input devices

Assignment

Group assignment:

• Probe an input device(s)'s analog levels and digital signals (As a minimum, you should demonstrate the use of a multimeter and an oscilloscope.)
• Document your work on the group work page and reflect on your individual page what you learned

Individual assignment:

• Measure something: add a sensor to a microcontroller board that you have designed and read it.

The Group Work

Link to our group page here

First we went and got the data sheet for an ESP development board that we had. Turns out is an old one.. but it should still work.

Lots of input choices.. this would be a great week if I could just get the board production a bit smoother.

The Individual Work

It's spring break, so we are still not able to get into the lab. So today, I am feverishly working to get my 3018 milling boards. I have been very active on the mattermost.

Genmitsu and Candle

Also, week 8 and week 9 merged a bit in my mind since I was doing so much with Electronics Production and the CNC machines. Here is a link to all of my chats with claude regarding the GENMITSU AND CANDLE regarding the Genmitsu in case I missed anything in my notes.

Mattermost Help

I have increased my trace width to 0.5mm in the kicad PCB editor. On mattermost, Adrián Torres Suggested these:

Ricardo Marques suggested I try easytrace5000

He also shared some documentation with me to help me learn to use it. As well as answering many questions while I learned how it works. The readme can be found here. Also can leave issue comments. Then he suggested that I go here to double check the gcode.

After looking at my pictures of my milled boards, Ricardo Marques suggested I try easytrace5000 felt that I have X axis backlash. I looked for screws to tighten, but we not succesful. He did also share this youtube, but time is not going to permit me to do this right now. Hoping it will mill good enough with wide traces.

Trace Tester Again...

Where to start , Where to start , Where to start ... I was working at home with Genmitsu, so I decided to try the line test there. I am using a Vcarve bit.

So I failed and failed at using the same line test that we did at the lab. In the end, I think that my set up just can't do that fine of a line or I don't have the correct bits.

Then I tried using easytrace5000. Ricardo has made a built in line test that goes to 0.3. This worked for me.

I was able to print a line tracer and see that bigger traces are better on my machine.

Easytrace5000

Using easytrace5000, I manufactured a board for my final project... hopefully and that will allow me to do the work for INPUTS and OUTPUTS week. This week, I will focus on getting the parts on that I will need for my inputs.

I wanted to document all the settings that I used for easytrace5000 so that I can find them again and so that others who are using a Genmitsu 3018 can also use them.

Step #1 - chose work flow type

Step #2 - bring in the file.

Step #3 Start adding your settings.

These settings are for a Genmitsu 3018 ProverV2. That is milling a PCB board using a 30 degree V carve bit.

Step # 4 Export your .nc file for use in Candle

Step #5 Do it again for cutting out your board

I ordered some bigger bits for being able to cut out the boards. They are 1/32, so it takes a while to do the cut out, but the size is good for mods or easy trace and PCB's. Doesn't waste a bunch of material.

Settings for my 1/32 cut out bits.. probably slower than needed. Remember, I am nervous Nelly.

Step #6 - Yay, way to go! NC viewer. What it looks like when you have it all ready to go.

Bring it into https://ncviewer.com/ for a quick looksie to make sure all looks good.

Remove the top lines of the code so that Candle won't be angry. You can do in candle or in notepad. If its Mods - remove the % from the first line. If its easytrace5000 remove:

(---)
(Operations (1):)
(  - isolation: LineTest.svg)
(---)

Genmitsu - Friends Again!

I brought the file into candle. Made a hieght map and milled away...

The trace milling of the new board on my Genmitsu.

Soldering on some Inputs

Inputs Testing

Note: Claude helped me reformat my findings and interpret them.

Photoresistor Measurement with Voltage Divider and Analog Discovery 2

This week's work involved a photoresistor (LDR) to explore analog signal measurement using two different methods: an Elegoo Uno (Arduino Uno compatible board) and the Analog Discovery 2 (AD2) used as an oscilloscope through WaveForms software. The data sheet is here.

Setup and Initial Resistance Measurement

Before observing the changing voltage signal, the resistance behavior of the photoresistor was first measured directly using a multimeter. The photoresistor was paired with a 5kΩ fixed resistor and the resistance of the photoresistor alone was measured under two conditions:

• Finger off (ambient light): 5.8kΩ
• Finger on (light blocked): ~10kΩ

This confirmed that the photoresistor's resistance increases as light decreases, establishing the expected behavior before the circuit was assembled and connected for voltage measurement.

