Ring a phone and create a wireless doorbell with an Arduino.
Once upon a time my girlfriend found an interesting looking old phone for sale in one of those fancy French boutique-type catalogs. Their description:
?Not a reproduction, but a 1940's Swedish-made Ericsson bakelite original. Fully restored, with new wiring and microphone, nickel-plated rotary dial and authentic ring. Refurbished in Argentina.?
A brief background: Bakelite was the precursor to plastic, and was used to make a large percentage of phones and radios in the first half of the 20th century. This model (Ericsson DE 200) was actually from the mid-30?s, but whatever, I?m just a detail snob. They?re incredibly hard to find, and information about them on the internet is scarce.
Back to the story. I?m a sucker for cool looking antiques that are functional and still useful, so I was intrigued. Companies don?t put the same aesthetic design effort or build quality into their products these days, which is part of the reason why I like antiques. And who doesn?t like that hearty, crisp, old-timey sound of an actual bell ringing in a phone? Not this red blooded American, I?ll tell you that. I was just about to buy it when I saw the price. $395! Highway robbery!
Being the Do It Yourselfer and cheap bastard that I am, I headed to eBay to find one I could restore myself. Lucky for me someone was selling one and I picked it up for $10. I?ve only seen one other on eBay in the year since then, at it went for a lot more. I?ve seen websites that deal in antiques with a few for sale, typically for over $150. Suckers.
Seeing as how we didn?t have a landline anymore I had to come up with something useful for this phone to do. Our current doorbell is one of those cheap electronic ones with the boring ?ding-dong? sound, so modern and homogenous. Thus, the new life for this phone was decided. It would have to be wireless because I?m a renter and can?t permanently alter the house, and the current doorbell button wasn?t in a location where I could easily run new wire. The only other requirements were that the new button would have to look cool in a retro way, and the phone would have to be mounted non-permanently on a wall or other vertical surface.
You could really use any phone for this project, so don?t worry if you can?t get or don?t want the same model as mine. If you do get an antique bakelite phone, here are some basic steps for restoration.
Clean your phone with a rag dampened in one of those environmentally friendly orange based cleaners. If the bakelite is heavily worn, cracked, or sun bleached, you?re out of luck. It?s pretty much impossible to restore bakelite in that condition. Trust me. If your bakelite is dull after cleaning, you might be able to get away with polishing it with black shoe polish. As a last resort some people paint it black (I see a red door), but antique snobs will have a coronary at the mere mention of this. I say if it?s your last resort and you?re not trying to resell the phone as ?mint condition?, go for it. Here?s a good site on bakelite restoration.
The painted numbers on my dial were chipping badly so I used a toothpick and some white Testors model paint to touch them up a little. The black paint on the dial was worn just enough to look good but not ratty so I left it the way it was. The chrome (or nickel) on the dial was tarnished so I cleaned it with some generic metal polish that was white and smelled like ammonia. Don?t rub too hard or you might take off the plating, exposing the yellow metal underneath.
In the the DE 200 there?s a giant capacitor (labeled ?condenser?) inside. Capacitors go bad over the years and need to be replaced, and mine was causing the phone to ring weakly. You can try to find an equivalent modern capacitor if you have a schematic for the phone, or go the route I did and just bypass it. Connect the two incoming wires from the wall directly to the coils on the ringer by either soldering them or using alligator clips. I replaced the wall cord with a newer and longer one, nothing special, just disconnect the old one, strip the end of the new one, and screw in the wires where the old ones were. One of the plungers (the metal posts that pop up from under the handset when you pick it up) was missing so I found a metal collar and rivet at my local hardware store and improvised a fairly close replacement. You can see them sitting on top of the cabinet in the picture below.
As long as the ringer works you can ignore any other electrical problems with the phone, we don?t need to use the dial or handset. It?s possible that in a future version of this project we would want to use them because the phone interface board (more on that later) has the capability, but for now we?re keeping it simple.
Restore the phone
Open the Arduino sketch and upload it to your board. The sketch is here. The Arduino environment is here if you don?t already have it.
Program the Arduino
As I mentioned a while back, if you?re able to fit all the receiver electronics inside the phone it will need to be mounted near a power outlet. If you put the electronics in an external box the box will need to be near a power outlet, while the phone can then be anywhere within reach of a phone cord connecting the two. If you have an ugly box you?ll want a location out of the way so you can hide it in a cabinet or behind something.
Owen Morgan writes:
?I have good luck restoring Bakelite using the methods on the following website: http://web.ukonline.co.uk/freshwater/bakelit1.htm
Paste wax has been a winner for me, it is fairly gentle and doesn?t contain any harsh chemicals.?
Thanks to everyone who wrote in with their compliments!
Do you like this project or have suggestions on how to make it better? Do you want me to build one for you? Do you need tutoring on Arduinos, programming, and basic electronics?
Email me: btz at bryan zimmer dot net.
If you?re using a wall phone and you?re a renter like me, you need to get creative. Your landlord probably won?t appreciate you drilling holes in her walls so you can mount the phone like a normal human being. Instead, try mounting it on the side of some shelves, cabinet, or other vertical surface you own. You could get some strong velcro with a glue backing from your local hardware store and mount the phone to the cabinet. The only problem is that if you get tired of the phone you?ll probably have trouble removing the velcro from the cabinet thanks to the glue.
I got lucky and found that my cabinet was held together with bolts going from the top down into the sides. I loosened one so that it stuck up about 1/4 inch from the surface and threaded a zip tie around it and through the mounting holes in the phone. Sure, it?s not the prettiest or most elegant way of doing it, but it works and you don?t really notice it unless you?re right up next to it. In this picture you?ll see how the phone is mounted, plus the rivet and collar I mentioned earlier.
If you?re able to fit all the receiver electronics I mention later inside the phone it will need to be mounted near a power outlet. If you put the electronics in an external box, the box will need to be near a power outlet while the phone can then be anywhere within reach of a phone cord connecting the two. If you have an ugly box you?ll want a location out of the way so you can hide it in a cabinet or behind something
I'll believe corporations are persons when Texas executes one.: LBJ's Ghost