Thanks to Alec for sending in his Tiny TV project! Check out more on his blog here.
My boss brought me a gift from Mexico City a couple of years ago — thanks, Brian? Karen? Whoever it was? — and I’ve finally gotten around to doing something with it.
The key ingredients — the little TV chassis and an old i9000 Android phone — are things I already had kicking around, and were perfect matches for each other, so this project was just a matter of filling in the gaps.
I considered getting the fake buttons on the TV working but that idea wasn’t satisfying.
I hit on the idea of making an outlandishly large remote control for the tiny TV and this concept stuck. Main Electronics had a box of identical, shiny “new old stock” remote controls that it’s probably been warehousing for most of 30 years, so I picked up one of these for $2.00.
The big consideration was how to interface the remote control to the phone. I considered using USB OTG, WiFi, and/or writing some custom software on the phone, but in the end I googled the i9000’s Bluetooth support and found that it was decent, though old, and would happily accept a keyboard or mouse.
Further googling turned up AdaFruit’s BlueFruit product. They have a few variations and I was careful to choose the non-LE version because my phone doesn’t support it.
BlueFruit is great and very easy to use, but one thing it’s lacking is support for matrix (row/column) keypads. The remote control had one of these and I didn’t feel like rebuilding the keypad too, so this necessitated another microcontroller.
I’ve been having fun building things with bare-bones ATMega328 chips. This is the same chip as the Arduino uses, but pulled from the board and configured to use its own internal clock source. Building things this way results in an impossibly small parts list:
(Note: This is NOT the exact circuit I used — the remote keypad had a different row/column layout, but the concept is the same.)
That’s right, not a single component beyond the necessities. A keypad, a battery, the controller chip, and the BlueFruit board. The BlueFruit itself accepts a 3-16V power source and includes a 3V regulated output that’s usable for the ATMega328, permitting me to power it from the remote control’s stock 9V battery compartment.
Bluefruit EZ-Key – 12 Input Bluetooth HID Keyboard Controller – v1.2: Create your own wireless Bluetooth keyboard controller in an hour with the Bluefruit EZ-Key: it’s the fastest, easiest and bestest Bluetooth controller. We spent years learning how to develop our own custom Bluetooth firmware, and coupled with our own BT module hardware, we’ve created the most Maker-friendly wireless you can get! Read more.
Membrane 3×4 Matrix Keypad + extras – 3×4: Punch in your secret key into this numeric matrix keypad. This keypad has 12 buttons, arranged in a telephone-line 3×4 grid. It’s made of a thin, flexible membrane material with an adhesive backing (just remove the paper) so you can attach it to nearly anything. The keys are connected into a matrix, so you only need 7 microcontroller pins (3-columns and 4-rows) to scan through the pad. Check the tutorials tab for links to an Arduino library and example code. Read more.
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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 code.org, 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.