Course Administration and Procedures
Guidelines, Rules and Procedures
This is an overview of the system you are building for your first project. From day to day, you will be building each of the small components shown in the block diagram.
Four part series from http://www.circuitdesign.info/blog/2008/06/analog-vs-digital-part-1-introduction
Pinouts, circuit diagrams, and other visuals that are helpful throughout the thermochamber project.
Note: ONLY CUT USE THE BNC CABLES IN THE BACK OF THE ROOM THAT HAVE ALREADY BEEN CUT FOR THIS EXERCISE!
1. Convert a BNC to BNC cable to a BNC to breadboard connectors
2. Create a DB9 female cable with breadboard connector leds connected to pins 2, 3, and 5 with colors as followed; red on 2, blue on 3, and green on 5.
Test your cables for continuity and resistance.
Power Supply Excercise
Set the voltage on the right variable power supply to 12 volts. Repeat on the left variable power supply. Measure both using a volt meter. Run red and black lines from each of these sources. Connect the line from the black port of the right amp to the red port of the left amp. Now measure the voltage across the right port of the right amp to the black port of the left line. Presto---you now have +12,"ground" and -12Volts.
Select desired voltage drop and current of diode based on 1) desired light level (use LED spec sheet) and 2) power/voltage available from source (use sources spec sheet). You can fry both the LED and part of the source by making the desired current larger than the item allows.
2. Design a battery testing circuit that does not use a voltmeter (hint: idiot light). Look at the power point on lighting the LED with an Arduino for some additional help. Google it! there are some cool circuits out there. Constrain yourself to only items available in the lab
Grab a Mega and a Teensy for your use this semester.
We are not using this approach for this course.
If you are interested in learning about microcontrollers and coding in Assembly and C, this would be good to look into.
Experiment 1 - Look at Blinking LED on Scope
Experiment 2 - Connect Serial Cable From Back of Computer to Scope
In the DB9 drawer are cables that you can cutup. You might need to use a USB--DB9 converter to do the following. The purpose of the DB9 lab is to learn able terminal emulators (putty is an example), baud rates, ASCII codes and such. Look at all of the terminal programs options. After invoking utilize the DEVICE MANAGER to examine the serial adaptor configuration and then utilize the ascii code sheet and the scope to see the various binary codings. Go back into putty and set the Baud rate higher. Notice the smaller time width of signal. The standard BAUD rates people utilize start at a default of 9600 and go up and down by factors of 2---i.e. 4800, 2400, 1200 and 19200, 38400, 57600, 115200. Check these numbers out---see if you can get reliable serial communication at 1115200. Does your system need 1200 to work well?
Now that you have written a fair amount of code for Arduino your code might start looking a little messy. A good way to keep your code neat and clean is to go to >Tools at the top of the Arduino environment and select Auto-Format. This will improve the readability of your code by making sure everything is indented properly.
DO NOT OPEN THE WALL WART WITHOUT DISCONNECTING FROM POWER!!!
View the video here:
We don't want you to disassemble a power supply because it could be dangerous, but if you did decide to do it remember to unplug the supply and discharge the capacitors by touching the green and black wires on the large ATX connector! We have added some photos from when we did it.
On the other hand you might wish to convert a computer power supply to a lab supply. Here are what others have done.
PLEASE DO NOT TAKE APART ANY WORKING POWER SUPPLIES. WE HAVE PLENTY OF SCRAP ONES TO USE FOR THE CHAMBER.
ATX Power Supplies
specifications, testing and conversion to lab power supply
Switching power supply have non-constant voltage.
Computer Power supplies are usually switching.
Determine the switching frequency using an oscilloscope (assuming oscilloscope has small enough time scale)
Switching power supplies are not necessarily the same as regulated power supplies.
What are wall warts?
Very basic explanation of how ideal operational amplifiers work and can be used.
Be sure to do mostly everything in this Powerpoint. A common test frequency in the audio world is a 1000 Hz.
***USE A 270 KOHM RESISTOR IN PLACE OF A 2.7 KOHM RESISTOR ON REFLECTIVE SENSOR***
Improving Set Point with Interrupts
We can use interrupts to detect whether or not a button has been pressed instead of constantly polling for a change. Below is some code that you can copy and paste into your existing code.
You need to determine the proper resistance value if this LED portion of the sensor does not already contain a resistor.
For link that is broken in powerpoint on page 13 refer to the IR Tachometer document and specifically page 6.
Be sure to keep this circuit as you will use it later in your system.
Check the gain of the resistors in your circuit.
*****Circuit Diagram for monitoring fan speed can be found under Day 17******
******WHEN WIRING REFLECTIVE SENSOR USE 270 KOHM RESISTOR IN PLACE OF 2.7 KOHM*********
The fading tutorial is in File>Examples>Basic>Fade
Remember diode orientation matters.
Note that one board should be a large bread board and one should be a small one. The exterior board should be large as it will have to contain lots of wiring, buttons, and a display.
MW Fall 2014
Temperature sensor can be calibrated information is in pdf.
*Or with MATLAB. The goal is to visualize data collected by the Teensy/Arduino in pseudo-realtime
Project 1: selection criteria review and suggestions
Project 2: Selected project, requirements, constraints
After creating an account with Adafruit, you can access facilities on Adafruit.io to control IoT devices from the web and send data to the web. You should have the Arduino send data to the Huzzah via serial communication. This data is what the Huzzah sends over to Adafruit.io.
Find google's ip address by opening command prompt and typing: "ping google.com"
When someone gets it works, please update the sample Arduino code
Look at Getting to cPanel Instructions for login information.
In sample code anywhere you see 427access.com use ais.sites.lehigh.edu and for the site IP address replace 209,217,224,101 with 128.180.3.172 (the current IP address of the server). This address can be checked in cPanel on the left under "shared IP address"
Software
Additional Help on Task at hand
Hardware Manuals and User Guides
Learn how to could a microcontroller in C. Ideas work on all microcontrollers.
A tutorial for designing and simulating circuits in Altium.