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46  Using Arduino / Project Guidance / Re: my external watchdog circuit for Arduino on: March 03, 2012, 10:30:27 am
Nope, not a Mega2560. A standard Duemillanove.
Funny you should mention the built-in watchdog. I tried to find conclusive info on that but was not able to. Most of what I found were reported problems with the built-in one. And it seemed I would need some specific bootloader. So I decided to make my own...

Did you get the internal one working reliably? Any links you could provide showing how to use the internal one?
47  Topics / Home Automation and Networked Objects / Re: The best way to do home automation? on: March 02, 2012, 11:00:45 am
Yes, I did the same. Removed the shell and put it in a slightly bigger case that houses the PSU, an Arduino Mini and a Bluetooth module or RF1100-232 module. Then there is a DHT11 sensor glued to the outside. The whole thing plugs into a power socket just like a wall PSU. 2 pictures attached. All that hot melt glue is mostly for safety. I didn't want any mains power exposed.... ;-)

What we would need is a very small switch mode PSU, say, the size of a small relay. Does something like this exist?
48  Using Arduino / Project Guidance / my external watchdog circuit for Arduino on: March 02, 2012, 06:51:19 am
I hope this the right topic to post this. It's not a request for help but rather to show how I've done it hoping it could be useful for others.

Some time ago I built an Arduino based weather station that can be read via SNMP (Agentuino library) through the Ethernet shield. There were some issues with either the Agentuino or Ethernet libraries where the Arduino would crash when it receives a non-SNMP packet. I never figured out how to fix that, so what I've done is building a watchdog circuit.

The watchdog is a rather simple 555-based timer circuit. The output stays high indefinitely as long as the circuit keeps getting pulses on its input within a certain amount of time.
With the resistor and capacitor values in the attached circuit that time is about 3 seconds. If there has been no pulse on the input for more than 3 seconds (e.g. when the Arduino crashes), then the watchdog output goes low. When connected to the Arduino's reset pin, this will reset the Arduino. The output will then go high and low in intervals until a pulse on the input has been received. This means that the Arduino will keep resetting until there are pulses again.

The timing can of course be changed according to the requirements of your project by changing the values for R1, R2 and C1. You can use a 555 calculator to work out the values you need to use.

One more thing.. I did try without the opto-coupler first, (just with a transistor) but I had rather odd results. I had the 4N25 lying around so I use it and everything became stable. If anyone has a suggestion how to do this without the opto-coupler, please post it here.

The schematic diagram is attached.

Chris
49  Topics / Home Automation and Networked Objects / Re: The best way to do home automation? on: March 02, 2012, 06:28:36 am
I'm also currently working on my own home automation project. I'm using the Arduino Mini (Pro) because of its tiny size. They are quite cheap too, so I will have many of them around the house; one per device I want to control. (I find this better than running long cables from a single Arduino to all devices around the house).
Then I'm using either Bluetooth modules or RF1100-232 433MHz RF wireless modules to send and receive serial commands to/from the Arduinos. (I'm actually now moving away from Bluetooth as it is far more unreliable than the RF modules and has shorter range).

Then I have written a Windows application in C# that controls all these devices and keeps current values for each device in memory that can be get and set by a web application (that my friend develops) over IP.

Currently I have temperature and humidity sensors and a 10W RGB LED that I can control remotely. Next thing will be an Arduino controlled relay that will fit inside a ceiling rose that allows me to switch the lamp on and off remotely.

This brings me to what I see as the biggest issue with this project... Power supplies. Since all these devices connect to 240V mains (I don't want to re-cable the whole house....), each of these devices needs its own little power supply. I'm using the smallest I could find (5V "USB chargers") but still, the PSU always takes up the most space in these devices and limits how small they can be made...
50  Development / Other Software Development / Re: Agentuino - A lightweight SNMP Agent on: March 01, 2012, 04:38:34 pm
Great. It's working .. ;-)

I just realised that we were discussing this in the Agentuino thread. I hope LAVco doesn't mind... ;-)
51  Development / Other Software Development / Re: Agentuino - A lightweight SNMP Agent on: March 01, 2012, 04:19:37 pm
I take it that means it's working? ;-) Or have you not tried yet?
52  Development / Other Software Development / Re: Agentuino - A lightweight SNMP Agent on: March 01, 2012, 04:04:23 pm
I think the problem is shown on the first screenshot. You only have GPRINT items in your graph template. These are text prints. You need to add an AREA item (filled graph). See the 2nd and 3rd (from bottom) of my screenshots...
53  Development / Other Software Development / Re: Agentuino - A lightweight SNMP Agent on: March 01, 2012, 10:32:04 am
Well, that's progress...
Not sure why the graphs don't show...

