Tag Archives: GSM Door Phone

Gold G2 GSM Intercom Door Entry Phone Update

January has proven to be a busy month with many trade and online orders for our ever popular GSM Auto Dialer system (GSM Dialer).  We’ve also taken on a new member of staff, Kelly, to handle orders for this product.  Hopefully for her sake the next couple of weeks will be a little quieter!  It would also allow further progress on our new Gold series of intercoms.

GSM for AndrewWe have been installing the first of our Gold Series GSM Door Phone Intercoms which is the Gold G2 Model.  However they are still in short supply and we’re still working on the firmware.

The early versions have been using the Capacitive Sensing Module on-board the PIC microcontroller.  This has proven highly reliable and accurate in the field however in theory this module is susceptible to electrical interference.

CSM Scope View

CSM Pad Trace

The CSM module generates a frequency dependent on the capacitance applied to the pin of the chip.  However it is possible for the touch pad to pick up high strength electrical noise and start oscillating at the frequency of the noise.  This would be seen as a press even though nobody touched it.  In practice we have not seen this but we also developed an alternative software based decoder which measures the voltage on the touch pad after it has been discharge and charged by the Analogue to Digital Convertor (ADC) sampling capacitor.

CVD Touch Pad Trace

CVD Touch Pad Trace

This technique of measuring the pad charge and then discharge into the same capacitor is known as a Capacitive Voltage Divider (CVD).  This method is very resilient to noise and electrical interference but does require more CPU processing time.  It is likely to be implemented across all of our Gold GSM Intercoms and will soon be behind the touch pads of our G2 unit.  When we have a full keypad version of the intercom available it will be important to use this technique hence it is being developed now.

Is the GSM Door Phone Entry Intercom System Suitable for Outdoor Use?

In the video we test the Advent Controls GSM 1-Button Door Entry system’s waterproof credentials.  Although officially rated as IP45 the unit is fully waterproof to falling rain despite the carefully designed holes for the microphone, speaker and wiring.

Can the Advent Controls GSM Intercom stand up to the ice bucket challenge?  Can it take a good hosing down?  Should JB find a new job as a fireman or stick to packing boxes?  All is revealed.

A donation was made to the charity RoadPeace

vlcsnap-2014-09-01-12h12m04s247The GSM Door Entry Intercom is available from our website on the following link:


GSM Gate Intercom Animation

I don’t know who did this but ‘Nigel’ has the right idea (although he should have used one of ours – ours is an all in one unit!).  I like it!


Save yourself time and money and buy an Advent Control One-Piece GSM Door Entry Intercom from here http://www.adventcontrols.co.uk/gsm-door-entry.html