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Recent Questions

November/December 2018


PC Joystick Interfacing

Is it possible to connect a joystick to a microcontroller? PIC, PICAXE, etc. I don't want to have to take apart and hack the joystick. If so, what is required?

#11181
Nick Hulst
Cedar Rapids, IA


Logging Power Data

We have a Smart Meter installed for our home electric utility billing. Is there a way to read data from it to log usage data to a computer? I want to analyze my power usage by day of the week, time of day, devices and appliances in use, etc. Does the meter itself keep a log of this info that can be read or would I have to have a spreadsheet or other program to track it?

I'm not looking to interface any hardware to it. It would appear to have an RF link with the power company that might allow access. Any information about these meters would be helpful.

#11182
Lisa Miller
Cleburne, TX


Reflow Oven Opinions Needed

Anybody doing SMT reflow soldering at home? Trying to make the switch from TH to SMT. I was wondering what homebrew oven setups people are using and any tips and advice for a newbie.

#11183
Joey Dampier
Reston, VA


Audio Replay Device

Is there a device that will continuously "listen" to audio (via a mic or an earphone jack) and allow the user to push a button so that the device will repeat the last 20 seconds of what it just heard? I listen to scanners and ham radios, and often miss what was just said, and would like to get a repeat for clarity. I prefer a stand-alone device to an app or computer software.

#11184
John C
Montague, MI


Proximity Detector

I want to build a backup proximity detector like many newer cars have, as a fun, useful project. The type that beeps in reverse when something is behind my car; faster beeping means the object is closer. I'm new to electronics, and I need help designing the circuit. I thought of using the PING))) sensors available from Parallax to sense the distance to objects. Any help with the circuit is welcome. It would be preferred to have it auto-activate when in reverse, but I could just as easily flip a switch mounted next to the shifter to activate if it becomes too complex.

#11185
Gregory O'Rourke
Newark, NJ


Good Timing

I have an old model automotive timing light that attaches between the #1 spark plug and wire. How can I make an inductive pickup to sense the signal so I don't have to detatch the wire? Is it even worth trying to

#11186
Ricardo Stewart
Hanover, MD


About Resistors

Could someone explain what pull-up and pull-down resistors are, when and how they’re used, and how to calculate their values?

#11187
Andy Dietrich
Dallas, TX


Tuning The Music

Is there a way to vary the speed of a music CD player? I play my instruments along with the recordings and need to vary the pitch slightly to match the tuning of my instrument. We used to do this easily with vinyl by varying the speed of the turntable.

#11188
Klaus Herman
Raleigh, NC


September/October 2018


Scoping Out Some Advise

Certain techs and engineers still have a need to sample and view composite/NTSC video in its three axes form, that is: X axis (horizontal), Y axis (vertical), and Z axis (intensity).

In the past, this was accomplished using a CRT o’scope: horiz sweep to H input; vert sweep to V input; and video to Z, or intensity modulation input. Since CRT scopes are bulky, heavy, and, in most cases, not battery powered, a PC/digital scope with capture capability would be very handy for field use.

None of the scope ads I’ve seen list these features. Can anyone make some recommendations?

#9181
Paul Dendrenos
Barstow, CA


Resonator Frequency

I have in my junkbox what I believe to be ceramic resonators. What is the best way to test them to determine their frequency?

#9182
Donald Frazier
Geneva, IL


More Questions