 96 - ******************************************************     
     001 (2401Mhz): 100 - ******************************************************
     002 (2402Mhz): 95 - ******************************************************
     003 (2403Mhz): 99 - ******************************************************     
     004 (2404Mhz): 98 - ******************************************************
     005 (2405Mhz): 104 - ******************************************************
     006 (2406Mhz): 91 - ******************************************************
     007 (2407Mhz): 95 - ******************************************************
     008 (2408Mhz): 98 - ******************************************************
     009 (2409Mhz): 96 - ******************************************************
     010 (2410Mhz): 96 - ******************************************************
     011 (2411Mhz): 86 - ******************************************************
     012 (2412Mhz): 89 - ******************************************************
     013 (2413Mhz): 94 - ******************************************************
     014 (2414Mhz): 95 - ******************************************************
     015 (2415Mhz): 92 - ******************************************************
     016 (2416Mhz): 93 - ******************************************************
     017 (2417Mhz): 92 - ******************************************************
     018 (2418Mhz): 99 - ******************************************************
     019 (2419Mhz): 85 - ******************************************************
     020 (2420Mhz): 99 - ******************************************************
     021 (2421Mhz): 96 - ******************************************************
     022 (2422Mhz): 90 - ******************************************************
     023 (2423Mhz): 98 - ******************************************************
     024 (2424Mhz): 85 - ******************************************************
     025 (2425Mhz): 99 - ******************************************************
     026 (2426Mhz): 100 - ******************************************************
     027 (2427Mhz): 95 - ******************************************************
     028 (2428Mhz): 95 - ******************************************************
     029 (2429Mhz): 90 - ******************************************************
     030 (2430Mhz): 95 - ******************************************************
     031 (2431Mhz): 96 - ******************************************************
     032 (2432Mhz): 95 - ******************************************************
     033 (2433Mhz): 91 - ******************************************************
     034 (2434Mhz): 93 - ******************************************************
     035 (2435Mhz): 97 - ******************************************************
     036 (2436Mhz): 104 - ******************************************************
     037 (2437Mhz): 99 - ******************************************************
     038 (2438Mhz): 92 - ******************************************************
     039 (2439Mhz): 96 - ******************************************************
     040 (2440Mhz): 94 - ******************************************************
     041 (2441Mhz): 100 - ******************************************************
     042 (2442Mhz): 92 - ******************************************************
     043 (2443Mhz): 100 - ******************************************************
     044 (2444Mhz): 110 - ******************************************************
     045 (2445Mhz): 92 - ******************************************************
     046 (2446Mhz): 111 - ******************************************************
     047 (2447Mhz): 99 - ******************************************************
     048 (2448Mhz): 98 - ******************************************************
     049 (2449Mhz): 93 - ******************************************************
     050 (2450Mhz): 97 - ******************************************************
     051 (2451Mhz): 99 - ******************************************************
     052 (2452Mhz): 93 - ******************************************************
     053 (2453Mhz): 96 - ******************************************************
     054 (2454Mhz): 93 - ******************************************************
     055 (2455Mhz): 94 - ******************************************************
     056 (2456Mhz): 106 - ******************************************************
     057 (2457Mhz): 101 - ******************************************************
     058 (2458Mhz): 94 - ******************************************************
     059 (2459Mhz): 106 - ******************************************************
     060 (2460Mhz): 91 - ******************************************************
     061 (2461Mhz): 96 - ******************************************************
     062 (2462Mhz): 98 - ******************************************************
     063 (2463Mhz): 100 - ******************************************************
     064 (2464Mhz): 107 - ******************************************************
     065 (2465Mhz): 101 - ******************************************************
     066 (2466Mhz): 93 - ******************************************************
     067 (2467Mhz): 90 - ******************************************************
     068 (2468Mhz): 102 - ******************************************************
     069 (2469Mhz): 103 - ******************************************************
     070 (2470Mhz): 95 - ******************************************************
     071 (2471Mhz): 102 - ******************************************************
     072 (2472Mhz): 99 - ******************************************************
     073 (2473Mhz): 94 - ******************************************************
     074 (2474Mhz): 97 - ******************************************************
     075 (2475Mhz): 105 - ******************************************************
     076 (2476Mhz): 97 - ******************************************************
     077 (2477Mhz): 92 - ******************************************************
     078 (2478Mhz): 103 - ******************************************************
     079 (2479Mhz): 94 - ******************************************************
     080 (2480Mhz): 98 - ******************************************************
     081 (2481Mhz): 99 - ******************************************************
     082 (2482Mhz): 103 - ******************************************************
     083 (2483Mhz): 98 - ******************************************************
     084 (2484Mhz): 89 - ******************************************************
     085 (2485Mhz): 97 - ******************************************************
     086 (2486Mhz): 94 - ******************************************************
     087 (2487Mhz): 97 - ******************************************************
     088 (2488Mhz): 92 - ******************************************************
     089 (2489Mhz): 101 - ******************************************************
     090 (2490Mhz): 98 - ******************************************************
     091 (2491Mhz): 99 - ******************************************************
     092 (2492Mhz): 92 - ******************************************************
     093 (2493Mhz): 88 - ******************************************************
     094 (2494Mhz): 95 - ******************************************************
     095 (2495Mhz): 92 - ******************************************************
     096 (2496Mhz): 95 - ******************************************************
     097 (2497Mhz): 95 - ******************************************************
     098 (2498Mhz): 90 - ******************************************************
     099 (2499Mhz): 100 - ******************************************************
     100 (2500Mhz): 94 - ******************************************************
     101 (2501Mhz): 107 - ******************************************************
     102 (2502Mhz): 90 - ******************************************************
     103 (2503Mhz): 95 - ******************************************************
     104 (2504Mhz): 105 - ******************************************************
     105 (2505Mhz): 99 - ******************************************************
     106 (2506Mhz): 101 - ******************************************************
     107 (2507Mhz): 100 - ******************************************************
     108 (2508Mhz): 103 - ******************************************************
     109 (2509Mhz): 99 - ******************************************************
     110 (2510Mhz): 99 - ******************************************************
     111 (2511Mhz): 92 - ******************************************************
     112 (2512Mhz): 90 - ******************************************************
     113 (2513Mhz): 96 - ******************************************************
     114 (2514Mhz): 102 - ******************************************************
     115 (2515Mhz): 96 - ******************************************************
     116 (2516Mhz): 91 - ******************************************************
     117 (2517Mhz): 98 - ******************************************************
     118 (2518Mhz): 95 - ******************************************************
     119 (2519Mhz): 101 - ******************************************************
     120 (2520Mhz): 104 - ******************************************************
     121 (2521Mhz): 93 - ******************************************************
     122 (2522Mhz): 98 - ******************************************************
     123 (2523Mhz): 98 - ******************************************************
     124 (2524Mhz): 96 - ******************************************************
     125 (2525Mhz): 95 - ******************************************************
     126 (2526Mhz): 94 - ******************************************************
     127 (2527Mhz): 96 - ******************************************************
    

