While I’m logging data and waiting for it to become substantial enough to test another project with, I thought it would be nice to kill the time and start building some new sensors: motion, temperature and light.

My goal is to monitor the complete second floor. For the 3 bedrooms I want to monitor motion, temperature and light. The passage will only require motion and light, while measuring the humidity in the bathroom would be nice too.

So, for that I need the following:

• 5 * motion;
• 4 * temperature;
• 5 * light;
• 1 * humidity.

I already have the motion sensors (PIR), the temperature sensors (1-Wire DS18B20), light sensors (LDR), enough JeeNodes, so all I need is a new humidity sensor.

OK; the amount of sensors I want to use is a bit too much for a single JeeNode I guess. Maybe 2 JeeNodes will suffice? I didn’t do any math on this yet, but I don’t think a single JeeNode can do the job all on its own. 2 JeeNodes maybe, cause the temperature sensors can be on a single 1-Wire bus, so those sensors won’t use up much ports on the JeeNode; and maybe I can use an Analog Plug to measure the LDRs? We’ll see. But for now, I assume I’ll need more than 1 JeeNode. However, I don’t like to spend an XBee module on each of those JeeNodes, cause I want to keep it relatively low cost. Yeah I know, there are cheaper alternatives for XBee..

But wait, I’ve still got an Arduino Fio; I’ve bought it sometime in January, not for a specific purpose but just to have a look at it, and I never found a good use for it yet. This Fio is also based on the ATmega328P and runs at 3.3V and 8 MHz. And it also has an XBee socket and USB connector. And it’s getting old, gathering dust on the shelf…

Now why don’t I use this Fio as a ‘hub’, or ‘central node’? It shouldn’t be too hard to make the (1,2,..) JeeNodes talk to this Arduino Fio over a few wires and use the Fio to transmit all the sensor values to the Zigbee coordinator; now that would be nice! I could power this Fio with a small USB power adapter and run a few wires (for power and serial connection) to the JeeNodes. Maybe I could just as easily use 1 JeeNode per room; this leaves enough ports available for future expansion… well, let’s think this one over for some time!

Yesterday the Arduino Workshop that Lennart and I organized, took place in Velsen. Quite a day it was… Leaving home @ 06:45, picking up 2 hitchhikers and arriving at 09:40.

The workshop started with a presentation by Lennart, followed by handing over the kits and handouts to the participants. And then it didn’t take long before the tables were crowded with soldering irons, laptops, breadboards, ATMega’s, jumper wires and so on. For some this was the first time they ever had a soldering iron in their hands, others brought their own soldering iron with them; the level of experience was very broad. But, by helping each other, most people managed to create a breadboard Arduino with a blinking LED, and went home with a soldered Bridge Board, Room Board and JeeNode

During the day Jean Claude Wippler also demonstrated his reflow setup and I wanted to demonstrate the HomeSeer Integration of the JeeNodes. However, at the moment suprème, something went terribly wrong: my JeeNode, which had worked flawlessly the whole day and made Homeseer speaking “Motion” all the time, suddenly refused to work.. What a bummer! And nothing helped; rebooting the laptop, changing COM ports, nothing! Aargghh!!

It was 20:30 when I came back home. Enough for today… well, that’s what I thought during the 1st hour… but I just couldn’t cope with the fact that my demonstration didn’t go as planned. I just had to see it working again! So I took the JeeLink and JeeNode with me to my hobby room, booted my PC, hooked them up and started HomeSeer. Guess what… it worked, as if it had never stopped! I don’t recall inviting Mr. Murphy to our workshop, but apparently he did pay us a visit in the afternoon…

The description of how to get the HomeSeer integration working is all in the handout, so I’m sure all the participants that want to get this working will have no problem doing that at home.

Despite the fact that I was not able to demonstrate the Homeseer part, I’m looking back on a successful day on which I hope the participants have learned a lot – enough to catch the Arduino fever!

The Arduino workshop I mentioned before, is actually going to happen! This will be a busy day, for both the organizing party as well as the attendees! A short list of the things we will be doing during that day:

• Building an Arduino on a breadboard
• Soldering a JeeNode
• The Arduino IDE and testing the JeeNode
• Experimenting with sensors and actors
• Building a Room board
• HomeSeer integration.

Enough to fill a complete day I’d say!

For the HomeSeer integration we’ll be using a slightly modified version of JeeNode for HomeSeer. This script based solution will help the attendees to integrate the hardware they created into HomeSeer in a very simple way. And since all the source code is provided, everyone can extend and/or modify it so that it will fit their personal needs the way they want.

