Friday, November 20, 2009

TBs TechTips 28 - Connecting the PF Receiver to 9V (III)

TBs has already hosted two stories about how to connect an IR-Receiver to a standard 9V LEGO battery box. The trouble with the IR-Receiver is that it doesn't draw its current from the same wires as the motor and so the extension/conversion wire doesn't work in this case.

The first solution involved using a PF battery box (without batteries) [1]:

The second solution consisted of using small strips of aluminium foil to short C1 and the 0V line as well as C2 and the 9V line [2]:

Today I tried my hand at a solution proposed by Rob Hendrix (Brickmodder) in BrickJournal 7.

The solution consists of prying the light grey connector of the conversion cable open (the one that is top PF and bottom 9V) and shorting out 0V with C1 and 9V with C2 from the inside:

Make sure to carefully push the bent black wires between the metal forks that are the bottom part of the connectors. Then place the 9V bottom part on top and press hard to close. Check to see if all the connections are good by using your modified connector to hook an IR Receiver up to a 9V power source. Disconnect and reverse polarity immediately if the IR-Receiver's little green light doesn't go on, as you might damage it if exposed for too long to the wrong polarity.


Unknown said...

it looks there is enough space for some diodes.
It could be best option.
Reciever will be protected.

Unknown said...

SMD diodes could be great for this job. :)

sarafiel said...

Oops. I don't want to open my PF wire connector. Just I use my idea cooking foil. o_O;

But I think, Vojtěch's SMD diode is very nice IDEA! I worried to my cooking foil idea damage to my IR receiver 'REVERSE Voltage'....

Jetro said...

I don't think there is any space to add extras. Keep in mind that the bottom part needs to fit in and that takes up what looks like free space to the sides of the wires. Also, in the second image of the opened connector you can see the four connector 'forks' and two additional notches. That's where the 'forks' you can see on the bottom piece fit in.

Or would you short the connectors in a different way?

If you ever do, please let us know and send some pictures.

Unknown said...

Wire diameter is 1mm.
SMD diode diameter is 1,45mm-1,6mm. Lenght 3,5mm.
I think that is possible.

Clement said...


I wanted to contact any of the editors of this blog (AVCampos ; Jetro ; Conchas), to ask your opinion about a new Technic website.

No email link is foundable on the blog ...

Could anyone contact me ? Thanks :)

(simply put the words separated by . in reverse order, giving : a.e.m[AAAAATTTTT]l.c)

btw : my name is Clement, 23, France, aka "JakoB" on Brickshelf.

TechnicBRICKs said...

The contact can be found through the profiles.
Easy but not too easy ;)

Have sent you e-mail meanwhile JakoB.

TechnicBRICKs said...

Guess something was wrong, with the address and cipher you supplied... ;)
Can't reach you.

Clement said...

My bad, the end is fr, not com. Sorry.

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