Can you please post a few screenshots of your cacti config? Specifically  a screenshot of the page shown on the 5th picture in my post (the one with all the screenshots). Then, on that same page click on the first item in the list on the top (should be the graph item) and post another screenshot of that page.
54  Using Arduino / Networking, Protocols, and Devices / Re: RF1100-232 serial to RF transceiver module on: February 29, 2012, 02:32:10 pm
OK, I've learned quite a bit more about these modules. For anyone who might be interested in future, I have created a page on my website where I'm collecting all the info I found about these modules. I've also made a little program that sends config commands to these modules. It can also be used to monitor communication. All that on the following page:
http://www.yesyes.info/index.php/electronics/rf1100-232-rf-433mhz-transceiver-module/
55  Development / Other Software Development / Re: Agentuino - A lightweight SNMP Agent on: February 29, 2012, 06:03:34 am
Silly me... I do have access to my network hard drive that has the backup of my sketches...
So here it is, the currently latest version of my weather station sketch.
56  Development / Other Software Development / Re: Agentuino - A lightweight SNMP Agent on: February 29, 2012, 04:53:59 am
OK, here is how I configured this in Cacti. It's been a while, so I hope I haven't forgotten anything.

First create a host/device for the weather station:

Most important here is the SNMP time-out and max OIDs per request. The defaults did NOT work for me. I had to increase the timeout to 1500 (1.5sec) because the Arduino takes quite a while to reply (roughly one second in my case). It also only supports one OID per request, so enter 1 in that field.

Then you need to configure one data source per value. Here is an example:

Select the host you just created and then enter the OID for that specific value.

Then you need a graph template. You can use an existing one to start with and modify it (or leave as is for the beginning)


I have also created a CDEF entry that divides all received data by 100. That is because I'm sending the temperature values from the weather station in 100th of a degree. So a returned value of 1 means 0.01 degree. That is because SNMP only knows integer numbers.
Here is the CDEF I added:


The CDEF is then applied to every item in the graph template:


Clicking on each of the items will show this screen:


Then it's time to create the actual graph:

Here everything comes together. Select the graph template that you created/want to use, select the host and then the data source.

OK, that's it. You should now get some graphs. Cacti only sends SNMP requests every 5 minutes. So give it some time to collect some data. Graphs will not appear until at least one value has been recorded.

I hope that helps a little. Just ask if you have any questions....

I will post the sketch when I get home. I have no access to that file here at work.. smiley-wink

57  Development / Other Software Development / Re: Agentuino - A lightweight SNMP Agent on: February 29, 2012, 04:09:07 am
I think Agentuino does not support SNMP Walk. There simply isn't enough memory for that in an Arduino. So you would need to know the OIDs and configure them manually in Cacti.

I'll see if I can take a few screenshots of how I configured graphs in Cacti. I'll also post my latest sketch as soon as I get home.
58  Using Arduino / Networking, Protocols, and Devices / Re: RF1100-232 serial to RF transceiver module on: February 27, 2012, 06:21:41 am
I've tried this again yesterday and, funny enough, it just worked. The modules now respond to the config commands. I have no idea what I've done differently this time.

I'm still interested if someone has used these modules before. I'd be surprised if noone has used them. They seem to be made for the Arduino world... ;-)
I still have a few things that are not quite clear and there doesn't seem to be much documentation around.

- what is the 16 bit Module ID used for? Can this be used to address a specific transceiver instead of sending everything to all transceivers on the same channel?

- do I need to build a mechanism into the protocol that avoids accidentally sending any of the config commands in the data stream?
59  Using Arduino / Networking, Protocols, and Devices / Re: RF1100-232 serial to RF transceiver module on: February 24, 2012, 08:09:03 pm
Oh, and this is the link to the command set that I found:
http://testdrive.kgts.ru/serge/RF1100-232.doc.html
I'm sending these commands as actual bytes, not as text. (I wrote a quick C# application to do that.)
60  Using Arduino / Networking, Protocols, and Devices / Re: RF1100-232 serial to RF transceiver module on: February 24, 2012, 07:55:27 pm
The item description is still there below all those "recommended items" ;-)

But here is the relisted module:
http://www.ebay.co.uk/itm/290672109935?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
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