New nrf24l01+ smd

[alexsh1]

Hello,

Anyone have used these tiny transceivers?
I'm struggling to find headers and other accessories

Cheers
Alex

[alexsh1]

[Oitzu]

@alexsh1 yeah they are not really new and well.. as you said, for smd mounting.
Here you can see the pinout: http://www.sunrom.com/media/content/404/dim.gif

[alexsh1]

@Oitzu I did not realise they are not new. However, my point is that I'd to know how these perform vs normal ones.

Also I can fit them into a very tight places. However, getting 0.05" (1.27mm) headers is a problem. Will be ordering some on aliexpress shortly if I manage to find them.

[Oitzu]

@alexsh1 in my tests they pretty much perform the same as the big modules.
Well.. afaik there are no headers for that. They are meant to soldered directly to pcb.

[Yveaux]

@alexsh1 You could use an adapter to prototype these.
In your final product solder them directly on the PCB or solder wires to them.

[alexsh1]

@Yveaux - This is an excellent find. Merci!

Thank you guys - my idea is to run Sensebender Micro with nrf24l01+ smd and a tiny CR3032 to save space. I'll probably need to use one of these adapters or use wires.

[AWI]

@alexsh1 in my experience with the small version they perform well. As soon as my skills allow it I will try to adapt 2AA slim design this is my current artwork.

[alexsh1]

@AWI I looked at your artwork some time ago, but decided to go for this node in terms of size and functionality.

As I said before, the plan is to have Sensorbender and this transceiver in a low power node

[AWI]

@alexsh1 mounting the SMD version of the radio with wires on the Sensebender would really make it small

From browsing OSH Park, I believe @GertSanders is experimenting with the SMD radio also (sorry Gert for lifting the lid)

[alexsh1]

@AWI Thanks - really great to know that @GertSanders has been already working on a SMD version.

I found another interesting adapter for 1.27mm nrf24l01+

https://oshpark.com/shared_projects/CtW4Xaow

[alexsh1]

By the way @GertSanders , is your SMD board similar to @m26872 one (http://forum.mysensors.org/topic/2067/my-slim-2aa-battery-node)?

[ahmedadelhosni]

Propably no difference. I have asked about it a week ago http://forum.mysensors.org/topic/2984/nrf24l01-mini-vs-normal-size-module

[GertSanders]

@AWI No problem, this board is making its way to me via the mail now (was shipped from OSH Park last wednesday).

I'm hoping to test it coming week.

This board one is a one-trick pony. It is based on @m26872's concept of a very narrow board, but in my case I just need it to handle 2 magnetic switches. So pull-up resistors and connection for two contacts (normally closed) is provided (on the pins that allow hardware wake up from power down), and nothing else. No crystal, just minimal power decoupling and a led. No FTDI adapter or ISP. And of course only connection for the SMD version of the NRF24.

While that was being made at OSH Park I prepared a second design, but this one is still in movement (not ordered yet), measurements are in mm:

It is certainly not a Sensebender, as it lacks ATSHA204A, SI7021 and SPIFlash, but it does have FTDI interface and optional pull-ups on D2 and D3. It is my first try at SMD, with 0805 size components (I need to be able to hand solder them).

The objective is to make a working sensor board as flat as possible. At the moment is is even smaller then the CR2032 batteryholder I was planning to use. A possibility is that I go for a two board approach using this "flat node" and a second board to hold a CR1632 (a holder for this smaller battery is in the image above, Keystone Technologies model 3013).

To be continued ...

[alexsh1]

@GertSanders said:

This board one is a one-trick pony. It is based on @m26872's concept of a very narrow board, but in my case I just need it to handle 2 magnetic switches.

This is what I was looking for as I need a small board for a reed switch. Please keep us posted about your testing

[meddie]

i like the first layou. Its just pretty narrow. ideal for housing in a cable duct. if there will be an atsha204, a flash modul and a battery sensor this would be the perfect node.

[alexsh1]

Let a fiddly job begin...

[Yveaux]

@alexsh1 those pliers seem to be the wrong size....

[alexsh1]

@Yveaux yeah, I know - I placed an order today for a new set of cutters on Amazon

[AWI]

@alexsh1 don't mount it in the wrong direction...

[alexsh1]

@AWI you mean nrf24l01+? I have to check what the best fit is given I'll have a few wires

[AWI]

@alexsh1 this is what I did. Mount it in the same direction as the original

[alexsh1]

@Yveaux are these much better now? ;)))

[alexsh1]

@AWI Now I see what you mean! Thanks for heads up - really appreciated it. This is the first time I'm dealing with this transceiver in SMD

[Yveaux]

@alexsh1 much less of a challenge

[GertSanders]

@alexsh1 My very narrow board was built and tested today. It works fine, I posted info on the hardware forum.

I must say I feel pity for this sliver of plastic and metal ...

[alexsh1]

@GertSanders said:

@alexsh1 My very narrow board was built and tested today. It works fine, I posted info on the hardware forum.

I must say I feel pity for this sliver of plastic and metal ...

Excellent! I ordered your narrow board a few days ago as I thought it would be very useful.

