Introduction: Vintage Toothbrush Timer
Step 1: Circuit Design
The circuit is designed around a wight sensor. I got one from a used digital scales. It is a pretty basic device: there are four wires: one is input current, one is ground and voltage difference between the other two wires is determined by a weight of an object on the scales. The difference, however, is really small, so one needs to use an amplifier to be able to tell that the weight has changed.
Here are components that I chose:
ATMega328p with 16Mhz crystal – I chose this micro-controller because it is extremely easy to use. There is also a good community support, as ATMega328p is used in one of Arduinos.
Ina12P amplifier – this device is created specifically for amplification of sensors' signals. It is not hard to use it. The only thing that I found tricky is figuring out the right resistance value for amplification gain.
TPS2020 switch – this is a great switch with a very low standby current ( <10 μA). I use it to control power of the servo that chimes.
MAX1555 charger – this device controls charging of device's lithium-ion battery.
2N3904 transistors – used to control lamps' power.
Lamps – I chose incandescent lamps out of esthetic reasons. Since I wanted to give the project a "vintage" look LED lamps did not quite fit the design. Although these lamps consume more power the feeling they evoke is quite worth it.
This device is able to work 3 weeks on a single charge.
Full schematic could be found on Github.
Step 2: Printing the Circuit
I used photo-resistive method to etch the circuit.
Step 3: Programming
There program is pretty strait-forward. Source code could be found on GitHub.
Step 4: Enclosure Design
Step 5: Putting Everything Together
Once the enclosure was ready I have put the circuit inside and connected all wires. Photographs attached to this step show how it all fits inside.
I would be happy to answer any questions and hear any comments about this project.
I also hope this device will inspire you to create some creasy contraptions of your own!
17 Comments
10 years ago on Introduction
I L-O-V-E the copper cups!! They would make great velocity stacks in my motorcycle.
Great instructable! Very elegant!
Jesse M.
10 years ago on Introduction
Just to say the cups are in copper, not brass (unless color changing due to the camera). Brass is a copper ALLOY (with zinc) and is yellow. My father is a coppersmith, by the way.
But most important: GREAT idea, definitely FAVE for me !!
(I made one with white diffused leds in a vitamin tube, but yours is better for sure)
Reply 10 years ago on Introduction
You are quite right: the cups are copper, not brass. The dish seems to be brass indeed. My bad.
It really shows after first month of use: the metals change their colors differently because of stains of water and tooth paste. I don't rush to clean it though: I think it adds to the character of the contraption.
10 years ago on Introduction
I went a much simpler route to time my teeth-brushing - I have a hourglass-tyupe egg timeer, which lives on the sehlf above my bathroom sink. I turn it when I start brushing and carry on till I notice that the sand's all run out
10 years ago on Introduction
After reading this I decided that it may look like English but this is obviously a lot more complicated of a language with smarter people speaking it
Reply 10 years ago on Introduction
Hm... Not entirely sure if I read sarcasm. If so, you are absolutely right â English is my second language indeed.
Reply 10 years ago on Introduction
Sarcasm definitely you wrote great I just don't speak electronics
10 years ago on Introduction
i have no idea what i'd do with this but it's very cool... i was thinking you could adapt it for an egg timer, (with little egg cups instead of toothbrush cups) etc etc, excellent for those of us losing our marbles and can't recall what we were doing a minute ago! :)
Reply 10 years ago on Introduction
I'd say it would work well to detect the loss of marbles. Of course at that stage we might not be able to understand what the blinking light counter means. ;-)
Reply 10 years ago on Introduction
Man it took me a minute already to work ou what you were talking about! I'd better get started making my marble counter or whatever it was I was planning to make before its too late :D Cheerio
10 years ago on Introduction
Very cool and nicely built! Is the weight sensor fixed calibrated or do you have a push-button calibration for when additional toothbrushes are placed in the brass cups? I.e. holding button down for >= 3 sec updates weight calibration offset with new present weight.
Again, great job!
Reply 10 years ago on Introduction
I thought that adding calibration button would make too complex of an interface. Weight readings are relative: if last time I read x1, I read x2 new and (x1 - x2) > E a toothbrush has been removed.
10 years ago on Introduction
Great job. I use my electric OralB which has a built in timer. This thing takes up a lot of space.
10 years ago on Introduction
Congratulations!
You've made Hack-A-Day!
Here is the article.
10 years ago on Introduction
I love it, even though it is missing an Android :D
Keep up the great work!
10 years ago on Introduction
Now that is the definition of "cool"...
5 stars everyone!
10 years ago on Introduction
Wow - that's so pretty. Great idea. :D