Whatya think of this ?

[Silverleaf]

Having never dealt with electronics, I'm wondering if this would be worth it...or if it falls into the categorry of:

" You get what you pay for " and " Too good to be true "

https://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=2567&item=5905313092&rd=1

Just curious,

 

[Elapid]

makes me very suspicious.

looks like a rookie job...

 

[shockwaveriderz]

I would advise spending $25 at perfectflite for thier mini or micro timer......

 

[Hospital_Rocket]

Looks like a Fairchild NE555 timer and the supporting circiuitry set up as a one-shot or monostable multivibrator. From the picture I do not see how to set the time. You probably have to change out the resistor you see at the top right of the IC.

This is probably the circuit diagram

Monostable NE555

If you ground the input called trigger, the device switches state for a defined time. The time is set by the relationship of R1 and C1. This circuit is similar, however you would need to figure out how to use the output to go positive instead of negative, That would involve the relation ship of R2.

One thought, though for $10 it might not be a bad thing to use in a rocket you are afraid of losing. I would insist on seeing some sort of instructions for setting the time and an underside view before I bought it.

One thing I do not see is any positive retention of th IC.

Also, I do not see any output buffering. That means the IC directly drives the output, This limits the switched current to around 100mA.

 

[Silverleaf]

Al,

Many thanks for the detailed information. 8)

I'll probably bypass this auction, since I'm not ready to invest in electronics at the moment, but even before I do that, I need to learn how the electronics actually work. lol

Cheers,

 

[Micromeister]

Silver:
Shockie is right, Perfectflight mini and micro timers are Great and can fit in some really tiny spaces if powered by a couple supercaps they can be used in 10.5mm tubes. light enough for mini to micro motor staged models

 

[Chr$]

yeah, 555 timer circuit and probably a switching transistor to sink the current to the igniter.

The guy probably has pretty close to 10 bucks in parts there, so I guess his time isn't worth much.