One thing I can tell for sure - cutters are really well built. They are made in Japan and electrostatic safe. Most important they are not big as the ones I had before.

[Sweebee]

ordered the pro mini shields and I'm not disappointed As small as you can get:

[Yveaux]

@Sweebee Very nice indeed!
I'm very surprised btw that you're using 2xAA to power the PIR. Will it work reliably (no false detections), even when the batteries are running out?
I use 2xAA to power Pro Mini + nRF and an extra AA to power the PIR. This way the supply to the PIR will stay > 3V over time.

[Sweebee]

@Yveaux the pirs work fine if you only have interrupts with CHANGE. I don't use a sleep timer. If you wake it up every minute or so its unreliable yes. but only with interrupts from the pir it works fine. I have 10 pirs like this. Oldest one is from march 2015 and still running.

[Yveaux]

@Sweebee Consider yourself lucky then! I have the same issues decribed here when powering using 2xAA.
I ditched the step-up converter as it introduces too much noise and reduces battery life. The 3xAA solution seems to work reliably though.

[alexsh1]

@Sweebee

You have an excellent setup - I ordered those adapter as well at oshpark.
@Yveaux has got a point - I have been struggle to build a reliable PIR on 2xAA batteries. I have just started building it now. 1 year battery life and counting is impressive.

@Sweebee Would you care to share your code? Maybe there is anything there which gives us some clues though I believe this is more a hardware issue.

[Yveaux]

@alexsh1 said:

Would you care to share your code? Maybe there is anything there which gives us some clues though I believe this is more a hardware issue.

Agree. Apparently @Sweebee made modifications to the PIR (mainly to move some capacitors, judging from the photos) but maybe you did some more to improve battery life/stability?

[Sweebee]

I removed the left capacitor since it's not needed in 3.3v hack. And I moved the right one because otherwise it didn't fit into the case.

My sketch:

#include <MySensor.h>
#include <SPI.h>
#include <readVcc.h>

// ********** CONFIG **********************************

    #define NODE_ID AUTO          // ID of node
    #define CHILD_ID 1            // ID of sensor
    #define PIR_PIN 3             // Pin connected to the PIR
    
    #define MIN_V 2000            // empty voltage (0%)
    #define MAX_V 3200            // full voltage (100%)

// ****************************************************

MyMessage msg(CHILD_ID, V_TRIPPED);
MySensor node;

int oldBatteryPcnt;
int sentValue;
int forceSend = 0;

void setup()
{
  node.begin(NULL, NODE_ID, false);
  node.sendSketchInfo("PIR Sensor", "1.2");
  node.present(CHILD_ID, S_MOTION);
  pinMode(PIR_PIN, INPUT);
  digitalWrite(PIR_PIN, HIGH);
}

void loop()
{
  
  // Get PIR
  int value = digitalRead(PIR_PIN); // Get value of PIR
  if (value != sentValue) { // If status of PIR has changed
    resend(msg.set(value), 5); // Send PIR status to gateway
    sentValue = value;
  }

  // Send batterylevel
  sendBattery(); 

  // Sleep until something happens with the sensor
  node.sleep(PIR_PIN-2, CHANGE); 
}

// FUNCTIONS

void sendBattery() // Send battery percentage to GW
{
  forceSend++;
  int batteryPcnt = min(map(readVcc(), MIN_V, MAX_V, 0, 100), 100); // Get VCC and convert to percentage      
  if (batteryPcnt != oldBatteryPcnt || forceSend >= 20) { // If battery percentage has changed
    node.sendBatteryLevel(batteryPcnt); // Send battery percentage to gateway
    oldBatteryPcnt = batteryPcnt; 
    forceSend = 0;
  }
}

void resend(MyMessage &msg, int repeats) // Resend messages if not received by GW
{
  int repeat = 0;
  int repeatDelay = 0;
  boolean ack = false;

  while ((ack == false) and (repeat < repeats)) {
    if (node.send(msg)) {
      ack = true;
    } else {
      ack = false;
      repeatDelay += 100;
    } 
    repeat++;
    delay(repeatDelay);
  }
}

[Yveaux]

@Sweebee Only real difference I see compared to my sketch is that I'm using a timeout when sleeping, so the watchdog stays enabled while sleeping.
According to the datasheet, the AtMega power consumption is roughly 4.7uA vs 0.6uA in powerdown mode with/without watchdog enabled:

This is a significant difference, but when including the PIR & nRF in the total power consumption it is only a small part.

[Maciej Kulawik]

@Sweebee I see in the sketch, that you are enabling internal pull-up on PIR input. This means, that if PIR is not detecting movement and its output is set to zero, this pull-up resistor consumes 60uA (in the best case).

[Sweebee]

@Maciej-Kulawik in my calculations it is 6uA. The pirs use around 15-20 uA in sleep.

[Maciej Kulawik]

@Sweebee Depending on value of these pull-up resistors. I have read that they have about 50k, so with vcc=3v you will get 60u.

[Sweebee]

@Maciej-Kulawik removed the pull-up and they are all working fine Don't know why i have added it, in one of my oldest sketches i havent enabled it.