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Recent Questions

August 2017

Laser Color Choice

I want to convert a 3D printer to a laser burning station to work with wood veneers and leather goods.

Any advice on the best type and color of laser to get? I’ve heard brown wood and leather reflect more red light and so I should use a blue laser.

Kyle Hoyos
Walkerton, IN

Oil Filled Caps

I’m trying to bring an old tube transmitter back to life. The power supply uses oil filled capacitors, which don't seem to have handy replacements. Assuming that I can change the oil to reduce the leakage current, what kind of oil is used?

Will motor oil work, for example?

William Helm
Eugene, OR

PCB Layout Software

I am a retired Field Service Engineer. Over a decade and a half after early retirement from IBM, a friend asked if an idea he had could be built. I assured him it could.

He offered me partnership if I would design and build a demonstration system. I designed, built, and programmed a system that works just like he wanted it to. An existing patent that I could find no work-around for expires this year. We'd like to have systems ready to go before we start doing demonstrations.

Now, I need to convert my proto-board to a more compact layout to be mass produced. The problem is that all the design software I've found requires that work be done online. Not even a simple schematic design without being on the Web.

I need recommendations for offline software to generate a file for use by a production service. All I'll need is a library of templates for basic TH mounting components. I do not intend to put the results out in the clouds because oftentimes when I look to the clouds, there be vultures about.

T. A. Rooks
Chelsea, AL

July 2017

Ransomware Scare

There has been quite a bit of news lately about so-called “ransomware.” Can someone explain how it works and is there a fool-proof way to keep my machines (and those of my family) protected?

Jerry Turner
Joliet, IL

Battery Killer

I have an older model Hunter SRC sprinkler controller that came with my house. Recently, the unit has been “resetting” to 12:00 am rather than keeping time. The unit has a nine volt battery that was reading 2.7V, so I replaced the battery. Within a week, the problem was back and the new battery was also dead (3.1V).

Any ideas what could be killing the batteries? I can’t find a schematic for this unit.

Norris Shaw
Santa Ana, CA

Laser Eye Protection

With high powered laser prices dropping like crazy, I decided to pick up a 3W blue laser from eBay for $50 to experiment with.

I’m concerned about eye damage and would like some advice on eye protection. What makes a pair of laser goggles good and what should I stay away from?

Gary Byrum
Milwaukee, WI

Salt Sensor

I have a water softener that needs pellet salt added to a brine tank. I’m trying to figure out a circuit to detect when I need to add salt as the tank is opaque and salt usage varies depending on use. The simpler the circuit, the better!

Salt Sensor
Greensboro, NC

June 2017

Miniature Parts Needed

I’ve been tearing down Seiko solar quartz watches in search of small efficient engines to power miniature robots. Can anyone recommend a source for additional components, such as miniature axles and wheels?

Naja Heilmann
Norcross, GA

What To Do With Leaded Solder?

I have a bunch of 2 lb rolls of leaded solder that I no longer plan to use, given the availability of lead-free solder. How should I dispose of the solder? Is it considered hazardous waste due to the lead?

Derek Raya
Derek Raya

Sequential Turn Signals

The simple way to do an automobile three-light sequential turn signal is to let the blinker turn on bulb #1 and then the circuit will do #2 and then #3; not a problem.

The problem is the brake lights that use the same filament in the bulbs. Hit the brakes so left and right will sequence once then stay lit, unless you hit the brake again.

Same with turning. One side sequences and if you hit the brake, the other side will sequence once and then stay lit while the turning direction is still sequencing. However, if you hit the brake, both sides will sequence once and then stay lit.

Proper function can be accomplished because aftermarket kits are available that do it correctly. Unfortunately, they are very expensive.

No matter what I think of, I cannot come up with any logic circuit that would prevent the brake indicator from sequencing once, i.e., blinker ON-OFF 12V, brake ON 12V; brakes only, ON 12V both sides.

Any simple ideas? Hope I do not need to program an IC. Guess I can always learn at 72 years old. Started reading N&V when it first began. Love it.

Daniel Zielinski
Port Saint Lucie, FL

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