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Master_Scythe

Rapid Flasher relay

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So, you know how Indicators get faster when a bulb blows?

If I was to use a flasher relay, to draw a small current, does this mean i'd get a super fast 'switch'?

 

 

I'm trying to backyard-hack-together a fuel injector cleaning bench.

 

So far I have:

 

- a fuel pump.

- A fuel rail with a Pressure Regulator

- 4 Glass Jars

- a wooden frame.

 

I'll be using a computer power supply for a steady 12V for the pump, and using the 5V out to pulse the injectors (not using 12v because I'll be holding them open rather than pulsing, and, hot coils are bad).

So far I've spent a total of about $5 on some wood glue and a piece of pine :P

 

I'm just trying to get a way to pulse these rapidly on the super cheap.

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I don't think the flasher relay would even work with only 5V going through it. The faster speed would likely be due to less current drain so my guess would be that at best the thing would run slower than normal if only receiving 5V.

 

But here's a video of a bloke fixing a relay with dodgy contacts - the circuit is pretty simple so could probably be easily modified to operate properly on less voltage (forward to about 1:20 to get past irrelevant crap) -

 

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ah, right I see.

 

lower voltage would mean longer....

 

Any idea where to source a cheap rapid flash\ rapid switch relay?


I can always add a voltage regulator to the output, so I can trigger with 12V still.

 

If I find a modern flasher, it looks like it'll work.

http://www.instructables.com/id/Automotive-electronic-flasher-rate-modification./step2/Inside-the-Flasher/

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I suspect the solution you want might involve a circuit of passive components that can cope with high current.

 

Another thought I had was half-rectifier of the output from a low voltage AC source - thinking wall-warts as used by some appliances, 9V AC is pretty common.

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heyyyyyy now you're thinking!

 

9V is what I want too. Though AC is going to be 50\60hz. I was hoping more for like 6hz.

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I think easiest is going to be using an indicator flasher, with a modified resistor.

4 times a second would be enough; faster is just a bonus.

 

I can power it at 12v, and put a 9v regulator on the output.

 

Considering its going to be pulsed, 12v is probably totally safe, but I'd prefer to be over cautious than burn out an injector.

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NFI what the requirements are. I would guess it should be a piezo injector in most cases. They can be activated with very little power but I imagine they'd be somewhat like a solenoid in that more voltage and current = quicker and more positive action.

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and it needs more power too because the rear of the pintle is pressurised.

 

I'm thinking I gut a cheap $2 strobing LED flashlight.

 

Being an LED i'll get a DC current.

 

Use that DC flashing output at drive a REAL relay, 15A or so (horn relay, probably); and I'm good.


Or if I can be bothered, I have a spare Arduino mini floating around somewhere I could rope into 'relay trigger' duties.

 

I could even use the default LED "Flash" demo code to do it!

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I used to use a Light emitter relay circuit ,its all condensed in a single IC chip. One side of IC is for flashing circuit and opposite side is the receiver circuit. All you need is a 555 as a timing circuit. The IC can be found in the relay circuits section of most electronic dealers ,they use them in modern cars too.

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555 Timer IC pops to mind https://en.wikipedia.org/wiki/555_timer_IC

 

I guess so long as the current load isn't too big you can just use direct hookup.

Ry is on the money as usual. I wouldn't bother pissing about with jury rigging this, under volting that.

 

Use a 555 in a free-running configuration to drive the gate on a power MOSFET, which controls the relay coil's supply.

 

Here's an opportunity for you to learn some electronics fundamentals. :)

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Use a 555 in a free-running configuration to drive the gate on a power MOSFET, which controls the relay coil's supply.

 

Here's an opportunity for you to learn some electronics fundamentals. :)

 

Is there any need to use the relay then? With a sufficiently powerful Mosfet you could drive the injector from that.

Then you could vary the switching speed over a huge range. When I was in to RC model aircraft it's how the speed controllers worked and some of those motors where pulling huge amps.

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555 Timer IC pops to mind https://en.wikipedia.org/wiki/555_timer_IC

 

I guess so long as the current load isn't too big you can just use direct hookup.

Ry is on the money as usual. I wouldn't bother pissing about with jury rigging this, under volting that.

 

Use a 555 in a free-running configuration to drive the gate on a power MOSFET, which controls the relay coil's supply.

 

Here's an opportunity for you to learn some electronics fundamentals. :)

 

 

That sounds a lot more expensive, and harder than, say

http://www.ebay.com.au/itm/2-Pin-Speed-Adjustable-LED-Flasher-Relay-Motorcycle-Turn-Signal-Indicator-HC-/252306987474?hash=item3abeab19d2:g:HLIAAOSwv9hW17PC

that.....

 

Interesting, and I'd love to learn.... but..... that.... lol

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Go, go magic trimpot! (or trimcap)

 

Though you'd really not overly trust the things in a harsh environment, but would be great for your application.

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