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 you duff and build something!
Training the hand and mind since 1982.

Friday, December 22, 2017

Project 12/15/17 50W x 50W Power Amp

The 50WX2 Stereo Power Amplifier. At 50 Watts per channel, the power amp kit costs less than the interconnects on many high end systems. Still, we find that many owners of $5,000+ systems use our kits for their second system. Why? To quote one student, “I put your amp up against my monoblocks…it wasn’t quite as good in some respects…but it was amazing how close it came. BTW, I had a blast putting the kit together!”

Why Build a Kit?

It's fun, relaxing, and educational. Completing a kit provides you with a great feeling of accomplishment, and we make complete kits that make it easy to build great sound. When you add your labor, you get high-end sound for a bargain price. The kits contain everything you need to build great looking, great sounding equipment. They have acclaimed assembly manuals with clear directions that produce first time success for 97% of the builders. Quick support makes the other 3% successful, too. We make great sounding, proven designs backed by knowledgeable support.

A special thanks to: 

Power Sources Unlimited, Inc. 
200 Stonewall Blvd., Ste, 4 Wrentham, MA  02093 

They are the company that donated the power supplies for this project.

 AMP and Power Supply

 Close up on PCB

AMP under dynamic testing

Thursday, December 21, 2017

Project Camping Candle

This project was designed and built by one of my seniors, we wanted to make a fake candle using LED's.

We came up with two LM555 astable multivibrator oscillators at two different frequencies and diode OR'ing the outputs to an blue LED, these two frequencies would beat together and cause the flickering effect you see on the video below. The student designed the circuit in GEDA and made a PCB using Protel to the T-Tech 5000 PCB Milling Machine.

This proved our rapid design process, the whole circuit form conception to working product was done in under 6 hours.

 PCB one of a kind proto type

Candle in action

Project 12/21/17 Digital Dice

Here is a project that my seniors are working on, Digital Dice. We used a 74LS193 Counter and a 74LS47 Decoder and a 74LS00 NAND Gate.

How it works. The counter counts from 1-6 and displays the count on the 7 segment display. So the first count starts at 0 and goes to 1,2,3,4,5,6 at count 7 the counter resets back to a pre-set condition of 1 then counts 2,3,4,5,6 on 7 resets back to the preset of 1 then counts 2,3,4,5,6 rinse cycle and repeat.

 Schematic on white board, Students will redraw this in GEDA and design a PCB in Protel

 Breadboard and testing

Here it is working

Wednesday, December 20, 2017

HVAC Repair

Here is a repair done by one of my 12th grade students, a Pipe Temperature Gauge. This was brought in non-working condition, we took it apart found some corrosion on the membrane switches on the PCB preventing the unit to turn on, cleaned and works great now. 

Here is the description on the company web site:

The Cooper-Atkins Model 4005i will measure pipe temperatures quickly and easily without a lot of equipment utilizing a claw type pipe clamp probe. Temperature registration is shown on a built-in digital LCD display. This unique instrument also allows measurements of liquids and solids with its retractable general-purpose probe hidden in the handle. Features include auto shut-off after 5 minutes of non-use, hold, max and min. The temperature range of this instrument is -20 ° to 300 °F (-29 ° to 149 °C). The Cooper model 4005i comes standard with a soft carry case including a belt loop so you can easily keep the instrument with you at all times.
It's the perfect tool to measure pipe surface temperatures and/or take measurements of liquids/solids quickly and easily without a lot of equipment with the same instrument. Patented Design. Can be used on pipes with diameters of 1/4" to 1-3/8". It features a cordless pipe clamp with a 2.5" retractable general purpose puncture probe. It includes a Nylon belt pouch.

Friday, December 15, 2017

Custom FM/MP3 Radio

Here is a project that one of my juniors did. He combined two kits and some speakers from a recycled TV to make a custom FM/MP3 Radio. Next week we plan on making a case with the Epilog Laser Cutter.

Here are the spec on the radio
1. With bluetooth audio receiver module, when cell phone and bluetooth module matching connection,the MP3 or nondestructive APE files via bluetooth sent to the product of the bluetooth receiver module to play,which has greatly helped the function of the product and entertainment.This product also be like ordinary MP3 decoder board,play U disk or TF card MP3 files,as well as the radio broadcast.(This product without bluetooth calling function,with no power amplifier,only connect to an external amplifier can it use)
2. Support signal switch directly.Support USB, TF
3. Support bluetooth (Bluetooth3.0 EDR) (after been paired with mobile phones can realize wireless music play)
4. Support USB/TF/Bluetooth/FM/LINE switch.MP3/WMA,WAV lossless music decoding chip.
5. Support USB/TF card switch,PREV,NEXT,fast forward,fast rewind,volume,EQ,play/pause,stop,single repeat,mute, shutdown and direct election.
6. Support Bluetooth PREV,NEXT,volume,EQ,play/pause,mute,turn it off.
7. Support FAT16,FAT32 file system.Support for MP1 Layer3,MP2 Layer3,MP3 Layer3 version of the song.Support 32-320 KBPS MP3 songs.
8. Support power off memory function: memory play songs and volume before power off.

Here are some links to the kits used:

Remote Control USB SD FM MP3 Player Module Bluetooth Audio Receiver Module

Sure Electronics AA-AK32111 Two Class AB Headphone Amplifiers 2x1W Kit

Tuesday, December 5, 2017

Project 12/8/17 Cable Tester

This weeks project for the sophomore class in shop is a CAT 5 Cable tester.

A cable tester is a device that is used to test the strength and connectivity of a particular type of cable or other wired assemblies. There are a number of different types of cable testers, each able to test a specific type of cable or wire. This one can be used for CAT 5, coaxial or any cable that has two conductors or more

The student breadboard and test the circuit our then mill out the PCB using a T-Tech 5000 PCB mill.

Project PCB and enclosure

Below is an example PCB CAD Design of the board

Friday, December 1, 2017

Project 12/1/17 Clock

Digital clock project, this is the same on featured at  


We made 8 clocks, students learned how to breadboard, mill a PCB and how to burn a ATMEGA328 using AVRDUDE.