Virus Blinky

Freeform electronics thingy vaguely shaped like a SARS-CoV-2 virus blinking out the virus’s RNA sequence.

The main body consists of 0.6mm copper wire shaped into circles and soldered together. There’s a makeshift hinge on one side so the ball can be opened to change the battery and reprogram the MCU. See the schematic for the rest of the electronics. The power switch connects the positive terminal of the battery holder to the outer sphere, the anodes of all the LEDs are soldered on there. The cathode is connected via a resistor per colour and side to the microcontroller.

The main challenge with the assembly is holding the parts in place while soldering, a third hand and some little weights to put on things to hold them down are quite helpful. I started with the two half-spheres, then added the LEDs, then the resistors and finally the MCU and the connections to the other half.

The RNA sequence in sars-cov-2.fasta is from https://www.ncbi.nlm.nih.gov/nuccore/NC_045512. I encoded it into 2 bits per nucleotide (encode_genome.py) as the MCU has only 16kiB of flash.

Current draw is between 1-5mA depending on which color LEDs are active at the moment (the blue ones are a lot more efficient than the green ones), which should last over a day of continuous use on a CR2032 coin cell.

Components:

• ATtiny1614 MCU
• 47uF 1206 capacitor
• SMD slide switch
• CR2032 Coin cell holder
• 0.6mm copper wire (maybe 80cm at most)
• 7 x blue 3mm LED
• 5 x green 3mm LED
• 5 x yellow 3mm LED
• 5 x red 3mm LED
• 3 x 3.3kΩ through hole resistor
• 1 x 2.2kΩ through hole resistor
• 2 x 1.1kΩ through hole resistor
• 2 x 330Ω through hole resistor
• some 30AWG wire wrapping wire (used to connect the two halves together as it is more flexible than the resistor leads)