Tag Archives: GSM Door Entry Systems

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.

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

New website new blog

To coincide with the latest firmware release for the Alpha GSM Relay Board and Auto-Dialer… now there’s a mouthful… we’ve redesigned the Advent Controls website and started a blog.  Yep this is the blog.  Well worth a read don’t you reckon?

Unfortunately we haven’t quite got the GSM Door Entry system on the market for launch of the website on 7/6/13 which is why it’s a blank page but it’s coming soon!  Don’t worry soon in electronics means days or weeks and not years like in bricks and mortar.

Hopefully we’ll have some interesting stuff to talk about on here shortly – even more interesting than this!