Cycling Safety Transponder, 15m - 45m Range

Started by Bret Cahill in sci.electronics.basics2 years ago 14 replies

The Bike Shield app never caught on because of spotty data in scenic areas. Also some cyclists don't like posting their GPS. A transponder is...

The Bike Shield app never caught on because of spotty data in scenic areas. Also some cyclists don't like posting their GPS. A transponder is the same thing as a bike light except it's at radio frequencies, works around curves day or night, and motor vehicles tune in to the frequency posted on the "Share the Road; Get Cyclist Alerts At AM 1090" sign. It would require a dedicated


OT electronics nostalgia, NYC subway system

Started by default in sci.electronics.basics5 years ago 2 replies

http://nycsubway.org/wiki/Power_Generation Wonderful site of the history, design, construction etc. of the NYC subway system. Vintage pix of...

http://nycsubway.org/wiki/Power_Generation Wonderful site of the history, design, construction etc. of the NYC subway system. Vintage pix of the 75 RPM Steam piston plants that supplied 25 Hz 11 KVAC to the substations and rotary converters and motor-generators that supplied 600 VDC to the 'third rail.' During the summers my buddy and I would plunk down seven cents, and get on the 242 n...


Relaxation Oscillator as a perfect example of regenerative feedback

Started by Patrick Chung in sci.electronics.basics7 years ago

Relaxation Oscillator circuit is a perfect example of regenerative feedbac= k that is special case of positive feedback. Simple and efficient,...

Relaxation Oscillator circuit is a perfect example of regenerative feedbac= k that is special case of positive feedback. Simple and efficient, this cir= cuit is practical for students labs and still applicable in the blinking tu= rn signal on motor vehicles, use in stroboscopes and as the time base in ea= rly oscilloscopes and television receivers. Read more: http://www.cirvirlab.com/in...


DC motor pwm, mosfet barbecue, etc.

Started by Anonymous in sci.electronics.basics9 years ago 12 replies

Hi, I built a pwm circuit (200 Hz switching frequency) using 12V as a supply, also using around 12V to the gate of an IRF530 mosfet. I tested...

Hi, I built a pwm circuit (200 Hz switching frequency) using 12V as a supply, also using around 12V to the gate of an IRF530 mosfet. I tested it with an automotive turn signal light (about 1 amp) and it worked just fine (without a heat sink on the mosfet). I then tried using it to control a 12V tire inflator/compressor (about 4 amps). The inflator operated fine, but then when I felt the mo...


Soldering 550m of copper wire

Started by Goran in sci.electronics.basics9 years ago 46 replies

I have to solder 550 - 600m of 1mm copper wire. Wire must be completely covered with solder. It will take some time to do this on regular...

I have to solder 550 - 600m of 1mm copper wire. Wire must be completely covered with solder. It will take some time to do this on regular basis ( with soldering iron ) so i was thinking to make some kind of slot in some aluminium housing and melt the lead alloy in it. Then i can put the wire in it and draw it slowly throe this slot. Additionally i can set some stepper motor on the othe...


Cycling Transponders and/or Safety Apps

Started by Bret Cahill in sci.electronics.basics5 years ago 4 replies

Bike Shield gives out the GPS of a cyclist or motor cyclist to safety minded motorists. A beep or something warns motorists when a cyclist is 20...

Bike Shield gives out the GPS of a cyclist or motor cyclist to safety minded motorists. A beep or something warns motorists when a cyclist is 20 meters around a blind curve on a "scenic" or "historical" highways. (Historic = no bike lane, no shoulder, no grading, no guard rails just a sheer cliff with blind curves on narrow lanes.) Alternatively, if privacy is an issue, motorists could be...


mosfet driver needed for logic-level mosfets?

Started by Anonymous in sci.electronics.basics5 years ago 43 replies

Hello, I've discovered logic-level mosfets, and am using an Arduino to drive a small 12VDC (about an amp or so) pump motor with PWM, using an...

Hello, I've discovered logic-level mosfets, and am using an Arduino to drive a small 12VDC (about an amp or so) pump motor with PWM, using an IRLZ34N as the power mosfet. Would a mosfet-driver be recommended to switch that mosfet on and off more quickly? Or is a logic-level mosfet already designed to efficiently turn on and off with the weak logic level signal? Thanks, Michael


how to get this PWM DC motor control to handle more power

Started by causalitist in sci.electronics.basics13 years ago 16 replies

this is the circuit in question, page 3 is the part I'm asking about, not the PWM circuit on page 1,2: http://kitsrus.com/pdf/k166.pdf The...

this is the circuit in question, page 3 is the part I'm asking about, not the PWM circuit on page 1,2: http://kitsrus.com/pdf/k166.pdf The IRF4905 and IRFZ44 limit current to 74A and 49A respectively. The LM324 Quad op-Amp limits Voltage to 32V What is an op-amp that will work here, but be able to handle 100v or maybe 55v min? As far as current and total wattage , I'm looking for min ...


All Ob A Sudden, Starter Motors Is So Small & Light You Can Carry 'em Home In A Filmy Shoppin Bag

Started by Bret Cahill in sci.electronics.basics2 years ago 5 replies

Summin didn't look right. The replacement starter motor was 2/3rds the dia of the original, mebbe haf the wait. I tink, WTF? Weren't all them...

Summin didn't look right. The replacement starter motor was 2/3rds the dia of the original, mebbe haf the wait. I tink, WTF? Weren't all them optimum nummers well settled back in the early Nicolacene? I toght, heck, no need to strap it onto the bike rack. I'll just stick hit into a shoppin bag. Affer an easy installation, the thang _akutually werked._! Affer about 2 days a theory he...


Electric Motor Cost/Watt Is Impervious To Size

Started by Bret Cahill in sci.electronics.basics5 years ago 4 replies

There doesn't seem to be much in the way of economies of scale when it comes to the cost/watt of electric motors. Most 50 kW motors cost...

There doesn't seem to be much in the way of economies of scale when it comes to the cost/watt of electric motors. Most 50 kW motors cost between 6 cents / watt and 20 cents / watt. Most 1 kW motors cost between 6 cents / watt and 20 cents / watt. Is this simply a matter of materials volume/ weight and therefore costs are linear with power? Bret Cahill


Anyone here know BLDC motors well? Hobby ones particularly?

Started by Anonymous in sci.electronics.basics4 years ago 5 replies

I want to use a hobby BLDC motor to power a compact high speed spindle to be used for engraving and the like. Mainly because they are so...

I want to use a hobby BLDC motor to power a compact high speed spindle to be used for engraving and the like. Mainly because they are so compact for the power and speed. I cannot find, for a price I can justify, a 24,000 to 40,000 RPM spindle that will fit in the space I want to put it. Looking at some hobby BLDC motors and then buying some to experiment with leads me to think that on...