The Horoscope Computer by Mattel Electronics: Instructional Guide and Comparison

Previously I covered the Zodiac Astrology computer by Coleco. This product, created by multinational toy manufacturing company Mattel, is called the “Horoscope Computer” and came out the same year as Coleco’s Zodiac, 1979. The Horoscope Computer is both similar to and different than the Coleco computer. In this post, I’ll give a demonstration of Mattel’s Horoscope Computer and compare it with Coleco’s Zodiac at the end.

Via the Handheld computer museum:

The Horoscope Computer was released in 1979. It was designed to predict your horoscope and compatibility with others based on astrological predictions. An interesting note is that according to the instructions on the back, this game is only accurate from June 1, 1979, to December 31, 1987.

From the box:

Micro-computer “forecasts” your personal future or matches compatibility between 2 people.

How to use the Horoscope Computer

Find a PDF of the full instructions here.

The Horoscope Computer has two modes: Compatibility and Personal 

The three-way switch can be either off, in compatibility mode, or in personal mode.

How to use Personal mode:

Step 1: Move the switch to the P position.

Step 2: Enter today’s date or a given date in the future that you would like to ask a question about. The dates range from June 1st, 1979 to December 31st, 1987 so you can’t really use this device to get a reading for a current or future date. This is most likely due to the constraints of the electronics and memory capabilities at the time. I’ll pick today’s date (March 16) in 1982 (40 years ago)

Step 3: After you enter the date, it’s time to enter the sign of the asker. Since I’m asking for Adabot who was (allegedly) born on April 28th, I will reference the Sun Sign sheet and see that he is a Taurus. So I press the Taurus button.

Step 4: Ask a question! The question must be related to one of the 8 aspects 

  • Love
  • Career
  • Travel
  • Money
  • Friends
  • Spirit
  • Family
  • Creative

Adabot is curious about the state of his friendship with Blinka, so I’ll hit the friends button:

—— Fantastic ——

Now he’s curious about a potential love life with Blinka:

—— Friends —— 

It wasn’t meant to be!

Lastly, he’s curious about how he should use his money:

—— Save it ——

Compatibility Mode

In this mode, you can see how compatible you may be with anyone in your various life relationships.

Step 1: Enter today’s date or a future date

Step 2: Enter your sign, then the sign of the person you are checking for compatibility 

Step 3: Press the button for the aspect of life you would like to check for compatibility.

That’s it!

Here’s the patent for the Horoscope Computer from the USPTO if you’re curious:

Patent #D260,660

Comparisons between Mattel’s Horoscope Computer and Coleco’s Zodiac Astrology Computer 

Both Mattel’s Horoscope computer and Coleco’s Zodiac Astrology Computer were released in 1979 and while having a similar look and feel to the product, these computers had drastically different capabilities. The Coleco’s Zodiac was detailed, complex, and comprehensive, whereas Mattel’s was simple and intuitive but limited. Here are some similarities and differences between each of these computers:


  • Products have creative and circular form factors.
  • Products have music playing (basic piezo buzzers) as the horoscope is being calculated.
  • Products have advice modes about various aspects of life (called “houses” in Coleco’s manual).
  • Products give disclaimers about the astrological info that is given. Mattel’s manual states “FOR ENTERTAINMENT PURPOSES ONLY”. Coleco’s manual states “ASTROLOGY GUIDES — IT DOES NOT RULE!”
  • Products have an 8 character alphanumeric display.


  • Coleco’s Zodiac is a lot more complicated to use, includes a 100-page guide, and has 3 modes. Mattel’s is 12 pages, has 2 modes, and is much simpler to use.
  • Mattel’s computer has some wonky button pressing issues. I noticed it was hard to press a key on the computer without 2 or 3 of the same number being accidentally repeated. Coleco’s is easier to press buttons and I had no issues there.
  • Mattel’s computer is more geared towards assessing the various aspects of life for the user as well as compatibility with two people. Whereas Coleco’s is more geared towards a more complete horoscope and detailed astrological information.

It’s safe to say that Zodiac would be best for the astrology nerd to geek out on and pour through the manual, whereas the Horoscope computer would be best for someone without much astrology knowledge or as a great introduction to astrology.

These computers are super fun and it’s rare to see electronics like this nowadays. I say bring back the age astrology electronics!

Adafruit publishes a wide range of writing and video content, including interviews and reporting on the maker market and the wider technology world. Our standards page is intended as a guide to best practices that Adafruit uses, as well as an outline of the ethical standards Adafruit aspires to. While Adafruit is not an independent journalistic institution, Adafruit strives to be a fair, informative, and positive voice within the community – check it out here:

Join Adafruit on Mastodon

Adafruit is on Mastodon, join in!

Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.

Have an amazing project to share? The Electronics Show and Tell is every Wednesday at 7pm ET! To join, head over to YouTube and check out the show’s live chat – we’ll post the link there.

Join us every Wednesday night at 8pm ET for Ask an Engineer!

Join over 36,000+ makers on Adafruit’s Discord channels and be part of the community!

CircuitPython – The easiest way to program microcontrollers –

Maker Business — “Packaging” chips in the US

Wearables — Enclosures help fight body humidity in costumes

Electronics — Transformers: More than meets the eye!

Python for Microcontrollers — Python on Microcontrollers Newsletter: Silicon Labs introduces CircuitPython support, and more! #CircuitPython #Python #micropython @ThePSF @Raspberry_Pi

Adafruit IoT Monthly — Guardian Robot, Weather-wise Umbrella Stand, and more!

Microsoft MakeCode — MakeCode Thank You!

EYE on NPI — Maxim’s Himalaya uSLIC Step-Down Power Module #EyeOnNPI @maximintegrated @digikey

New Products – Adafruit Industries – Makers, hackers, artists, designers and engineers! — #NewProds 7/19/23 Feat. Adafruit Matrix Portal S3 CircuitPython Powered Internet Display!

Get the only spam-free daily newsletter about wearables, running a "maker business", electronic tips and more! Subscribe at !

No Comments

No comments yet.

Sorry, the comment form is closed at this time.