Although I’m not a HomeSeer user, I do have a HomeSeer license that was paid for by a fundraiser that took place earlier this year. So I can play with HomeSeer whenever I like without any dirty tricks while I’m working on the Plugins I created or when I’m doing stuff like this.

I soldered a new JeeNode v4, a Room Board, uploaded the JeeNode sketch and connected it to the AA Power Board:

JeeNode with Room Board

The JeeLink sketch was uploaded to the, eh, JeeLink, and I added an extra line to the HomeSeer startup script to get the JeeNode script running. After some initial configuration like setting the JeeLink COM port and some RF related settings, I was good to go:

HomeSeer Status

OK, it’s all working; I can see the Room Board sensors in HomeSeer. Now it’s time to upgrade the JeeNode sketch to make it more power usage aware, cause I assume that will be important for those who attend this workshop. Back at home, they’ll probably start creating their own battery powered sensors, so a good starting point is essential. And that’s what I’m working on right now.

Since i removed a bunch of MS13 sensors recently, i am missing some input on what is going on at several places in our home. So while i was making a list of things i need in the near future, i realized i should extend the motion sensors a bit more, or otherwise i would lose the dark/light sensor the MS13 provided. And why not add temperature as well; cause that would mean i could do without the Oregon sensors also. I mean, why use 2 sensor devices (one only for temperature and another one for motion and light) when you can combine it all into one? Let’s have a look at temperature…

I still have 10 DS1820 1-Wire sensors somewhere from the days when i started with Domotica, but i never used them; maybe now i finally found a purpose for them? Let’s connect a few to an Arduino and see if  i can get a temperature reading:

Arduino with 3 x DS1820

And of course, there’s a library to use 1-Wire devices with an Arduino.. so before i knew it, i was polling the temperature of 3 DS1820s

Addr:10 6C 5 CA 0 8 0 C3  Temp=25.50 grC
Addr:10 33 EC 3 1 8 0 E1  Temp=25.50 grC
Addr:10 FB 90 C9 0 8 0 1A  Temp=25.50 grC

Addr:10 6C 5 CA 0 8 0 C3  Temp=25.50 grC
Addr:10 33 EC 3 1 8 0 E1  Temp=25.50 grC
Addr:10 FB 90 C9 0 8 0 1A  Temp=25.50 grC

Addr:10 6C 5 CA 0 8 0 C3  Temp=25.50 grC
Addr:10 33 EC 3 1 8 0 E1  Temp=25.50 grC
Addr:10 FB 90 C9 0 8 0 1A  Temp=25.50 grC

Add an additional LDR and I’m done; ready to replace a large part of all my sensors: all remaining MS13s and most of my Oregon Scientific Temperature & Humidity sensors with my own

While i was quite happy yesterday with the new way i’m going to handle things on the JeeNode regarding the motion sensor (PIR), i already knew i wasn’t finished yet; this was nice, but only a first step.

Cause what i had created was an IRQ being fired when the input becomes low. Well, the PIR output becomes high when there’s motion detected, so this is unusable, actually. For a brief moment i considered using a transistor as a NOT gate to invert the PIR output, but there had to be an easier way. Why would you only be able to activate an External Interrupt when a pin becomes low?? I read some topics on various forums, but those were very contradictory; some said i could, some said otherwise. OK, in that case, i’ll sort it out myself .. cause i really need interrupts based on a rise or a change!

Page 71 of the ATmega datasheet learned me that INT0 and INT1 indeed have Interrupt Sense Control and it’s only a matter of setting the right bits in the External Interrupt Control Register A, aka EICRA:

Bit 3 and 2 of EICRA

So it can be done, only thing is to figure out how…

The Arduino attachInterrupt() function has a 2nd parameter with which you can control what triggers an interrupt; the values are the constants LOW, CHANGE, RISING and FALLING (found in wiring.h). So why didn’t that nice Sleep library i found earlier have this feature? All i can do is call this function:

void SleepClass::powerDownAndWakeupExternalEvent(uint8_t interruptNumber)
{
 attachInterrupt(interruptNumber, SleepClass::external_event_handler, LOW);
 set_sleep_mode_and_sleep(SLEEP_MODE_PWR_DOWN);
 detachInterrupt(interruptNumber);
}

OK; changing things in the library depending on the kind of Sense Control i need for a specific sensor type is not an option of course, so i added a 2nd parameter to that function:

void SleepClass::powerDownAnd...Event(uint8_t interruptNumber, int mode)
{
 attachInterrupt(interruptNumber, SleepClass::external_event_handler, mode);
 set_sleep_mode_and_sleep(SLEEP_MODE_PWR_DOWN);
 detachInterrupt(interruptNumber);

}

That’s better; now i can choose whatever Sense Control I want; I’ve checked all of them right away:

Sleep.powerDownAndWakeupExternalEvent(0, RISING);

What a surprise, its working, all of them! RISING is just what i need right now for the PIR; CHANGE is what i would need for a door sensor.

