Anyone recognise this receiver?

[Pommie]

I have a 433 MHz receiver that I know nothing about.
Here's a couple of pictures of it,

And,

The black wire on the right is an aerial.
The 3 pins on the left are power and signal.
The top pin on the component side (lower picture) seems to have Vcc written next to it.
However, the other two pins have nothing.
On the bottom of the board there are two connections labeled SCLK and GND. The first could be Serial Clock but with only 3 pins I can't see how I²C could be a possibility. The second could tell me where ground is on the connection.
Does anyone recognise this board?
I can probably work out which pin is Ground but still have no idea what voltage it needs!

Any help greatly appreciated.

Mike.

 

[Doug]

The receiver for key fobs

 

[Doug]

On our Subaru it was key fobs and tire pressure sensor receiver

 

[Pommie]

Do you have any information?

Thanks,

Mike.

 

[Doug]

No. Sorry

 

[rjenkinsgb]

I'd guess it is just serial data out, that only needs a single data pin.

Is it an add-on for a garage door motor unit?
With no fixing other than the connector pins, I doubt its from anything portable - unless its an "Arduino module" grade device.

Any visible numbers on the IC? The photo is not sharp enough to read the numbers on the PCB, even.

 

[Pommie]

I think it's for a car and no numbers are visible on anything.

Mike.

 

[Nigel Goodwin]

Power, ground, serial out - just stick power on it, stick a scope on the third pin, and press a button on a transmitter.

 

[Pommie]

Voltage? As I said, I'm pretty sure I can work out which pin is which but no idea what voltage to apply.

Mike.

 

[Nigel Goodwin]

Voltage? As I said, I'm pretty sure I can work out which pin is which but no idea what voltage to apply.

Mike.

Try 5V for a start, and monitor the voltages on U2, which is probably a voltage regulator - as it's a car receiver, it's probably 12V in, and 5V out?.

 

[rjenkinsgb]

Can you post a better photo, with the components and traces clear so the connections can be traced?

 

[Pommie]

This is the clearest picture I can get,

It's size is 27.5x17.5mm.
I know there are numbers on the chip but I just can't read them.

Mike.

 

[Lightium]

I can see part numbers, but your gonna have to get a flashlight(or good directed lighting) and a magnifying glass and read the number for yourself.

 

[Lightium]

I can almost read out U2, but almost and good enough.

 

[Nigel Goodwin]

I can almost read out U2, but almost and good enough.

Easier, and faster, to stick 5V on Vcc and run a meter round U2

Even if you can read the number, it might make no sense. There doesn't look to be a reverse protection diode though?.

 

[rjenkinsgb]

This is the best I've found so far; it appears to match the IC on the module as far as visible power, ground, RF and crystal pins?

http://www.cmostek.com/download/CMT2300A-EN-Rev0.7.pdf

I don't know is it has a configurable UART mode, or if there is an alternate in the same series (or from whatever maker this is a second source for??) that has alternate data modes...

 

[schmitt trigger]

U2 has the trappings of a voltage regulator. If you can measure continuity from the center pin to ground, then that will confirm it.

As Nigel mentioned, first apply 5 volts, and probe around. Then slowly increase the voltage to 12 volts.
Next is to use a garage door opener to see whether you get any activity on the serial pin.

 

[Lightium]

I can almost read out U2, but almost and good enough.

oops. I meant "but almost ain't good enough".

 

[ZipZapOuch]

This is the clearest picture I can get,
View attachment 144373
It's size is 27.5x17.5mm.
I know there are numbers on the chip but I just can't read them.

Mike.

Set the board on a table next to a shoebox (or similar sized box). Set the phone on the box but overhanging to it can take a photo of the board. Use the time delay on your camera so you're not touching the phone when the shutter releases. Also, use the flash and touch the screen to tell the phone to focus on your PCB. Then trigger the shutter and wait for the photo.

 

[Pommie]

I'm using a Cannon DSLR EOS 600D so not sure if phone will be better. However, will give it a try. Gonna be tomorrow now as I've had a rather hectic day.

Mike.