HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
Blogs
Gadget Freak
Gadget Freak Case #220: Power Lock With a Secret Code
7/20/2012

< Previous   Image 2 of 2   

This project may be adaptable and scalable to be installed into an outlet box.
This project may be adaptable and scalable to be installed into an outlet box.

< Previous   Image 2 of 2   

Return to Article

View Comments: Newest First|Oldest First|Threaded View
<<  <  Page 2/2
mrdon
User Rank
Gold
Re: Keeping the kids safe
mrdon   7/21/2012 6:41:15 PM
NO RATINGS
Very cool and practical project. It's quite interesting to see ASM code being used eventhough C is language is common in todays embedded products. Now I have a real world example of ASM code to show my microprocessor class at ITT Tech.

armorris
User Rank
Platinum
Re: Power Lock power source
armorris   7/21/2012 10:07:20 AM
NO RATINGS

Thanks, William. I recently bought and reverse-engineered a smart outlet strip (i.e. master/slave power switch) to see how someone else solved the problems I had to solve. It used a more complex method to save standby power consumption. It used an opto-coupler and 4 diodes to switch in an extra high voltage capacitor when the relay is on to prevent burning up surplus power in the zener diode when the relay is off. BTW, the high voltage coupling capacitor provides about 20mA per microfarad of available current at 12V0VAC, 60Hz.

wgrill
User Rank
Iron
Power Lock power source
wgrill   7/20/2012 8:45:33 PM
NO RATINGS
I liked your design used in Gadget #195, much better than the one I have always used to derive appliction poiwer directly from teh line VAC. It provides a lot more flexibility in both available voltage and current. As for the code comments... comments can always be improved. I usually only comment on the major loop or function boundaries and when ever there is a user modifiable variable, table or other issue.    

Charles Murray
User Rank
Blogger
Re: Keeping the kids safe
Charles Murray   7/20/2012 6:35:00 PM
NO RATINGS
Yes, a great gadget done for a dirt cheap price. The only item of any expense is the prototype board ($12). Everything else is pennies.

armorris
User Rank
Platinum
Re: Keeping the kids safe
armorris   7/20/2012 5:54:58 PM
NO RATINGS
I responded too quickly. I see now that your ASM code does indeed have some comments in it. The code should be easy enough for someone skilled in the art to figure out, anyway.

Sorry about that! Great project!

armorris
User Rank
Platinum
Re: Keeping the kids safe
armorris   7/20/2012 5:29:38 PM
NO RATINGS
Wow! Thank you William, for using my SCR voltage regulator! I invented it back in 1978. I tried to publish it in EDN magazine back then and they didn't want it. It's loosely regulated, but it is very energy efficient. When the relay is off, you're not burning up power in a zener diode. You already know that you can add a small voltage regulator if you need more precise regulation, like for the microcontroller. You may have seen it used in three of my GF projects, GF#195, the master/slave switch, GF#198, the remote fan control and GF #218, the space heater thermostat. I have used it in a number of unpublished other gadgets that I have around the house as well. Maybe it was a good idea, after all, huh? I've had a couple of people ask me about it. At least one person appreciates it. It's also more robust against power surges than a zener diode regulator. The master/slave power switch and several other gadgets I have that use the SCR circuit have survived many thunderstorms here in Florida, including one that took out half the electronics in my house.

Yours is a great project! Some comments on your ASM code would have been nice, though.

Andrew R. Morris morr3763@bellsouth.net

Jack Rupert, PE
User Rank
Platinum
Re: Keeping the kids safe
Jack Rupert, PE   7/20/2012 3:53:50 PM
NO RATINGS
When I was young my dad used a low-tech version, although it was more of a general safety thing rather than to keep me out of it.  Basically, he wired the main outlets in the workshop through a switch mounted in a lockable box about 6' off the ground (although I dont' think the box was ever actually locked).  It box also had a red indicator bulb to remind him to shut off off workshop power when he was done.  This kept some of his older tools from being a potential hazard (fire or otherwise) when nobody was around.  Later, he upgraded the circuit to include a GFI when those things became common.

Rob Spiegel
User Rank
Blogger
Keeping the kids safe
Rob Spiegel   7/20/2012 2:21:50 PM
NO RATINGS
This is a great gadget for keeping the kids from playing with potentially dangerous tools. I would hope this is preventive safety and not locking the barn after the horse got out.

<<  <  Page 2/2
Partner Zone
More Blogs from Gadget Freak
Adam Berger hacked a computer keyboard into a mini key-tar to play with his band.
Dick Bipes couldn't find a boat lift remote with the specs he wanted, so he created his own for automatic operation.
This Gadget Freak Review looks at a keyless Bluetooth padlock that works with your smartphone, along with a system that tracks your sleep behavior and wakes you at the perfect time in your sleep cycle to avoid morning grogginess.
Colorado State University students have created “One Shot Two Shot, Red Shot Blue Shot” -- a Dr. Seuss themed target game where the objective is to get the most points with six shots from the gun.
This solar charge controller, which is placed between a solar panel and a battery, regulates the voltage and current coming from your solar panel. It is used to maintain proper charging voltage on the batteries.
Design News Webinar Series
9/10/2014 11:00 a.m. California / 2:00 p.m. New York
7/23/2014 11:00 a.m. California / 2:00 p.m. New York
7/17/2014 11:00 a.m. California / 2:00 p.m. New York
9/25/2014 11:00 a.m. California / 2:00 p.m. New York
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Sep 22 - 26, MCU Software Development – A Step-by-Step Guide (Using a Real Eval Board)
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Next Class: September 30 - October 2
Sponsored by Altera
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2014 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service