View Full Version : 555 timer circuit not work

07-25-2005, 12:23 AM
This relates to a previous topic from Parallax Forums>Public Forums>Stamps in Class> Ir remote control w/ BS2.

On /17/2005 Andy Lindsay posted a circut to transmit ir with a 555 timer. He also attatched a test frequency program and a test JVC transmit program.

I cannot get the circuit to work! i.e. cannot get it to tune or transmit.

Have done the following to no avail:
triple cked circuit
changed out every component with another one
used a separate 5v source for +5v other than VDD
changed out the 470 ohm and 1K resistors for 10K pot as suggested

I subsituted a visible led for the irt led to se if it would flicker with the pulsout's in the transmit program and it does not.
therefore must conclude that the circuit is not transmitting the pulsout(the led does flicker on a different 555 ir transmit circuit that was in BS1 ap note and also infrared weekend ap note for the bs2).

Has anyone worked with this circuit that might have some suggestions where I am going wrong?

http://forums.parallax.com/images/smilies/shakehead.gif http://forums.parallax.com/images/smilies/shakehead.gif

Philip Gamblin
07-25-2005, 12:27 AM
If you are building on a breadboard, it might be a good idea to check connections, component lead to component lead with an ohm meter. Breadboards can be the source of intermittent connections which can be a nightmare to deal with. There is lots of good information here http://www.parallax.com/dl/docs/prod/sic/IRRemoteforBoebot.pdf. I realize it is not JVC but there is a lot of general information on the IR remote function thet could help.

Post Edited (Philip Gamblin) : 7/24/2005 5:36:22 PM GMT

07-25-2005, 07:23 AM
Thanks Philip!

I shall do this or go to a whole new protoboard next; unless someone has another suggestion that solves this.

John Bell

Bruce Bates
07-25-2005, 07:35 AM
John -

In one of your posts you mentioned the following, among other things you'd done:
"used a separate 5v source for +5v other than VDD". When you did that, did you remember to tie all the grounds together to provide a common ground path?


Bruce Bates

Andy Lindsay (Parallax)
07-25-2005, 03:02 PM

I'm sorry the circuit isn't working. I think I still have that one built up at the office. If so, I'll send you a digital photo.