Welcome to the N1IR Electronics Website. Totally off the cuff, one take, unrehearsed video projects for anyone interested in amateur radio, electronic design, makers, hardware hackers and science.


Get off your duff and build something!
Training the hand and mind since 1982.

Tuesday, June 4, 2019

Greetings Prospective Employer

Greetings Prospective Employer,

Please feel free to browse my page and projects, any question please contact me at 508-558-2559 or chrisjohnson2003@gmail.com


Click here to see my résumé


ELT/EPIRB Detector - Capstone Project

The design I came up with was a pager size device that would alert a pilot there ELT or Emergency Location Transmitter was on. When we got called out to search for these ELT's they were false alarms in fact over 59 out of 60 of my documented finds were false activation's. I wanted to design a product that a pilot could wear or throw in his fight bag that if there was a signal on 121.500 Mhz (121.775 prototype) and was less than 200 feet away it would beep.
 
Link below
Narrow Band Emergency Message System Interface
NBEMS is Narrow Band Emergency Message System. Think back to your last public service event, drill, or deployment. You probably passed a lot of traffic best suited for voice communications but...What if you had been asked to pass Roster of evacuees, Required prescription medications, Directions to a disaster scene. The needs of our Served Agencies have changed. They still need voice communications but...There's an increasing need for data communications. We need to be able to provide more than just voice communications from a ham with an HT
 
Link below
The Ignition Switch Delay for APRS node
"The Ignition Switch" featured in QST Aug09. This circuit provides protection against transient protection when starting your car and proves a delay off time for APRS equipment to send data before shut-down.
 
Link below

9th Grade Capstone Project Line Following Robot Project - Design of a ultra fast line following robot project for student engineering technology project. Worked in conjunction with Electronics Engineering, Drafting and Precision Machine Technology provided a “canned” project. Robot would follow a black line (electrical tape) on the floor autonomously, via infrared led and infrared photo transistor. The engineering student program an algorithm in the Arduino. Students assemble the electronics and build a custom machined chassis and wheels. Students would “tune” the program to different track conditions.

 
10th Grade Capstone Project“Blimpy”
Blue-tooth Controlled Blimp Project - Design of a ultra light modular control system for student engineering technology project. Worked in conjunction with Electronics Engineering, Drafting and Precision Machine Technology provided a “canned” project. Students assemble electronics and program the project, both in the Arduino IDE and a custom application on the cell phone using MIT APP inventor, scratch programming. Student would also design custom 3-d printed chassis in Solid Works

Online assembly instructions
http://www.n1ir.com/2016/01/engineering-academy-blimp-2016.html

Precision LUX Detector
Here is a design I made for a friend who wanted an white LED to turn on when it was dusk, but also wanted so adjustment via a pot. So off to pick a photocell, I picked a VT9ØN3 that was used in many low light applications. 

Once ordered we tested the photocell characteristic curve and found the following: 


Now the circuit we chose was a op-amp comparator type, this was a great circuit because we used a JFET input opamp the TL072 and current consumption was less than 1ma (our target current) and have a very crisp trigger level unlike using a single transistor or FET. We used a 25 turn precision pot to get the accuracy down to +/- 1 LUX at the set-point. In-fact a voltage of 1.625 at pin 3 (reference) was ideal for dusk at 7pm local, the photocell read about 130k ohms indoors at dusk shades open with 5.25 sqft total window area facing east+west (2.625 sqft ea) approximately 3 to 4 LUX
 

Bluetooth Controlled Blimp 2019

Were staring the kick off today with our 10 grade class with the bluetooth controlled blimp. below are some pictures and videos. Each student designs there own blimp structure and they learn the principals of flight.

The heart of the blimp is an Arduino ATMEGA328 on a custom designed board that I designed, along with the Blimp control APP you can find on the google play store, just search n1ir for the app. The app was designed with MIT APP Inventor and sends out a simple text string to control the motors and servos.

This year we got the weight down to 67 grams with the battery and can fly with just one helium filled balloon. This has been our best year yet, four years ago we started with four balloons, but with constant redesigns we trimmed the fat. We have also changed the material used in our Bi-Polymer Objet260 3-D printer to a lighter stronger materiel.



Rescue of a stuck blimp





Flying around before the competition



 3D printed chassis
 
 Solid Works, chassis design
Epilog Laser Cutter M2, cutting chassis paper on foam

 Team work!
Laser Cut Wood Chassis design


Tuesday, April 30, 2019

Greetings Scituate High School

 Greetings Scituate High School


Below is examples of our program

9th Grade Capstone Project
Line Following Robot Project - Design of a ultra fast line following robot project for student engineering technology project. Worked in conjunction with Electronics Engineering, Drafting and Precision Machine Technology provided a “canned” project. Robot would follow a black line (electrical tape) on the floor autonomously, via infrared led and infrared photo transistor. The engineering student program an algorithm in the Arduino. Students assemble the electronics and build a custom machined chassis and wheels. Students would “tune” the program to different track conditions.