Now i’m already modifying libraries and I can even understand what

EICRA = (EICRA & ~((1 << ISC00) | (1 << ISC01))) | (mode << ISC00);

does… i wonder where or when (if ever) this will end…

But I’m still not finished! Cause with all this powering down going on, it has become increasingly hard to keep a notion of time; millis() has become useless cause how can i determine the time that has passed since the last power down? On the other hand, do i really need to know that? Time will tell

Having a first set of batteries empty wasn’t  funny.. they lasted only 7 weeks! Way to short. And i kept on thinking that it might not have been caused by a bad battery.. what could i do next? Wait another 7 weeks to find out that I’m wrong? Neh.. that didn’t feel the right thing to do; Power down as much as possible and use an external interrupt would possibly give the best results anyway, so why not start with that right now!

I started with attaching a push-button to an Arduino, using a pull-up resistor to keep the input high when the button isn’t pressed:

Arduino with push-button

After that i started reading about interrupts. Here’s a table that shows the Wake-up sources that are available in the various sleep modes:

ATmega48PA/88PA/168PA/328P Wake-up sources

Both things i need are available: INT0 and/or INT1 and the Watchdog Timer, so it was time to start sketching

After 5 different sketches with all the same miserable results (freezing Arduino), i finally found a sleep library that did exactly what i wanted. I combined this library with code i had found earlier regarding setting up and using the Watchdog Timer, and what i have now, is just what i need. Below a sample of the Serial Monitor output and here is the sketch that produced it.

39171 I'm awake, caused by the WDT
39205 Sleeping...
39327 I'm awake, caused by the WDT
39362 Sleeping...
39484 I'm awake, caused by the WDT
39519 Sleeping...
39640 I'm awake, caused by the WDT
39674 Sleeping...
39796 I'm awake, caused by INT0
Doing some work...finished!
40257 Sleeping...
40377 I'm awake, caused by INT0
Doing some work...finished!
40839 Sleeping...
40960 I'm awake, caused by INT0
Doing some work...finished!
41421 Sleeping...
41542 I'm awake, caused by the WDT
41577 Sleeping...
41698 I'm awake, caused by INT0
Doing some work...finished!
42160 Sleeping...
42280 I'm awake, caused by the WDT
42315 Sleeping...
42437 I'm awake, caused by the WDT
42472 Sleeping...
42593 I'm awake, caused by the WDT
42628 Sleeping...

etc. etc.

Cool stuff! Let’s see how we can change the motion sensor to make use of this!

Lennart Herlaar and me are really hooked up to all this Arduino(-compatible) stuff; we both started somewhere in September 2009 with our first ‘trials’. My first experiment was with an Arduino Duemilanove and some LEDs; resulting in instant addiction! Once you discover what can be done with this platform and how you can use it, every day new ideas and interesting projects pass by. Exciting!

We decided to see if we could share our enthusiasm with a larger group of Domoticans; cause there are a lot of Domotica related things you can do with the Arduino platform. Normally Domotica related hardware is quite expensive and closed, in the sence that every manufacturer creates its own proprietary protocol and tries to keep it a secret as much as possible; even changing it for the sole purpose of making all knowledge gathered by reverse engineering useless(!). Interaction between products of different companies is still very hard (if at all) to find – and most Domoticans are forced to use commercial Home Automation software like Homeseer to tie it all together. However, without a Plugin available for that special type of hardware you’d like to use, you’re practically doomed…

So when we started thinking about organizing an Arduino workshop for the members of the Domoticaforum Europe, we knew right away that we couldn’t do that without also supplying a Homeseer Plugin with it; well at least create a framework that would enable the workshop attendees to connect their new Arduino-based hardware to the most used HA software here in the Netherlands.

And that’s exactly what’s going to happen; when we get enough response (a mimimum of 15) to our post on the Domotica forum and we decide to go ahead with organizing this workshop, we’ll also have to start thinking about how to create an easy to use, flexible, future proof Plugin that can interface with the Arduino platform and it’s compatibles like (my favorite) JeeNodes..

