K8055 Contact closure for 315Mhz remote

Kits PC Related Projects
1

Hello all,

I am attempting to use a K8055 to close switches on an 315Mhz RF Tx so that I can control some motors via wireless.

Looking at the circuit board for the RF Transmitter there are 12 switches. I have de-soldered them. If I short between the two leads where the switches were, the RF Transmitter actuates the receiver end just as you would imagine.

Now on to the Velleman K8055. I am wiring it up as follows:

One lead of the switch goes to digital output 1 on the Velleman. The other lead on the switch goes to clamp. I have a 1.5V battery going + to clamp and and - to ground. Using the Velleman demo software I activate output 1. Nothing happens. Ive tried it feeding Clamp/Ground with the Velleman 5V and also with no voltage.

At one point it did work, but it seemed when I got past the second or third output it stopped. I have tested the outputs and they seem to work fine (switching a relay coil).

The odd thing about the Transmitter is it seems that the switches are wired in series somehow (One half of the switches through the next etc…). Not sure why or if that is the problem in using the open collectors to close the circuit.

Any thoughts? The unit I am using is: gamainc.com/cgi-bin/products.cgi?item=RF340-4PR

Thanks!

Bryan

2

[quote]One lead of the switch goes to digital output 1 on the Velleman. The other lead on the switch goes to clamp. I have a 1.5V battery going + to clamp and and - to ground. [/quote] You may try: One lead of the switch goes to digital output 1 on the Velleman. The other lead on the switch goes to GND on the Velleman. No battery. No connection to the CLAMP.

3

I will try that. Sort of makes sense. Effectually ground to ground then when output is activated.

Thanks… Ill report back for posterity

4

OK that worked, sort of. Apparently this TX sends a positive for the up control and a negative for the down control. So the way I wired it now, (one switch lead to k8055 output and the other to ground) the up/motor one way, and down/motor other direction switches now both do the same thing. My brain hurts…

Any suggestions? Any way to make these two boards work together?

Thanks
Bryan

5

Here is a pic of the TX board if anyone is interested

6

[quote]Any way to make these two boards work together?[/quote]This may be difficult (or impossible) if the switches on the remote board are floating i.e. not connected to common GND on the board.

7

Im thinking since the two leads just need to be shorted to activate the switch, that I should use an SPST relay on each switch, and hook each lead to Common and NO. Then relay coil to 12V/Clamp and K8055 digital output. I only need 4 switches, so that’s not terrible.