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Open Source Sound Dev / Re: Open Source Sound using Teensy 3.2 and PJRC Audio Library
« Last post by LukeZ on September 25, 2017, 10:00:20 PM »
This is not a fault, but rather the consequences of the trade-off we were discussing earlier. If we need the maximum possible volume from any given sound at any given moment, we must accept distortion when multiple sounds are played simultaneously at full gain. But if we want to eliminate the possibility of distortion we have to limit individual sound volumes during synchronous playback at high overall volumes.

There is nothing you can do about it other than to adjust the volumes to 50/50 (or some other ratio lower than 90/90) or else only play multiple sounds when total volume is something less than 100% (you can adjust the overall volume from the transmitter using a function mapped to an analog channel). My original code took care of this automatically but as Jurgen pointed out the dynamic adjustments were definitely noticeable.

Using a 4-ohm speaker is a good idea. It won't directly address the issue discussed here but it will give you a louder sound for any given volume setting, so you could perhaps operate at less than 100% and thereby avoid distortion.

Ultimately we can re-design the board for a more powerful amplifier, with the same strategy as just described - if we make the total volume potential greater than actually required, the user can operate below 100%, leaving unused volume capacity available for distortion-free synchronous sound.

These limitations are common to any audio project. We perhaps do not notice them on other products because they pre-restrict the volume to begin with in order to avoid distortion, but here we give the user perhaps too much control such that the inner workings are more observable.
Open Source Sound Dev / Re: Open Source Sound using Teensy 3.2 and PJRC Audio Library
« Last post by dannydeleon on September 25, 2017, 07:11:09 PM »
Hi Luke,

 I also have your prototype open panzer sound card and have been doing some testing. I've updated the sound card firmware using teensy.exe and have set the 3 Sound sliders in OP Config to about 90%. I am using a Visaton FRS-7 8ohm speaker. I am getting really bad distortion when the engine and MG sounds play simultaneously. Individually, they soung great. I am just using your test soundset for now. Any suggestion on resolving this? Will a 4ohm impedance speaker help or using an amp? I can upload a video if you want to hear it.

Thanks, Danny
Open Panzer Help / Re: Dual recoil servo - Coelian & Maus
« Last post by LukeZ on September 24, 2017, 03:59:46 PM »
I didn't understand completely all that you said. However, if your dual cannons will fire at the same time then this is simple. You can attach more than one servo to the same output by using a "Y" servo cable. You can also attach multiple high-intensity flash units to the single output on the TCB (if you create a custom "Y" cable for them) - or to the Aux Output light if you are using LEDs instead. Without any changes to the firmware this already gives you two cannons that will fire together at the same moment (with a single sound).

But if we are to implement dual cannons that are not synchronized we will require further development of the firmware. It is not impossible, but it would be a substantial effort. To be honest I think at this moment time investment is probably not worth the payoff given how few models would implement the feature. Nevertheless I will add the idea to the to-do list so we don't forget it.

Those are some nice models though!
Open Panzer Help / Dual recoil servo - Coelian & Maus
« Last post by johnnyvd on September 24, 2017, 12:05:44 PM »
Hi Luke,

Would it be possible to have dual recoil servo's? Reason is i have a duo of Coelian's of which one has a free rotating servo and *nothing yet* on the other.

it would be great to OR drive separate servo's OR have two sound files playing (firing with shell dropping) where the sound file will not start if the "fire" button is released but the started file will continue playing ending with the shell dropping.
Also synchronising the two muzzle flash leds would be nice..

And there is the second scenario: E75/100 and/or Maus with dual cannon: both firing in sequence with one button OR a seperat trigger with seperate gun sound files.

Cheers, John
Scout Dev / Re: Home Build
« Last post by LukeZ on September 19, 2017, 02:47:21 PM »
Also as you build your boards please post over in the Assembling Boards by Hand thread to ask questions or share your experience.
Scout Dev / Re: Home Build
« Last post by LukeZ on September 19, 2017, 02:46:24 PM »
Yes, you can substitute many components with comparable parts, especially the passives such as resistors and capacitors. Obviously some substitutions are not good, as Hobby King discovered, if you have questions about specific components just ask.

W25Q128FVSG should work just fine, but note the sound card doesn't presently implement the flash memory at all. You can choose to leave it off along with R8 and C3. The flash memory was an idea I was playing with but so far it doesn't seem we will need it.

The important parts on the Scout are the thermistor, diodes, MOSFETs, motor driver, microcontroller and crystal, and the LDO (voltage regulator). Even among those, if you were careful and knew what you were doing you could substitute the thermistor, diodes  and LDO but just use the parts specified to be safe if you can.

The important parts on the Sound card would be the LDO, the micro-SD socket (get the wrong one and the footprint won't line up), and obviously the amplifier IC as well as the Teensy.

I agree SEEED is a great supplier. As for manufacturing, lots of places will manufacture boards but they all seem to want to be paid for it. :) Production runs are extremely expensive and I am not rich. I also don't believe there is any substantial profit to be made from selling RC tank electronics given the size of the market so I don't feel it makes economic sense for me to invest in this financially beyond what the development costs have been (which were considerable). So for manufacturing that really only leaves us with entities willing to shoulder the financial burden themselves... which is a small list indeed.
Scout Dev / Home Build
« Last post by Ncartmell on September 19, 2017, 01:17:22 PM »
I have just received some PCB's for the Scout and OP Sound from china (SEEED). Very good boards, 10 boards @ $4.90 plus $10 shipping, so total cost of $20. That is effectivelly $1 each and the boards have also been electrically tested.

You can also order a solder stencil but I wanted to see the quality of the boards.

The question, can I vary from the BOM.

For instance will non surge 1/10W resistors be ok?

The flash memory is W25Q128FVSG acceptable?

What parts can't be changed?

It also may be of interest that SEEED will manufacture fully populated boards.

I tried to get a price but was unsure if it was complete as there was a warning that all parts were not recognised.

It may be worth pursuing for a production run.

Best Regards

Open Source Sound Dev / Re: Open Source Sound using Teensy 3.2 and PJRC Audio Library
« Last post by LukeZ on September 12, 2017, 10:43:43 PM »
That's ok! It's a lot to remember I know. :)
Open Source Sound Dev / Re: Open Source Sound using Teensy 3.2 and PJRC Audio Library
« Last post by jhamm on September 12, 2017, 10:06:43 PM »
Hey Luke,
youré right!  ;D
I do not have defined an analog trigger source..... 8)
Sometimes i am so stupid! :o
Open Source Sound Dev / Re: Open Source Sound using Teensy 3.2 and PJRC Audio Library
« Last post by LukeZ on September 12, 2017, 09:21:52 AM »
Is the general Volume of the Sound card adjustable by Transmitter?
The Function "Set Volume" is greyed out...
Yes! This function should not be greyed out. Either it will be missing from the Function list altogether (if you have selected Benedini or Taigen sound card), or it will be present. But you can only assign it to an "analog" Trigger Source (such as a pot or lever on your transmitter). If you do not have an analog trigger source defined then you won't be able to use it.

There should never be a greyed out item in the Function List, if you see one please send me a screenshot.

If you still can't get it to work post your OPZ file for me to look at. 
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