## Monday, March 9, 2015

### Arduino Day 2 + Alibrijes

Today in 7th grade we had an electronics lab using the Arduino microprocessor. We have been exploring electronics, and students have been applying their maths with this forthcoming project.

Students thus far should have turned in:

1. Sketch of the top, front, and side of their Alibrije animal.
2. Sketch of the armature of their Alibrije animal. This sketch will also include where the battery compartment, LED's, and switch will be located.
3. A schematic of the circuit that will be used in their animal.
Students have been learning about Ohm's law: $$V= IR$$ We then solved for R or for resistance or Ω's.
$$R=/frac{V}{I}$$
We then modified this further so that we could solve for the proper resistor:
$$R=/frac{V_s - V_f}{I_LED}$$

For example:
$$V_s = 9$$
$$V_f = 2.3$$
$$I_LED = 20 mA$$ *This needs to be converted to amps (A).  $$/frac {20 mA}{1} * /frac {1 A}{1000mA}= .02 A$$
$$R=/frac{V_s - V_f}{I_LED}$$
$$R=/frac{9 - 2.3}{.02}= 106Ω$$

In class we discussed standard resistors and that a 106Ω resistor does not exist. If we wish to use a standard resistor we will have to use the next highest resistor which is a 150Ω's.

Which is a Brown Green Brown resistor.

We also discussed what it means if we use two LED's in our circuit.

Other class activities consisted of students finishing their basic Arduino Lesson one on Google Classroom, and Arduino Lesson two which was a group worksheet.

Finally some students worked on the beginnings of their armature!

It was a packed day!!!