    Which does not look much like the display at the reference: http://arduino.cc/forum/index.php/topic,54795.0.html

    and i'm not sure what its telling me other than some relative signal level data. Perhaps someone could help me interpret this πŸ™‚

    Updagte:
    As it continues to run it shows significantly different values over time, some reaching as high as

     063 (2463Mhz): 84 - ******************************************************
     064 (2464Mhz): 89 - ******************************************************
     065 (2465Mhz): 97 - ******************************************************     
     066 (2466Mhz): 201 - ******************************************************
     067 (2467Mhz): 252 - ******************************************************
     068 (2468Mhz): 300 - ******************************************************
     069 (2469Mhz): 284 - ******************************************************

  • Hero Member

    I'm about idea'd out. I put a 200 uF electrolytic directly on the Vcc and Gnd terminals of the radio module and it made no difference whatsoever ... the sensor fails to report beyond about 10 meters and one interior wall. That doesn't leave much upside.

    I'm at a loss at this point, I've tried different radio modules to no avail. I've taken the radio off the board ground plane to no avail.Thus far the only thing I've found that allows decent distance is a radio with the PA/SMA antenna and that simply eats battery. I can't make hide nor hair out of the scanner output ... the channel variation doesn't appear to be more than a few percent for the most part so it doesn't look like that's much of a solution.

