Designing wireless controllers

[Jeffrey Schwartz]

I am designing a game that requires three players to wirelessly signal a
central unit whether their 'buzz in with the answer' button is pushed.
I had great success modifying Radio Shack wireless doorbells because
they have three different channels with three different carrier
frequencies. Unfortunately, when two players 'buzz in' nearly
simultaneously, the signals interfere with each other and I can't
properly detect them. I also tried using commercial TV infrared
controllers and receivers but, if two players buzz in nearly
simultaneously, the signals again interfere and the receiver gets
confused. I tried using a Holtek encoder-decoder scheme but, again, if
two players buzz in nearly simultaneously, the signals interfere. Any
suggestions?

Jeff Schwartz

 

[[email protected]]

Use fourier transform to determine which phase is earlier.

 

[John Fields]

I am designing a game that requires three players to wirelessly signal a
central unit whether their 'buzz in with the answer' button is pushed.
I had great success modifying Radio Shack wireless doorbells because
they have three different channels with three different carrier
frequencies. Unfortunately, when two players 'buzz in' nearly
simultaneously, the signals interfere with each other and I can't
properly detect them. I also tried using commercial TV infrared
controllers and receivers but, if two players buzz in nearly
simultaneously, the signals again interfere and the receiver gets
confused. I tried using a Holtek encoder-decoder scheme but, again, if
two players buzz in nearly simultaneously, the signals interfere. Any
suggestions?

---
Here's what I'd do:

I'd have the handheld units be transmitter-receivers, each with a
crystal oscillator and a counter which would start accumulating
oscillator clocks as soon as the button was pushed. At the same
time, a signal would be sent to the remote receiver (in the control
unit) which would cause the remote transmitter to send a signal to
all of the handhelds, at once, telling them to stop counting but to
hold the count. It would then query each of the handhelds, one at a
time, as to what number of clocks its counter had accumulated.
After determining which one had accumulated the largest number of
clocks (the winner) and lighting the lamp (or whatever) it would
send a signal to all of the handhelds which would clear the counters
and start another round.

 

[Ken Moffett]

I am designing a game that requires three players to wirelessly signal a
central unit whether their 'buzz in with the answer' button is pushed.
I had great success modifying Radio Shack wireless doorbells because
they have three different channels with three different carrier
frequencies. Unfortunately, when two players 'buzz in' nearly
simultaneously, the signals interfere with each other and I can't
properly detect them. I also tried using commercial TV infrared
controllers and receivers but, if two players buzz in nearly
simultaneously, the signals again interfere and the receiver gets
confused. I tried using a Holtek encoder-decoder scheme but, again, if
two players buzz in nearly simultaneously, the signals interfere. Any
suggestions?

Jeff Schwartz

Are there simple R/C model transmitter/receivers that can be set to
channels, and have the outputs fed to "Jeapordy" logic circuits already
available on several web sites. I have a 6 position unit that I would like
to "cut the wires" and go RF. I just haven't looked yet.

 

[Jasen Betts]

Are there simple R/C model transmitter/receivers that can be set to
channels, and have the outputs fed to "Jeapordy" logic circuits already
available on several web sites. I have a 6 position unit that I would like
to "cut the wires" and go RF. I just haven't looked yet.

yes typical RC transmitters are operate on separate channels unlike thise
doorbels, door openers, and infrared remote controls, which just use coded
pulses to diferentiate.

Bye.
Jasen

 

[Rich Grise]

yes typical RC transmitters are operate on separate channels unlike thise
doorbels, door openers, and infrared remote controls, which just use coded
pulses to diferentiate.

What about Radio Shack fob transmitters? Are they all pretty much at the
same frequency? I wonder if it'd be worth it to poke around with retuning
a set.

Thanks,
Rich

 

[Jasen Betts]

What about Radio Shack fob transmitters? Are they all pretty much at the
same frequency? I wonder if it'd be worth it to poke around with retuning
a set.

that'd probably require replacing the tuning component (SAW filtter or
crystal)

If only three transmitters are needed three of those cheap
golf-ball sized radio-controlled toy cars would have the neccesary
parts.

Bye.
Jasen