applications and implications, May 23
This week  
Presentation applications and implications
video of the review (wildcard week)
video of the lecture
video of the recitation assistive technologies
Assignment Used software Files/Downloads/links
Propose a final project masterpiece that integrates the range of units covered,   Final Project

Final Project

Ok, ik have to describe my final project here. It changed a bit with what i wanted to do at first. But it became better :)

My final project is a Ice Thickness Measuring Device. At first i wanted it to be mobile (with wheels) and remote controlled, but that part i skipped halfway the fabacademy.

So what is it about?

[Dutch (toer)skating)( 

In the Netherlands, the Dutch skating is called Toerschaatsen, where skaters follow marked routes on frozen canals and lakes, which are coordinated by the Royal Netherlands Skating Union.

Despite its maritime climate in which real cold winters are rare, skating is traditionally the most popular winter pastime in the Netherlands even if many speed skating competitions have been moved indoors. Thousands of Dutch leap at the chance in cold winters to tie up their skates and glide across frozen lakes and canals, and sports stores all over the country sell out their skates.

Dutch skating tracks

The Netherlands is home of Elfstedentocht, a 200 km distance skating race of which the tracks leads through the 11 different cities in Friesland which is a northern province of the Netherlands.

Skate tracks on natural ice are maintained by the towns and communities, who take care of the safety of the tracks.

In my little town called Watergang, i’m one of the inhabitants that is responsible for the safety of the tracks of the waterland tourtocht, which was first organized in 1917, and was therefore the 2nd skating tour on natural ice after the elfstedentocht.

What i’m now gonna make as final project is still the ice thickness measuring device, but make it a bit more craft than high-tech product.

So what i want to do i’ll list here:

  • solenoid
  • electronics board
  • piezo
  • output, oled
  • housing
  • power distribution

What do i have to to:


I already 3d printed the spool. Hopefully today i will do the windings of the copperwire. And then test it off course. See the documentation.

So basically this solenoid is almost done

electronics board:

When the solenoid is ready, i will start testing with the solenoid, the piezos and the satshakits/atmega board i made during the networking week

If i get good measurements i have to redesign a atmega board for the actual Ice Thickness Measuring Device, breaking out only the pins that i need for this project.

And if it needs faster ADC, i have to develop a whole new board based on a xmega.


already tested knocking/hammering and measuring the impact with 2 piezo’s. I measured with the oscilloscope and saw the time difference. So besides the theory it also works in practice so far i could see. I have to do better measuring ones most components are ready.

For the piezo i have to mold and cast a block that fits in the housing. Have to make that soon.


for the oled i’m not concerned! I ordered 2 i2c oled displays and they will arrive today. I’ve had a lcd screen running a attiny85 and atmega boards, spi oled on the atmega board. SO as soon the boards are in, i’m going to set it up

But: i’m still thinking of outputting results in a different way. With led’s under the wood. It looks way nicer that a oled screen, less high tech and more beauty :) But then i also have to implement Bluetooth for the accurate measurements. And maybe this Bluetooth is a good idea anyway.

power distribution

I probably need 2 separate power supply’s:

  • 12V for the solenoid
  • 5V for the at(x)mega, oled and piezo’s

A relais is used to trigger/switch the solenoid. I ordered a Solid State Relais board - 1 channel 5V for this. I ordered this one because:

  • faster response . Faster on/off switching time than a traditional relais.
  • longer life cycle
  • no sound
  • better protected against vibrations and mechanical shocks
  • better suited for humid environments

I have to look into batteries: how do i get 2x power to supply the circuits, and if possible only 1 lipo charger to charge both circuits.


I am going to make the housing from wood from the old bridge at home that i replaced last year. It’s old solid hard wood. I already did some testing on the CNC for settings and also to look if i can use the wood, and it looks very good. For the finishing of the wood i will use propoleum, based on propolis, ethanol and linseed oil

[Propolis]( or bee glue is a resinous mixture that honey bees produce by mixing saliva and beeswax with exudate gathered from tree buds, sap flows, or other botanical sources. 

I can probably make it myself. I need a little propolis that i can take from my beehive, i have to distill ethanol from applewine that i made from apples of our garden and instead of using linseed i can produce walnut-oil from the tree in our garden. Walnut oil was one of the most important oils used by Renaissance painters. Its short drying time and lack of yellow tint make it a good oil paint base thinner and brush cleaner. The oil typically is combined with beeswax in a mixture of 1/3 oil to 2/3 beeswax.

But… it probably is gonna cost me a lot of time to make this from scratch. The finishing i have to do at the end. So when i have time, i will produce everything from scratch, otherwise i will cheat a bit with ingredients that i either made before or have in stock. But for the story i really like this finish.

Costs so far

  • SSR = 6,75 €
  • oled = 12,95 €

time management

From this time i have 3 weeks time to finish the project.

  • 1 day to finalize the documentation for all assignments
  • 1 day to finish the solenoid
  • 1 day to test the atmega with the piezo’s
  • 4 days to design and make xmega board
  • 1 day to connect and program oled and maybe the Bluetooth
  • 3 days program the xmega
  • 1 week to design and make the housing
    • wood
    • molding and casting for piezo elements
  • 1 day power distribution

So in total 16 days, so that fits in 3 weeks, but is a tight schedule ….