10th Grade Capstone Project“Blimpy” Blue-tooth Controlled Blimp Project - Design of a ultra light modular control system for student engineering technology project. Worked in conjunction with Electronics Engineering, Drafting and Precision Machine Technology provided a “canned” project. Students assemble electronics and program the project, both in the Arduino IDE and a custom application on the cell phone using MIT APP inventor, scratch programming. Student would also design custom 3-d printed chassis in Solid Works
Online assembly instructions

TV-B-Gone
(Exploratory Project) – A universal remote control allows you to turn virtually any TV On or OFF. We prefer OFF. You control when you see TV, rather than what you see. The TV-B-Gone remote is so small that it easily fits in your pocket so that you have it handy whenever you need it, wherever you go: airports, restaurants, laundromats, etc. TV-B-Gone is a type of Universal Remote Control which works by shining pulses of invisible light that tells most any TV to turn OFF or On.

Online assembly instructions
 
http://www.n1ir.com/p/tv-b-gone.html

Exploratory Curriculumhttp://www.n1ir.com/p/exp2016.html
During our 5 day exploratory students build and take home ten unique projects. In an effort to reduce cost to the district I designed my own projects and documentation at a tenth of the cost of purchasing an off the shelf kit from a electronics supplier, Cost of my kits runs about $1.50 each.

        Resistor Triangle                       Resistor Square


        Resistor Cube                            Flashing LED


       Coin Decision Maker                Reaction Tester


        Insanity Alarm                          Continuity Tester



Example 11th Grade Curriculum Map

Related https://drive.google.com/open?id=0B4cPTBXMMjz9VjVmRjA2NkI0M3M

Shop https://drive.google.com/open?id=0B4cPTBXMMjz9VVBqQllodXZCS1U


Example Daily Lesson Plans

Related https://drive.google.com/open?id=0B4cPTBXMMjz9UTBsRU9oUlNieUE

Shop https://drive.google.com/open?id=0B4cPTBXMMjz9U1k5UlJRSjZuaDg


Please visit my You Tube Channel to see more projects and lessons
YOUTUBE Channel - https://www.youtube.com/user/chrisjohnson2003

Saturday, December 8, 2018

Student Made Video "How to Use Laser Cutter"

Very proud of my seniors, as an independent project they worked on a video for the shop to demonstrate How to Use Laser Cutter. This is a great instruction video and hope to see more. Thanks to TP,BD,PA and Bongo, you know who you are :)


Friday, December 7, 2018

555 Piano Organ Project

Hello, Here is a project that my sophomores are working on the 555 Piano Organ Project. It's a simple electronic toy piano can be easily constructed using the popular 555 timer IC. The NE555 timer IC was designed by Hans Camenzind in 1971. It consists of two threshold triggers, an RS flip-flop, and an output buffer. The 555 provides an easy, reliable way to create rectangular waveforms of adjustable pulse width and frequency by using different external component values.

Loudspeaker and Sound

A tone is a sound which is produced by a regular vibration. So it has only one frequency even though intensity/amplitude can vary. A Loudspeaker is an electronic transducer which converts electric signals to pressure variations to make the sensation of sound. To make this diaphragm of the loudspeaker will vibrate according to the frequency and amplitude of electric signals. Audible frequency range of humans is from 20Hz to 20KHz, so we are going to generate frequencies in this range using 555 timer and feed it to the loudspeaker.


Thursday, November 15, 2018

Students work on LCD TV

Hi just a posting were are fixing a 50 inch LCD TV. We found that the back-light LED was open, the left side of the LED strip behind the LCD had a bad LED. we tested the diver board and it was okay at 380 volts. The student learned how to troubleshoot high voltage power supplies safely, yes I did get a shock. Even with years of experience I get it once in a while, the important thing is keep one hand in your pocket while probing around high voltage, it can save your life.







Wednesday, November 7, 2018

Catastrophic failure of the FlashForge 3D Printer

Today we can across a Catastrophic failure of one of the FlashForge 3D Printers. The seniors (12th grade) students took it apart to find what the issues was. Unfortunately the head to the printer is beyond repair, another has been ordered and should be here in about one to two month. It was a great teaching point, we when over how plastic injectors worked and PID temperature controllers. We are going to make mechanical drawing in Solidworks and machine our own nozzles so we can have spares on hand.