IT Tech Builds Own Doorphone

Via Reddit, this guy wanted to add access control to his telephone system, so he built his own doorphone out of a Rasberry Pi board and spare parts. Total cost: $45. I thought it was pretty cool.

Little off topic but the Raspberry Pi is a very handy micro-pc. I use them within our company to re-sell DDNS service to clients that dont have static IP or know about DDNS.

I am interested in your product
How can I get hold of you ?

If John is ok with it I will just share the parts and service I used to put the offering together. It isnt all that special but works well so far and can produce a little extra RMR.

David, that's fine.

Great, thank you. This is a bit long.

We originally offered this service through a company TZO which eventually got bought out and then basically disolved. There were a number a off the shelf NAT routers that had their software embedded and would work behind another NAT router which was key to this working. We would program an inexpensive NAT box to be exlusively a DDNS client and install it at the customers site. It was plug and play at that point and worked well for a couple years until TZO's demise. I searched for quite a while for another service and embedded device that would work behind an existing NAT router but came up empty. Then stumbled on the Raspberry Pi, saw that it ran a version of Linux and then found that the below NoIP offered a Linux update client and it all came together how I could recreate our offering and after testing found that this worked behind an existing NAT router. It has even worked behind a double NAT setup and reported the correct WAN address.

First we purchased a domain through This comes with their DDNS service and you can purchase more options as you need. Then I sourced Raspberry Pis, power adapters and a couple SD cards with their Raspbian version of Linux pre-loaded. I am no Lunix guru or even very good with it but have had exposure to it since the late 90's so I searched around and found guides on how to get an application to run at boot-up and installed the NoIP client on my Pi. Configuration was fairly easy and after some tests I was successful getting it to run at start without logging in to the Pi and it updated the NoIP service everytime. I then realized a problem with the design as the Pi uses an SD card for its operating system and this is prone to corruption on hard boots, power cycles etc. This would create issues in the field since we all get brown outs or power outages from time to time so this needed to be addressed. I then started looking for some type of UPS to use but didnt want anything large or too bulky as this is supposed to be a plug and play setup requiring an AC outlet and an ethernet port to plug into the customers network. A co-worker had recently purchased a battery pack for his phone from a company called Jackery. Ding, Ding, Ding perfect! I found my UPS. I bought their mid size one and after some testing settled on this as the solution. The pack is close to the size of the Pi in its case and my tests kept the Pi working for up to 6 hours on battery and when AC gets restored it starts charging up again.

Short break down.

- NoIP Domain and DDNS service - Low yearly fee and a bunch of sub-domains included

- Raspberry Pi w/power adapter, ethernet port, SD card with Raspbian OS

- Jackery or other cell phone battery charger (I havent tested others but sure they are out there)

Now on new clients I just log in to my NoIP account and create a new sub-domain for the client, put together a new Pi and Battery(I use double sided foam tape to attache the battery to the Pi), log into the Pi and update the NoIP client to update my new sub-domain(it automatically grabs the new sub-domain from NoIp and asks what domain you want to update) then restart the Pi and verify on that it grabed my IP. It is then ready to go to a client site and provide plug and play DDNS service for our clients.

NOTE: Clients network must be using DHCP.

NOTE: I purchase blank SD cards and xcopy my base installation to the blanks for new installs.

We charge our clients a monthly fee for this service and usually an upfront "setup fee" to cover the cost of the hardware.

For clients that dont understand networking, IP addresses etc this is magic. For those that do know it is just smoke and mirrors but it fits a need and as mentioned has created a little RMR for our company.