From the archives: A talking gadget from the 1920s

To mark our 150th year, we’re revisiting the Popular Science stories (both hits and misses) that helped define scientific progress, understanding, and innovation—with an added hint of modern context. Explore the entire From the Archives series and check out all our anniversary coverage here.

Water level changes: float bobs, pulls cord, lifts tone-arm, moves needle, needle hovers over disk; caller calls, switch-operator connects, electric relay answers, soundbox lowers, phonograph spins, needle contacts disk, recorded voice announces numbers etched into precisely-positioned grooves. The result? A remote reading of the water level in a reservoir.

Rube Goldberg would be proud! 

Then again, when Popular Science published “Talking Machine Phones Height of Water in Reservoir” in November 1922, Rube Goldberg was just making a name for himself, and this contraption was a novel device on the forefront of telemetry—and a small window into a future sensor-filled world. Although the short piece doesn’t identify prospective customers, presumably water utilities would save time and cost calling the local reservoir for a water reading versus dispatching a technician. Or, perhaps an idle Vanderbilt or Rockefeller might find it amusing to keep a distant eye on the water levels of their country estate swimming pools.  

A century later, sensor networks have come a long way. Smart litter boxes, for example, monitor your furry feline’s output; canine lovers can check-in on their barking companions; ingestible sensors will tell you if pops took his meds; slip a snore-detector under your partner’s pillow to settle the snoring debate once and for all; save your nose by monitoring your infant’s bowel movements; save your nose twice by monitoring your own movements; take the guesswork out of grocery shopping with a fridge cam; a WiFi water sensor will sense leaks before they get out of hand; or, if they do, dispatch your robo-mop from the office.

“Talking machine phones height of water in reservoir” (November 1922)

By combining the telephone and phonograph, an English firm has perfected a novel device that automatically announces in either words or code signals the height of water in a distant pond or reservoir.

The recorder can be “run up” or switched into any existing telephone or telegraph circuit when information about the height of water is sought. As installed, the new device consists of a phonograph mechanism with a phone transmitter substituted for the sound box. An electric motor drives the record table, and a relay, acting through levers, stops and starts the machine and lifts the needle from the record.

Float controls recording needle

The recording disk contains 200 concentric grooves, each groove a vocal record of a certain height of the water. By the movement of a float that rests on the water, the tone arm, sound box, and recording needle are moved laterally into position with the disk in such a way as to give the correct reading when the needle is brought into contact with the disk.

To effect this contact, the sound box, with needle, is automatically lowered when the disk mechanism is in rotation, and raised again above the disk when the mechanism stops.

The instrument is connected in the usual way with the nearest telephone exchange, and is given a regular subscriber’s number. When the inquirer seeks information about the height of the water, he asks Central for this number. As soon as the instrument phone rings, the needle immediately drops to the record, which makes three revolutions, and a voice announces over the telephone line the exact height of the water. The short “speeches” on the record range from “empty” to “one, double nought,” enunciating each digit of a figure, such as “seven two” and “seven two half.” The mere ringing of the phone sets the mechanism in operation, delivers the spoken information, and closes the recorder.

In the code signal type of mechanism the grooves on the record contain various combinations of dots to represent the changing height of the water.

Some text has been edited to match contemporary standards and style.