Visonic car sensing?

Post by **Alexander** » Tue Aug 26, 2008 9:46 pm

Is this an idea? http://www.rfidplaza.com/pages/page.asp ... il&aid=854
documentation: http://www.axcessinc.com/products/docs/vehicletag.pdf

Or else (without the try of RFXcom receiver):
http://www.cheapertronics.com/product_d ... &item_id=7 in combination with http://www.cheapertronics.com/product_d ... &item_id=1

Post by **Sooty** » Thu Oct 23, 2008 12:15 pm

Thought I would add to this topic as I am thinking about a slightly connected project and wondered if anyone has any experience.

I have a motorhome that I want to add some extra security to.

There seems to be a whole load of cheap GSM auto dialler type alarm systems out there with wireless sensors although I suspect that cheap = poor. Anyone had any experience of these units?

At home I use Visonic 868MHz sensors with Homeseer and RFXCom plus the Visonic Powermax panel.

I already have one of these http://directions.ltd.uk/vehicle-tracki ... ing-vtu009 removed from a previous vehicle. I actually have the VTU008 model which has 2 inputs and 1 output. This unit is very good at what it does, but the software leaves a bit to be desired and there is no web-based tracking which is a bit of a let down. On the plus side it has very low power consumption in sleep mode, it has a geofence option with SMS notification, and the relay output can be controlled by SMS.

Whatever I choose to use must be 12 volt and have low power consumption because it will be left unattended for long periods. I do intend to use some sort of low-power notification to send an SMS when the vehicle battery falls below xx volts. The VTU sends an SMS if external power is lost, so perhaps I can use a circuit to disconnect the power if main battery voltage is below xx.

Ideally I would like to use Visonic 868MHz sensors for the system so when parked at home I can use Homeseer to monitor the vehicle. Also these sensors have good battery life.

I had thought about using a Visonic MCR-304 connected to the inputs of the VTU as the MCR-304 has very low power consumption. The problem with this approach is how to put the system into armed and disarmed states when away from home. I suppose I could use an externally mounted key operated switch to keep the VTU input circuit open when disarmed or use the VTU's output circuit to do a similar thing. That way would meen arming / disarming via SMS.

Ideally I would like a small, very low power 12 volt alarm panel with built in GSM and hard wired inputs for the MCT-304's outputs.

Any thoughts or experiences?

Thanks

Paul..

Post by **b_weijenberg** » Thu Oct 23, 2008 12:52 pm

Paul,

Is this an option: Connect the battery voltage using a voltage divider to the A/D input of a 40066 RFXSensor. The RFXSensor can directly be powered by the 12V.
The voltage divider can be 2 10k resistors.

Code: Select all

<font face="Courier New">                RFXSensor
---+12V-------- + battery conn.
         |
        | | 10k
        | |
         |______ A/D input
         |
        | | 10k
        | |
         |
---GND--------- - battery conn.
 </font id="Courier New">

I can modify the RFXSensor firmware so that it will xmit every 30 seconds or 1 minute only 1 packet.

Post by **Alexander** » Thu Oct 23, 2008 2:04 pm

Nice Bert. That is a good solution i guess for all the trouble we try to resolve with all kinds of products.

Post by **Sooty** » Thu Oct 23, 2008 3:19 pm

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Is this an option: Connect the battery voltage using a voltage divider to the A/D input of a 40066 RFXSensor. The RFXSensor can directly be powered by the 12V.
The voltage divider can be 2 10k resistors.<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

Thanks for the input Bert. Good (cheap) solution for monitoring battery voltage.

I know next to nothing about electronics. I can buy the resistors from my local electronics store.
From your diagram: do I insert one resistor in the + and one in the - lead from the battery 12 volts?

Will this make the voltage to the AD input 50% of the battery voltage, so if the battery voltage is 12.5 then the sensor will show 6.25?

I have a spare 40066 RFXSensor but as you say it would need to be modified because am I right in thinking that they only transmit if there is a temp change.

I already have 1 Visonic motion sensor in the vehicle and an MCT-100 connected to 2 sets of magnetic switches for the main doors and lockers. I can monitor this via the RFXCom plug-in when the vehicle is parked at home and I can just disable the sensors in the plug-in when I go away, but I need to have some way of monitoring when away.

Thanks again

Paul..

Post by **b_weijenberg** » Thu Oct 23, 2008 6:10 pm

Paul,

Send me the RFXSensor PCB and I will update the firmware and add the resistors. Open the RFXSensor by removing the 2 screws (under the label just above the battery compartment)

Or use this GPS tracker http://tariffman.co.uk/gpstrackers.aspx

Bert

Post by **Sooty** » Thu Oct 23, 2008 8:54 pm

Thanks for the offer Bert.

I think I need to give this project a little more thought. This is a new vehicle that I have only had for 2 weeks.

The vehicle is fitted with one of these http://www.victronenergy.co.uk/battery- ... s/bmv-600/ for the habitation batteries which I have discovered has a relay output that can be configured to operate if the voltage falls below a given level. I could connect that to an input of my existing tracker or another suitable GSM device or I suppose I could also connect a Visonic MCT-100 or MCT-302 in parallel to notify Homeseer if the low voltage relay has been activated.

There appears to be a number of alarm systems on the market that are targeted towards motorhomes and caravans. Some of these also have GSM built in. Perhaps I will research these a little further.

I was keen to use the Visonic sensors if possible as I already have the system in place to monitor these whilst parked at home but I suppose it won't be as easy as that.

Paul..

Post by **Sooty** » Sat Nov 01, 2008 7:35 pm

Well, today I finished the Motorhome alarm project. Thought I would post details just in case anyone finds it useful.

In the end I decided to use the low battery relay output from my Victron battery monitor and connect it to one channel of a Visonic MCT-100. Now I can see this device in Homeseer / RFXCom Plug-In and it will be triggered if the battery level drops below 50%.

For the alarm side of things, I decided to purchase a dedicated Motorhome alarm system which is very low power and integrates with the vehicle's central locking. Lock the doors with the keyfob and it is armed. This unit has an "alarm triggered" output which I have connected via a miniature 12 volt relay to the second MCT-100 channel and to the input of my GPS tracking device.

This seems to work well and uses only 15 mA from the battery when stationery and armed.

The only small problem I have now is that when the vehicle is moved away from home, I get a communication error in the RFXCom plug-in from the MCT-100 but I can live with that.

Paul..

Post by **TANE** » Sat Nov 01, 2008 10:26 pm

Maybe you can use a event to change the communication error in something car is not in the range

I have also MCT-100 maybe will also do that

Post by **Sooty** » Sat Nov 01, 2008 11:50 pm

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Maybe you can use a event to change the communication error in something car is not in the range<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

Yes. I think that is what I will need to do.

I have too many projects on going at present but I thought I should put the security ones at the top of the list.

Paul..