It works well enough for casual playing, as long as I don’t attempt some sonic blast beat china riding -) Right now, I still seem to reach 1.9 or so. 5 millivolts with a hard spike of 1 at max. I may need to play with it a bit maybe in another path, to see where I need to increase resistance to lower the voltage so that it is consistently between. I attempted to jump right to a 1M, but it reduced the sensitivity if I remember correctly. This caused the voltage to drop slightly more so that it triggers more reliably. I replaced the 100k variable with a 330k as well. I then added a resister after D2 to eliminate false triggers where the rim triggered the head. This prevented the choking or cut-off behavior. The first thing I added was a diode between VR1 and D1’s points. I noticed the values were off, where the switch / rim was too high. ![]() I see I can measure the piezo output, so I compared it to the OEM drum, and also compared that to my circuit output for both head/rim (Tip/Ring respectively). View attachment KeithRDTXpanderCheapB.pdf I only have a basic meter made by klein tools, so hopefully that is enough. Also, I can compare the stock RIM / switch signal to the output on the adapter I made. I think my next step which probably should have been my first, is to measure each cymbals output, and compare it to a stock OEM signal from a drum pad. I will swap again and compare.Įarlier in that thread, it was stated that the switch is looking for a. I have also tried replacing R2 with a 10M resistor, but it didn't seem to make a change. I will try putting that back to spec though and see if it cleans things up. I also replaced the 10k resistor (R1) with a variable for more control. I may be completely wrong, which is why I am here, but the loop looked to me that if the value is incorrect, it loops until dissipated to ground. Now instead of triggers that are cut short, those same triggers no longer fire, so the only triggers I do get are clean sounds/signals, but it does not occur every time.Īctually a point of correction I should make is that not every trigger fire is clean, as sometimes tapping that cymbal lightly fires the other circuit path which is the head/piezo input. The issue I am experiencing is that initially the cymbal triggering the RIM (which is converted from piezo to switch) was having mistriggers resulting in the sound being cut off prematurely.īased on the attached schematic, it looked to me that the loop at D1 may not prevent flow back to the Variable resistor, so I inserted a diode between VR1 and D1 to keep the flow on that side. That information is quite helpful, but I was wondering if someone could help me understand the circuit in full as this was the first circuit I have ever made, and have been learning quickly to the best of my ability and time availability. If you're playing the second pad, its piezo is used to determine the velocity of the hits and what's coming from this same piezo will make the circuit "link" the ring and sleeve parts of your socket. In circuits 1/3, if you're playing the first mono pad, its piezo transducer is used to determine the velocity and basta. In the 2nd circuit, the "main" piezo xducer determines the velocity of a hit, while the "aux" piezo xducer is use to trigger a kind of switch that determines which zone of your dual pad is played. ![]() R2 increases the sensitivity (more the value is, more sensible will be the detection) R1 limits the sensitivity (more the value is, less sensible will be the detection) Q1 acts as a triggered switch : basically, if there's enough current coming to its "base", Q1 allow what's coming from its collector to flow to its emitter. D1 and D2 won't allow a piezo xducer to make his buddy "buzz". ![]() I'm formerly not into analog electronics but here's what I understand from the schematics : Actually, Keith Raper is the man of the situation
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