    I admit to being curious if anyone has actually had these things work beyond the workbench πŸ™‚


  • Mod

    @clippermiami said:

    I admit to being curious if anyone has actually had these things work beyond the workbench πŸ™‚

    Maybe your house is just a lot bigger than ours 🏒 πŸ˜†


  • Hero Member

    @Yveaux While I suppose that's possible 10-15 feet is still 10-15 feet πŸ™‚


  • Hero Member

    @clippermiami said:

    I'm about idea'd out. I put a 200 uF electrolytic directly on the Vcc and Gnd terminals of the radio module and it made no difference whatsoever ... the sensor fails to report beyond about 10 meters and one interior wall.

    Do you know what's inside that one interior wall? Could it have anything which would interfere with RF (more than the typical wood 2x4's and two sheets of drywall do)?

    Some people have definitely had better results.

    I think you said that you had changed out the radio module, but did you try any from a different source or batch?


  • Hero Member

    @Zeph it's just ordinary drywall. In the interest of complete disclosure, there is a floor-ceiling bookcase on the wall but if this stuff is THAT sensor then ... πŸ™‚

    The radios are all from an order about a month ago so they are probably the same batch. I have another batch of 10 coming but that's probably a week away yet.

    About the only thing left is to change radio channels but the numbers the scan don't tell me much, they don't vary but a few percent, so I am at a loss where to go.


  • Mod

    @clippermiami I hope to release a network sniffer for NRF24 in the near future which might probably help you to diagnose the problem. It captures all on-air packets and also shows which ones have CRC errors.
    The amount of packets with CRC errors is a good indication of the link quality.


  • Hero Member

    @Yveaux thanks, I look forward to it πŸ™‚


  • Hero Member

    @clippermiami: How about ACI, Adjacent Channel Interference?

    Having a WiFi background I know the 2.4 GHz band is also used by others, microwave oves, WiFi, Bluetooth etc.

    Been working on WiFi - Bluetooth coexistence and although they do not share channels, Bluetooth transmitting on 10 dBm can impact WiFi dramatically if the separation of the two devices is small.

    You could try moving both devices at least 5 meters away from other equipment and see if it makes a difference.


  • Hero Member

    @daulagari A possibility. I have three separate Wifi Access Points running in the house two 2.4 GHz 802.11n and one 5 GHz 802.11a. The 11A and one of the 11N points are in a dual band device, the other 11N is part of my AT&T uVerse router. I have them forced to specific channels, but none of then adjacent to the MySensors default (CH 76 as I recall), the highest one is the 11A on Ch 36


  • Hero Member

    I did have a chance for one more experiment. I had a SEEED "DevDuino" I bought to play with but haven't used yet. I swapped the radio from that module onto my sensor board and I was able to get reporting from another 10 feet away so there is definitely something related to the individual NRF24L01 modules --- different batch I guess. It still doesn't get me to even the other end of the house (perhaps 20 meters from the GW) let alone outside anywhere.or through outside walls.


  • Hero Member

    @clippermiami said:

    I have them forced to specific channels, but none of then adjacent to the MySensors default (CH 76 as I recall), the highest one is the 11A on Ch 36

    The NRF24 channels (Freq [MHz] = 2400 + channel) are not the same as WiFi channels. Ch 36 for WiFi is in the 5GHz band but can you share the 11n channels you forced the AP's to?

    See also https://en.wikipedia.org/wiki/List_of_WLAN_channels for a list of WiFi channels and their frequencies.


  • Hero Member

    @daulagari Yes, my error, 36 is in the 5GHz band.

    The 2.4 GHz channels are 5 and 11. There are some neighbors' Wifi on Ch 1 and 2 but they are heavily attenuated.


  • Hero Member

    It occurred to me that the one thing I had not changed was the GW radio. I had one spare NRF24L01+PA+SMA so I swapped it in the GW. That appears to be the fix --- I can now see the sensor module all the way out in the yard at the far end of the house, through outside walls and a half dozen interior walls. I doubt i'll get the 450+ meters reported elsewhere on the forum but its a LOT better than the 10 feet I was getting πŸ™‚


  • Admin

    @clippermiami

    Sounds good!


  • Hero Member

    @hek just my luck, the USB on my Vera Lite has packed up so now I can"t do any more testing until I sort that out. Maddening



  • I plan to use also a CR123 for my board. I bought some CR123a rechargeable on ebay but the battery give me 4V when it's charged... is it a problem to give 4V to a 3.3V step up converter? is the "a" after CR123 say that's a 3.7V instead of a 3V or is it just because of the rechargable function? is your CR123 give also 4V when it's charged?

    Thank's so much

    Julien


 

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