💬 Distance Sensor

  • Admin

    This thread contains comments for the article "Distance Sensor" posted on MySensors.org.

  • Hi there, i've just got a couple JSN-SR04T distance ultrasonic sensors in the post today. Was excited to sit down and make up my first go at a distance sensor to measure our water tank level, but when i went in to the mysensors master directory to find the example sketch for distance sensor i couldn't find one. So i copied the one from https://www.mysensors.org/build/distance but this is an old version and when i complied it in the Arduino IDE i had an error come up not recognising "NewPing.h". Any pointers where to go from here please??

  • Admin

  • Thanks @hek for your prompt reply. I went there and downloaded the "MySensorsArduinoExamples". I still can't seem to get "DistanceSensor" sketch to compile. It's still looking for NewPing.h even though it's in the directory!

    What am I missing?


  • Admin

    Looks like you placed the NewPing library in the wrong place. Check the path in the Arduino IDE preferences.

  • Get this error

    C:\Users\Daan\AppData\Local\Temp\Rar$DIa0.647\DistanceSensor\DistanceSensor.ino: In function 'void setup()':

    DistanceSensor:53: error: 'getConfig' was not declared in this scope

    metric = getConfig().isMetric;

  • Mod

  • hi folks, has anyone ever tried/considered to run this sensor on a battery powered node? Does it make sense, what would be a good setup? I want to monitor a remote watertank where it's hard to get power to... Thanks for your expert thoughts on this!

  • Hero Member

    @jjk There should be no problem running it from a battery if you only want to check a few times a day and sleep the node in between, but depending on how often you want it to check the level you may need to also have a small solar panel perhaps.

    You might also like to search for some of the other threads on battery powered nodes for info on how to reduce power consumption.

    I have just installed an ultrasonic level on my tank last weekend but I have power there for the pump so the node runs all the time.

  • thanks, sounds good, I will give it a trg

  • i ran it but i see garbage in com monitor?? what is wrong?

  • I have a setup with a HC-SR04 connected to an Arduino Pro Mini via a cable of about 5m length As I'm getting inconsistent readings from the sensor, I was wondering if cable length could be an issue - and if so, what a possible workaround could look like. Any thoughts from the experts?

  • Mod

    @jjk did it work better when you used a shorter cable?

  • @Boots33 I had looked at the exact same scenario as jjk, and although the intended 3.3v rfm69 node is pre-designed for low consumption (Whisper), my problem lay in the ultrasonic (DYP-ME007Y mounted on a tube inserted through the concrete roof) for hourly reports as it is 5v, as is the SR04. They can be triggered by 3.3v but not run. The standby current of a 5v booster proved too much, so resorted to a 3v 33mA latching relay to fire it up. It has all been a design exercise to date, but if my calcs are correct the node should run for a year on 3 alkalines with the US running once every hour triggered by RTC.

  • @mfalkvidd that's a fair question... I tested the sketch and connectivity with dupont cables and my spontaneous answer would be, "yes". However, to be honest, I never really calibrated the distance readings nor did I do a long-term test in the lab setup, so I think the true answer is, " I don't know"...

    @zboblamont sounds like you figured it out?! Would you mind providing details on the relay you have used?

  • @jjk Kemet EC2-3SNU from memory, but I know Omron et al make them also, check on Mouser etc. as it is not heavy current. The point is to ensure it is a latching type, the 33mA consumption from memory is ca 30ms, reverse pin polarity to reset relay, other may have dual coil.

  • thanks @ zboblamont, I will have a look

  • @jjk As an afterthought - If large temperature fluctuations are not an issue (air expansion in a tube) and it is not dirty water, you might also consider using differential pressure sensors as these are reasonably easy and can operate directly at 3.3v, inc I2C.

  • @zboblamont thanks for putting more thoughts into this for me!
    As I'm just an motivated hobbyist (far from being expert in electronics), I've tried to switch the pro mini to a nano, in a hope that keeps me from dealing with the relay (new to me). My thought was that the 5V it provides should mitigate the issue - looks like it doesn't. So if the readings aren't getting more consistent with the 5V Nano, what else could be the issue?

  • @jjk Hey, no expertise here either, hobbyist also, I am just old school measure thrice cut once. To be clear, I am fixed on a low voltage node so the relay gives the US board a solid and separate 5v, as I read that some of these are power sensitive, and some folks had problems powering them from an Arduino. The US trigger is supposedly ok at 3v, I only need to voltage divide the signal to the Mini. But that is my scenario, low power reliability.

    In your situation, I would restore everything to completely original in a test space, use separate supplies and run checks. If the board is faulty the inconsistencies should still be there. If not, introduce each variable methodically to identify the cause.


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