It will be fun! As always

After my problems with the MS13 sensors yesterday, i managed to find some spare time (even though, or maybe because it was father’s day) to write a sketch for the new motion sensor i created during the last couple of weeks. Always taking one step at a time, i located the first prototype of this sensor at a place where i can see the enclosure LED from the living room: i want to know how it performs…

New motion sensor

Now powered by 3 rechargable NiCd batteries and with all hardware nicely put away in the enclosure. In due time the enclosure will be moved out of sight so only the PIR will be visible. I’ve decided to use 3.5 mm jack plugs to be able to disconnect the enclosure from the sensor, so i can easily take the enclosure back to my office, because i don’t think the JeeNode is already running the final version of the ‘PIR’ sketch…

A new class, 2 database records and 1 line of code were enough to get the sensor working in my Domotica system:

procedure TAMN31112.ProcessInterfaceData;
begin
  Pin(1).AsBoolean:= (O.Data[1]='1');
end;

The new PIR can be viewed from my website (it’s called BP PIR):

Battery powered PIR

The sketch is still under development; for instance, how much difference would it make if i change the DigitalRead() into a bitRead()? I’ll have to read more about that on JeeLabs … Other questions are: should i increase the heartbeat interval (currently 45 seconds) or the Motion report interval? Can i create some sort of battery power monitoring with the XBee? But that will all be investigated when i’ve finished building my second motion sensor based on JeeNode and XBee..

Now that my Zigbee/Jeenode equipped pressure sensor is working for 3 months without any problems, it was time to leave the breadboard stage and move on to something more permanent. While ordering new Jeenodes at Jean-Claude Wipplers shop, i stumbled upon a post (i should read his daily weblog more often!) that showed me just what i needed: an enclosure that looked just right for this job. I ordered the Jeenodes, 2 enclosures (1 extra for when i mess up the first one and don’t want to wait for a second delivery..) and some other handy stuff.

First i sawed off the part of the PCB that i didn’t need, to decrease it’s size.

JeeNode PCB size reduction

Guess what? Now the length of the PCB equals the internal width of the enclosure! Nice… I still had some battery holders laying around that also fitted quite well:

Enclosure, batt holder and JeeNode

I didn’t want to leave off the FTDI headers, so i used 6 straight headers and removed the plastic strip from the headers after the headers were soldered onto the PCB. With the plastic headers left on, the completed PCB was just a bit to wide for the enclosure, which caused tension and the enclosure wouldn’t close well anymore.

Next item that had to be prepared, was the XBee Breakout Board. Normally the top of this Breakout Board contains the 2mm XBee headers and the 0.1″ spaced headers are at the opposite side. I removed the bottom headers i soldered in when i used this board for other purposes and soldered 6 wires on it from the top, only for those pins i really needed:

XBee Breakout Board

Pin 1 (labeled Vcc) for Power, Pin 3  (labeled DIN) for transmission, Pin 9 (DTR) for controlling Sleep mode, Pin 10 (GND), Pin 11(CTS) and Pin 12 (ON) for the LED. This makes the Breakout board a lot thinner and the wires are coming out between the board and the XBee module.

After soldering the wires coming from the XBee board to the JeeNode, drilling a hole for the LED (which blinks when a pressure sample is being sent), soldering the wires and gluing the battery holder into the enclosure, it looked like this:

Almost done!

The FTDI headers are very handy now, for uploading the sketch with the JeeNode already inside the enclosure; cause all you have to do is open the enclosure, gently lift up the left side of the JeeNode and connect the cable. So whenever i need to upgrade the JeeNode, i don’t have to worry about connecting issues.

FTDI cable connected to the JeeNode

Now all there was left to do was moving the XBee module and the Pressure Plug from the Breadboard to their new ‘home’, add 4 batteries, click on the other half of the enclosure and.. my first WAF certified sensor was born!

Now that i have 2 JeeNodes up and running for more than a week and everything’s working fine, it’s time to do some calculations on power usage of the sensors. First thing i wanted to know was how much power a combination of a sensorless Jeenode and XBee module was using, so i created a sketch that would give me some ‘inside’ information about what was going on inside the Jeenode. The sketch i made informs me about a couple of things, like:

- the timespan the JeeNode is awake to power up the XBee, send a packet to the XBee and wait for it to finish transmission;

- the timespan the XBee is powered to send that packet of 10 bytes.

With these numbers i should be able to roughly calculate the power usage of this sensor. The power that is used by the JeeNode while it’s awake is about 35 mA, while the XBee uses around 40 mA while transmitting. When both the JeeNode and XBee are in deep sleep, the combination of both uses only 60 μA.

The time measurements i did to find out the timespans mentioned above gave me the following figures: the total time the JeeNode is awake to read a sample from the Pressure sensor, wake the XBee, transmit the data and go back to sleep is 40 ms. The time that the XBee is awake is around 25 ms. With a sample interval of 30 seconds, and a 2000 mAh battery, i have calculated a battery life of more than a year; increase the interval to 60 seconds (still good enough for this type of information) and batteries should survive more than 2 years… i think.

Just ask me in a year or so ..

But good enough to go ahead with the expedition!