Help for surgical table hand controller

[Boogeyman]

I’m new on this forum. I need some help for a surgical table hand controller but first here is a little background;

I work for a medical faculty in Montreal in the anesthesia department and a used surgical table (amsco quantum 3080 rl) was recently donated to us. It works perfectly fine and students love it. The only problem is that it didn’t come with the hand controller. I have a little bit of electronics knowledge and thought that I could built a controller here. The reason we want a controller is that it recreates the realism of a surgical room.

As it is we have to bend down under the table every time we want to change the table’s position. I managed to get my hands on the original controller schematic diagram and it is more complicated than I expected. See the pictures below.

We don’t even need all the controls. All we need is Floor lock, Back, Trend, Height, On and Off/Stop (the rest is optional). We don’t even need the leds (sure would be nice though)
Does anyone could help us figure out how to make this? Since our school budget is already low, they couldn’t unlock some funds to buy a new one. The simpler the better.

If you can’t help with this, I was thinking of just putting a parallel circuit with the switches that are located under the table. What do you think? Did I bite off more than I can chew?

Thanks guys! Hope you are all well!

P.S. We don't use real patients on it, only medical manikins

Diagram:
http://tinypic.com/r/2ivb42p/5

 

[(*steve*)]

You may be able to get by with remote switches in parallel with the ones under the table.

My only concern would be safety if these are at mains potential.

Looking at that circuit, it appears to me that the interface is using some serial data transfer (RS232?).

The circuit also uses a microcontroller and without the software you could make the controller but it would not function.

The only chance of making a controller is to find some information on the protocol used by this interface. If you could, a replacement controller could be considered.

 

[Boogeyman]

Sadly I don't have access to the software for the micro controller.

For the parallel circuit I wasn't planning on using remote switches. The original controller is not wireless so it has a cable connected to the table. I would also make one with a cable to keep it as real as possible. Not sure if the switches are at mains potential though.
I would try to be extra careful with wiring and isolation.

Thanks for the answer!

Really appreciate it

 

[(*steve*)]

Yeah, when I said remote switches, I was meaning remotely connected via a cable.

I wouldn't even be advising you if the table were for real patients. But since they're mannequins it's OK.

However, the people using the remote control are not dummies (or maybe they are, but they're not mannequins, and at thus more problematic if you damage one and need a replacement...) so you want to be safe.

If the switches have mains potential (or anything above 24V), I would recommend using relays and controlling the relay remotely. This is also good advice if the switches actually carry the motor current. At high voltages it's dangerous, at low voltages the current is high and the length of the cable could induce a voltage drop.

 

[Boogeyman]

I like the relay idea. I even have some laying around.
I'll try to get a hand on the table's schematic diagram before doing anything since I'm the one controlling it.