Thanks Richard, yes, this would be very suitable for Chieftain, indeed any tank. To illustrate what OpenTX and Beier can do together, here's another episode of "
Making a lot of things happen at the same time with one switch"
This combination of OpenTX on the transmitter and the Beier sound card in the model makes it possible to programme sequences of actions or functions and make them happen at precise times in relation to each other. It's also possible to execute it all with a single switch selection. The best example is what happens on firing the main armament. On the Cent:
- the firing sound plays
- the barrel recoils
- the barrel elevates and depresses
- the barrel smoker smokes and the fans pump smoke up the barrel
- the barrel laser lases briefly
All that is set up to happen when Switch C (a three position toggle switch) is moved from centre to down. The sound, recoil and jump happen once, the smoke and laser last as long as the switch is down.
This is all that lot in one picture:
To describe what's happening under the bonnet, I'll take each bit in turn, while remembering that a lot happens simultaneously in practice.
When Switch C is moved to down, Channel 9 on the transmitter goes to +100%. The receiver sends this information to the Beier (actually to Proportional Channel 7 on the EXM-2 expansion module).
Note that there's no relationship between channel numbers on the radio and the Proportional Channel numbers on the Beier - it just so happened that Prop 7 was convenient for wiring. Note also that on the EXM-2, there is both an input and output terminal for most Prop channels. This allows the signal to "pass through", picking up a function or sequence on the way.
This is where the magic happens.
Beier offers "multifunction sequences" which allow up to three functions to be triggered at the same time. In this case, when Prop 7 receives the message from Switch C, it swings into action and activates a Multifunction which:
- plays the main armament firing sound (Additional Sound 4)
- plays Servo Sequence 2 (see below)
- sends Servo 3 to Position 1 (see below)
Clever stuff. The main armament sound is actually a file with the commander giving a fire order, the loader loading a round and the gun firing. You then hear the sound of the empty case hitting the case basket and the sound of the round hitting (missing?) the target. This sound file is played without delay. The actual gun firing happens about 0.7 secs into the sound.
Beier can programme a servo to move to a number of positions at precise intervals. When Multifunction 1 becomes live, Servo Sequence 2 is called up. This activates the recoil servo:
Here's the Servo sequence for the recoil servo:
To describe what's happening, the servo starts at the fully run-out position (Position 1.010ms). After a delay of 0.8 secs to allow the fire order to play and the gun to be loaded, the servo moves the gun to Position 2 (2.000ms) at the fastest speed (0.1 secs). (This is the fastest Beier allows but the servo itself can't manage anything like that. Beier is simply saying move as quickly as you can). The run remain at full recoil for 0.1 sec and then returns to battery, at a slower rate, taking 2.0 secs). The beauty of this system is that you can play with both the timing and speed to tune the recoil both to match the sounds and to look right. The positions of the barrel can also be fine-tuned to eliminate any overrun.
So that's sound and recoil. I also described simulating platform rock and gun jump in a previous post. That's done in OpenTX, using a couple of Logical Switches and a Special Function, which cause the barrel to elevate slightly whenever the recoil servo operates. This shows the power of combining OpenTX and Beier.
Finally, back at the radio, this whole thing was kicked off by the transmitter telling the smoker stuff to fire. (Channel 9 goes to +100%, read at the Beier as Proportional Channel 7 going active. When the Multifuncion is activated, the third function sends Servo 3 to a set position. Servo three is actually the relay which controls the barrel smoker, fans and barrel laser.
The relay controlling the barrel smoker, fans, barrel laser is set up to be latching, ie it moves to shut (=ON) as long as there is a signal. In practice, this means that the smoke and laser will continue until Switch C is returned to central. It's very useful to be able to control the duration of the smoke and laser in different wind conditions. In stronger winds, the smoke dissipates quicker, so a longer pulse is needed.
And all that above took about two months to work out and lasts about two seconds when played. Such is progress.