I decided to give up the idea of using piezo transducers.
The DM6 has 2 switch inputs for Kick drum and Hi-Hat so I made a box to test the use of a footswitch to trigger both these drum inputs simultaneously. I also thought it would be a good idea for the drums to trigger on both the up and the down strokes of the footswitch.
The toggle switches on the front of the box will allow me to select up, down and both for the foot actions. It's a on-on-on switch like the type used for dual pickup control on a guitar.
It doesn't work when trying to trigger the same drum both ways. Also this type of footswitch has an awful action and is not suitable for precise foot drumming.
If I used a couple of footswitches with a better action and just wired them directly to the Kick and Hi-Hat inputs of the DM6 I could have a setup similar to Duster with the added bonus of 5 separate drum kits.
But I wanted to do more!
What I needed was a different approach. I decided that the way forward is to use some kind of active circuit.
Here is the design for a single foot switch. It has 2 identical circuits in it. One for up and one for down. It uses a 556 device which is 2 x 555's in 1 chip. There are 2 x 4 way rotary switches to allow 2 drums to be triggered by 1 footswitch for the following foot events:
Down - Off - Up - Up and Down
Now I can trigger 8 Drum sounds from 4 footswitches. I wired up 4 of the circuts into this retro style box. The outputs on the back of the box are connected to the 8 trigger inputs of the DM6. Although the labels show the names of the drums, any sound can be assigned to the triggers by setting up kits for the DM6 . This works very well except for the footswitches. I bought a couple of self-contained footswitches from Maplins hoping they would do the trick, but the response and feel of these switches made it very difficult to play accurately.
I need to find the perfect switches!