Build it yourself EOT device.


C

ChevelleSSguy

Member
Would anyone happened to know where to get the circuit board like what is being used for the FRED this guy built himself. Its not quite as nice as a Ring Engineering unit but its not 40-50 dollars either.

http://www.youtube.com/watch?v=bLQnl0QyLMQ

The only place I know of is through Ngineering. It would be nice to find a source for this flasher outside of the hobby though. Im thinking something along the line of a flashing advertising or novelty pin for a shirt or something.

(For instance, years ago I once saw an employee in a liquor store wearing a Rolling Rock shirt pin that had the familiar Rolling Rock bottle and one single flashing LED light on it. Sort of an advertising thing) They were giving away the pins so I grabbed one and its been sitting in the drawer ever since. Clearly has a small circuit board with the LED attached right to it and glued to a hole in the bottle.
 
Fry's has a flashing LED circuit board for $2.99.

A Google search will turn up a few more boards and a whole lot of do-it-yourself circuits you can buiild for a few dollars. One of the first projects I ever did with an IC was to make a flashing LED circuit using a 555 timer chip. That was about 35 years ago!

- Jeff
 
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jdetray said:
Fry's has a flashing LED circuit board for $2.99.

A Google search will turn up a few more boards and a whole lot of do-it-yourself circuits you can buiild for a few dollars. One of the first projects I ever did with an IC was to make a flashing LED circuit using a 555 timer chip. That was about 35 years ago!

- Jeff
Click to expand...

Thanks Jeff. Trust me. I spent hours yesterday searching through a lot of Youtube videos and other online resources through google. I think I clicked on every link for the first 2 pages under those same search words.

It appears the original IC that worked great for this is the LM3909 IC chip but its been discontinued and out of production for many years now. From the hours I spend searching, ive found quite a few recommendations of using the 555. Some say there is trouble getting anything under something like 12 volts to turn on one of the transistors to make it work. But then ive also found youtube videos of guys using a 9 volt battery in the circuit. Which tells me that its likely the capacitor thats enabling the transistor to get the current it needs.:confused:
 
I think you meant "charging voltage."

A fully charged Lipo will be at 4.2V per cell. At the low current consumption of a EOT diode, the voltage will drop very slowly.

While I would never discharge my R/C aircraft Lipos down to 3.0V per cell, at the low discharge rate we're talking about, 3.0V is probably safe.

- Jeff
 
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