To use the photoresistor as a voltage source rather than a pure resistance, the circuit was wired in a voltage divider configuration with a fixed 5kΩ resistor. The photoresistor was connected between 5V and the measurement point, with the fixed resistor running from that point to ground. This allowed the changing resistance of the photoresistor — which varies with light level — to produce a proportional voltage that could be read by the Analog to Digital Converter (ADC). I did this on a bread board first to make sure I had things working.

As an additional element, an LED was wired to switch on when the light reading crossed a set threshold value. The AD2 oscilloscope was used to monitor both signals simultaneously — Channel 1 displayed the analog voltage from the photoresistor voltage divider, while Channel 2 displayed the LED output. On the oscilloscope, Channel 2 appeared as an on/off style signal, sitting flat near 0V when the LED was off and jumping up when the threshold was crossed and the LED activated. This allowed the relationship between the continuous analog input and the threshold-triggered digital output to be observed visually in real time.

The sketch reads from an analog pin and outputs the raw digital value (0–1023) along with the corresponding voltage. Voltage = (ADC value / 1023.0) × 5.0. On the Elegoo Uno, the ADC has 10-bit resolution, which means it divides the voltage range (0V to 5V) into 1,024 steps (0 through 1023). So:

• 0V coming in → reads as 0
• 2.5V coming in → reads as about 511
• 5V coming in → reads as 1023

These numbers were displayed in real time in the Arduino IDE's Serial Monitor window, updating continuously as light conditions changed. When the sensor was covered, the values shifted noticeably, confirming the circuit was responding correctly to changes in light.

Voltage Readings

The AD2 voltmeter instrument in WaveForms was used to measure the voltage output of the voltage divider circuit under two conditions. With no obstruction, Channel 1 read 2.72V, reflecting the lower resistance of the photoresistor under the light, and Channel 2 read 2.72V, confirming the LED was active above the threshold. When a finger was placed over the sensor to block light, the voltage on Channel 1 dropped to 1.99V, confirming that the increased resistance shifted the voltage divider output downward, and Channel 2 dropped to essentially 0V (~-400 uV), indicating the LED had switched off as the reading fell below the threshold.

No finger (ambient light): - Channel 1: 2.72 V — photoresistor voltage divider output, sensor exposed to light, resistance is low, voltage is higher - Channel 2: 2.72 V — LED pin reading, light level was above the threshold and the LED was on

Finger on (light blocked):

Channel 1: 1.99 V — voltage dropped as expected when light was blocked, resistance increased

Channel 2: ~-400 uV (essentially 0V) — LED switched off because the reading fell below the threshold

Voltage drops when light is blocked. The LED threshold switching is visible on Channel 2 going from ~2.72V to essentially 0V.

Oscilloscope Readings The same voltage divider output was also connected to the Analog Discovery 2, with the 1+ probe placed at the measurement node and 1− at ground. The oscilloscope instrument in WaveForms displayed the signal as a live waveform, allowing the voltage changes to be seen graphically in real time. The Serial Monitor provided precise numeric values while the AD2 provided a visual representation of how the signal moved over time.

This oscilloscope capture shows both channels simultaneously as a hand moves over the photoresistor and then is removed. Here is what is visible:

Channel 1 (orange) — photoresistor voltage divider:

• Starts low (around 2V) while the sensor is in ambient light.
• As the hand approaches and blocks light, the voltage rises gradually in a smooth curve up to around 2.7V
• Holds steady at 2.7V while the hand remains over the sensor
• Drops sharply back down when the hand is removed at the far right

Channel 2 (blue) — LED output:

• Starts flat at 0V while light is unobstructed and below threshold
• Switches abruptly to around 2.7V the moment the threshold is crossed — a near-vertical jump Holds steady while the hand remains over the sensor
• Drops sharply back to 0V when the hand is removed

What this shows: - Channel 1 is a smooth analog signal — the voltage rises gradually as light changes - Channel 2 is a digital-style response — it snaps on and off at the threshold point - The slight delay between Channel 1 starting to rise and Channel 2 switching on shows the threshold moment visually

This is the board I made connected to the base of my final project that has has the photoresistor in it. I connected it with jumpers becuase I am going to mill a different board for the final project.

I was able to read the changing light readings the same as above with this board.