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The end of the Forget Me Not Design Challenge is nearing ... But not before some last minute surprises and hiccups ...

I've been installing the electronics in the build and combining all components that were developed over the course of the project.

At this stage, this was mostly an integration task where the interaction between the different components was tested.


There were some pending tasks, things missing or even not working ... Let's have a look at what happened.



Hiccups & Surprises


Solenoid Valve


One of the things I overlooked for the water dispenser, is that the DC-DC step up converter driving the solenoid valve is triggered by a LOW signal on the enable pin and disabled with a HIGH signal.


This means that, when using the RPiSoC directly, I would flood the kitchen in case of a reset of the RPiSoC, because the pins are LOW by default. And since the Pi takes longer to boot and restore the default HIGH, I'd have a big problem ... As time was short, I went for a quick solution where I made a NOT gate using a transistor.

Screen Shot 2014-10-20 at 15.02.39.png


Perhaps there were better ways to do this (reprogramming default pin state of RPiSoC ?), but as I said, time was short and I had other issues to resolve as well.


Food Dispenser


The food dispenser prototype I had built early on didn't seem to work properly after all. The cat food was jamming and wouldn't dispense reliably. I had to come up with another idea, and fast.

To prevent the food getting stuck and not dispensing, I thought something should move inside the food container.


This is the new mechanism I've come up with:




It's not so nice looking, but it does the trick, and now the mechanism works reliably.


The software part of driving a servo with the RPiSoC could be reused, it's just the dispensing mechanism itself that changed.


Weighing Scales


This one is more of a silly mistake during assembly ...


While integrating all the different components in the build, it seems I mounted my load cells upside down. The result ?

Pushing/putting weight on the load cells didn't do anything. I was getting crazy: was it the hardware, or the software ? Why wouldn't it work anymore ?

Then I noticed that pulling the scale up was creating a reading. That's when I realised my mistake and mounted them correctly.


Some Little Things


There were some tasks that still required some attention. Even if they are small, they need to be done.




It's a small thing to be done, but relevant in order to be able to correlate things properly and easily.


Setting the timezone is very straightforward:


pi@webserver ~ $ sudo dpkg-reconfigure tzdata


This will launch a wizard, looking like this:

Screen Shot 2014-10-20 at 15.17.58.png


Afterwards, the changes are acknowledged:

Current default time zone: 'Europe/Brussels'
Local time is now:      Mon Oct 20 15:18:09 CEST 2014.
Universal Time is now:  Mon Oct 20 13:18:09 UTC 2014.


I did a small verification:

pi@webserver ~ $ date
Mon Oct 20 15:18:20 CEST 2014

pi@webserver ~ $ cat /etc/timezone


Et voila, correct timezone configured!




I've been developing the project using an ethernet connection to the Raspberry Pi. Since I started the build and mounted the Pi in the enclosure, I configured wifi for remote access.


By editing the interfaces file and adding the correct SSID and password, the Pi should be able to connect the the network.


pi@webserver ~ $ sudo nano /etc/network/interfaces

auto wlan0
allow-hotplug wlan0
iface wlan0 inet dhcp
        wpa-ssid "<your_ssid>"
        wpa-psk "<your_password>"


OpenHAB Notifications


I didn't have any notifications set up in openHAB, so I decided to give that a quick go.

michaelwylie has done a great job describing this for Android users, I'll quickly describe it for iOS users


iOS notifications can be achieved using "Prowl".


Some things are required for Prowl notifications with openHAB:

- an API key

- updating openhab.cfg

- a notification rule in openHAB

- the prowl action jar in the addons folder

- a Prowl client on the iOS device




This step is easy.


Go to Prowl - iOS Push Notifications and register for a free account. You can then generate an API key to be used by your application.

Screen Shot 2014-10-19 at 19.35.39.png




There are three parameters that need to be set in the openhab.cfg file for Prowl to work.

- the API key which was generated earlier

- a default priority


Screen Shot 2014-10-19 at 19.36.18.png

Don't forget to uncomment the lines by removing the "#" at the start of the line.


########################## Prowl Action configuration #################################
# the apikey for authentication (generated on the Prowl website)
prowl:apikey=<my generated key>

# the default priority of a Prowl notifications (optional, defaults to '0')

# the url of the Prowl public api
# (optional, defaults to '')


Note that the URL used is different than the default. I think the default value is obsolete, as the page is not accessible.




It seems there are multiple ways to define the pushNotification, so I tried them all to see which notification I would (or not) receive.


var Timer front_door_timer = null

rule "Front door"
when Item EnOcean_sensor_frontdoor changed
        if(EnOcean_sensor_frontdoor.state == OPEN) {
                if(front_door_timer==null) {
                        front_door_timer = createTimer(now.plusMinutes(5)) [|
                                pushNotification("Front door 1", "The front door has been open for 5 minutes! Is it supposed to be?")
                                pushNotification("<api_key>", "Front door 2", "The front door has been open for 5 minutes! Is it supposed to be?")
                                pushNotification("<api_key>", "Front door 3", "The front door has been open for 5 minutes! Is it supposed to be?", 0)
        else if(EnOcean_sensor_frontdoor.state == CLOSED) {
                if(front_door_timer!=null) {
                        front_door_timer = null


The first notification makes use of the API key and priority defined in the openhab.cfg file. The other two notifications override these values by defining the API key and or priority in the call.


What this rule does is the following:

- when the front door is opened, start a 5 minute timer

- if the front door is closed, abort the timer if it is still running

- if the door is still open when the timer reaches the end, a notification is sent




The prowl jar needs to be put in the openhab addons folder for it to work.


pi@webserver ~ $ ls -l /opt/openhab/addons/*prowl*
-rw-r--r-- 1 root root 59510 Jun 16 04:26 /opt/openhab/addons/org.openhab.action.prowl-1.5.0.jar




The client can be downloaded from the App Store. Unfortunately, it's not free ... But at $2.99 and for the sake of testing and being notified when something happens, I bought the app.

photo 1.PNG




As stated earlier, I defined 3 different notifications, each with a different set of parameters. I received all 3 of them, meaning that the syntax for each of them is valid, which is good to know.

The different syntaxes allow to experiment with different API keys or priorities depending on the notification.


The notifications appeared on my phone and the details could then be viewed:

photo 2.PNG


This last minute feature is working!


Camera & LEDs Mount


As part of the pet care system, I used a camera to be able to watch the cats while they eat or drink. Later on I also found a wide angle lens for that camera.

I needed a way to mount these, including some LEDs to light up the direct environment. To do all of this, I designed a bracket and 3D printed it ...


This is the result:

photo a.JPG



Pfiew, all those small changes and hiccups add up and become time consuming ... But, it's almost done and Friday is getting very close, *eek* !