It’s during times like these that inspire innovation. I even made something for the cause!

 

In that spirit, the “Fighting Germs” contest is here to not only reward that innovation ─ but also give to other charities for those attempting the same thing! It’s fun, it’s beneficial.

 

They say the best time to plant a tree is thirty years ago. The next best time is today.

Version 3 of the hand wash timer. This time with sound!

 

Lights… yeah… that’s one way to show a timer (See V2 in this link). But, the tedium of hand washing has now prompted me to turn to sound.

 

The Micro:bit has some basic speech synthesis built-in, perfect for this situation. So, my goal this time was to have the Mico:bit count down the 20 seconds, or whatever amount.

For nostalgia's sake, the results turned out like those old text to speech sound-card programs from the DOS days.

 

  

How the system works:

Once again, when powered, the Micro:bit waits for the user input.

Pressing the “A” button will increase the time it counts down. So, when A is pressed you will hear an audible number.

 

Again, I don’t have a very sensitive button for this project. In my project, I ended up using a button I salvaged from a demolished factory. In my original plans would have been a contact switch with a travel almost nonexistent. However, my salvaged button travels about 2.54 cm (an inch). I give it a gusto press, and the sequence starts.

 

I added another function, a cancel button. Pressing “B” on the Micro:bit itself will cancel the sequence. Stops the countdown, in other words.

 

Only issue I had was the sound level from direct connection to the speaker. I know this could be remedied with using a powered speaker or amplifier. But, that’s an issue for a future version, I’m sure.

 

 

First, let’s gather all the necessary components you’ll need to build this project.

1x BBC Micro:bit

1x Kitronik Inventor’s Kit (This is mainly for the breakout adapter and project wires.)

1x Addressable LED panel

Project Wires Female - Male

1x Momentary Contact Button

1x Speaker

 

Video demonstration of the project:

 

STEP 1

Load the code onto the Micro:bit.

I am providing the hex file you need to drag and drop onto the Micro:bit, and the python code as two separate files. For the below process, just use the hex file.

Plug the MicroUSB cable into the Micro:bit, and plug the other end of the cable to a PC or MAC.

At this point, you are going to copy over the code to the Micro:bit. I am providing the program (code) in this post that needs to be copied over. When the Micro:bit plugs into a computer, it shows up as a USB flash drive. All you have to do is copy the file over to the Micro:bit, like it’s a USB Flash Drive, and the Micro:bit will reset, and the program is active.

You can remove the Micro:bit from the computer at this point. The program will start running, and without the rest of the circuit, it will not function.

 

A little bit about the code:

Yes, the countdown time only goes up to 30. However, do we need to wash hands for longer than that?

 

STEP 2

The schematic is the simplest I could make for a first version. Wire it up like the drawing.

 

STEP 3

Place the soap on the button!

 

 

STEP 4

When you turn the system on, it’ll start up immediately.

Press “A” to increase the time to whatever you want. I set it for 5 seconds to start.

Dispense soap, and the sequence will start.

 

Step 5 optional

Press “B” to stop the sequence at any time.

 

Conclusion:

Super-computer voice to the rescue!