Gargoyle motion activated LED's and sound relay problem

[Camburger]

Hello!
I'm fairly inexperienced with circuits etc. but I know enough to have a bit of a tinker. I inherited a toy gargoyle with eyes that have red LED's in them. I decided to get a few parts and try and make it motion activated, so the eyes would light up on motion, and play a sound.

The eyes are working perfectly, however I don't think the relay is getting enough power to trip, so the sound isn't playing. I did notice that in one iteration of my setup, when i first turned it on, the sound would play. I can only guess that the initial power up had a spike, enough to trip the relay, but not repeatable after that. I tested it with a multi meter and the output of the PIR sensor is about 3v. I suppose my question is, what should I do to get the sound to play upon motion? I know that I could get a raspberry Pi or arduino involved but I'd like to keep it more simple than that if possible.

- Can/should I get a relay that requires less power?
- Can I use a component to boost the voltage so it can trip the relay?
- Is there an alternative component that could replace the relay?

Attached is my design, apologies for it's simplicity and I'm sure for breaking every convention in circuit design. Also I've attached the components I used.

Thanks in advance for any help.

 

[Brandyn]

The relay you have pictured requires 4v to activate. If your PIR sensor only outputs 3v that would cause the relay not to trip reliably. Have you tried a relay with a 3v coil instead?

Below is a link with information on the relay you are trying to use.
http://www.ic72.net.cn/pdf_file/f/290255.pdf

 

[73's de Edd]

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Sir Camburger . . . . . . . . . . . . .

Hot Dog . . . . .here . . . . . .

Looks like your PIR output is not quite high enough for the drive needs / threshold of that "Fiffy" dollah "Solidified Stately Relay."
Why not see if a 1 transistor addition will minimally fill your needs.
I used your same drawing technique . . . . . since it is all so familiar to you.
The X's are the two points where you need to disconnect / open that wiring.

New routing is performed thusly:

A FULL 5 volts supply line goes to the + of the SSR via BLUE line.
The former SSR - terminal now goes to the collector of the common NPN transistor, so that it will now depend upon its completed path to ground via the conduction of the added transistor from its C to E.
The somewhat now marginal voltage level coming out of the PIR unit is now routed thru a 100 ohm resistor to the base of the NPN transistor . . . . . . via the GREEN line wiring route.
The emitter of the transistor is connected to the common - line.

Since the LED eyes drive level was being adequate . . . . . we will not mess with that.

The low 100 ohm value is initially chosen to assure maximum conduction of the NPN transistor, it may later be increased upwards in value . . . . . but what the hey . . . . I figure that the accompanying sound clip is going to be short lived.

If this NPN transistor addition still doesn't get enough input drive level to the SSR . . . .we may have to revert to using a low Rss field effect transistor . . .try this mod first, though.






Thassssit . . . . . .


73's de Edd


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[Camburger]

The relay you have pictured requires 4v to activate. If your PIR sensor only outputs 3v that would cause the relay not to trip reliably. Have you tried a relay with a 3v coil instead?

Below is a link with information on the relay you are trying to use.
http://www.ic72.net.cn/pdf_file/f/290255.pdf

Thanks! I guess I assumed I couldn't get a relay smaller than 4v, after looking I found a few, so I've ordered 2 and I'll give them a try.

73's de Edd,

Thanks, I mostly get this, I might do a bit of research to understand further. Thanks for the suggestions guys

 

[Camburger]

Yaaaaaay! Thanks so much guys