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Old Dec 14, 2011, 11:01 AM
hacker
Canada, BC, North Vancouver
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Quote:
Originally Posted by flashervn View Post
I had a look at the tgy.asm
Which line do I need to change?
Line 112 says".equ STOP_RC_PULS = 1060 ; Stop motor at or below this pulse length"

Is this the one?
Yep! Note that boards with external oscillators and the typical internal resonator at a normal temperature are not quite the same. The ones with (and using) the external 16MHz oscillator should line up exactly with the numbers in microseconds, but the internal rc oscillator ones will drift quite a bit based on temperature.

I was testing the RCTimer 20A (which is just like the Plush 18A) in my RC Car, and it works well, but as it heats up the internal oscillator drifts and thus shifts the area of the neutral throttle zone, which means I have to keep adjusting trim. It probably makes more sense to use boards with external oscillators in this application.
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Old Dec 14, 2011, 11:40 AM
g0t rabb1t?
ABLomas's Avatar
Lietuva, Vilnius
Joined Jul 2011
1,306 Posts
Mystery 50A BEC

Here are pictures of Mystery 50A BEC.
Few interesting details about it:
  • low price
  • BEC is separate from ESC, so in multicopter setups can be cut (not needed in most setups)
  • Photo in DX site says it's suitable for 4S and more (i bought it for use on 4S), but received with 2-3S sticker. Will test on 4S, maybe that's just BEC limitation
http://www.dealextreme.com/p/mystery...icopters-34337
If they work on 4S, then maybe possible to flash them (no ISP pads but probably can trace legs).
Weight without BEC and heatshrink - 24.8g, should be ok for any, non-micro, copter.
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Old Dec 14, 2011, 11:44 AM
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VA
Joined Nov 2009
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Quote:
Originally Posted by flashervn View Post
I had a look at the tgy.asm
Which line do I need to change?
Line 112 says".equ STOP_RC_PULS = 1060 ; Stop motor at or below this pulse length"

Is this the one?
Yes that is the one. Before you go setting it to something else there is a very good reason it is set to what it is. The esc will not care whether you are just plugging in your battery or not. If it is powered and receives a pulse longer then what you set it for it will come on and most boards do send a pulse on powerup to keep the esc happy. If you have one that starts quick and smooth I would leave that at 1060 and then maybe set the next fastest starting one to 1050 and so on. For whatever reason mine timed up close enough at 1050, 1040, 1030 and 1000. Also I manually commented out all fet pinout includes except the one I wanted which was tgy.inc. Tried tweaking a few other things but didn't improve performance that I could tell. Make the changes and then save the asm with a catchy name and you will be ready for avrstudio.
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Old Dec 14, 2011, 11:49 AM
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VA
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Quote:
Originally Posted by simonk View Post
Yep! Note that boards with external oscillators and the typical internal resonator at a normal temperature are not quite the same. The ones with (and using) the external 16MHz oscillator should line up exactly with the numbers in microseconds, but the internal rc oscillator ones will drift quite a bit based on temperature.

I was testing the RCTimer 20A (which is just like the Plush 18A) in my RC Car, and it works well, but as it heats up the internal oscillator drifts and thus shifts the area of the neutral throttle zone, which means I have to keep adjusting trim. It probably makes more sense to use boards with external oscillators in this application.
Yes and one set of mine had enough drift that timing them from a warm room and then taking them out to a cold outdoors gave them enough pulse to come on as soon as I plugged the battery in

You guys be careful if you decide to mess with the code.
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Old Dec 14, 2011, 01:21 PM
hacker
Canada, BC, North Vancouver
Joined Dec 2010
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Originally Posted by pug398 View Post
Yes and one set of mine had enough drift that timing them from a warm room and then taking them out to a cold outdoors gave them enough pulse to come on as soon as I plugged the battery in

You guys be careful if you decide to mess with the code.
But they shouldn't arm (no 4th beep) unless they do receive zero throttle, so all they can do is "drift across the line" to a slow start, but they won't arm if they would run at the current pulse length (as measured at the rate of the drifting oscillator).
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Old Dec 14, 2011, 02:25 PM
manuLRK
Belgium
Joined Sep 2004
1,517 Posts
car option in action

manu

SimonK esc firmware (0 min 58 sec)
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Old Dec 14, 2011, 02:46 PM
hacker
Canada, BC, North Vancouver
Joined Dec 2010
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Quote:
Originally Posted by ABLomas View Post
Here are pictures of Mystery 50A BEC.
Few interesting details about it:
  • low price
  • BEC is separate from ESC, so in multicopter setups can be cut (not needed in most setups)
  • Photo in DX site says it's suitable for 4S and more (i bought it for use on 4S), but received with 2-3S sticker. Will test on 4S, maybe that's just BEC limitation
http://www.dealextreme.com/p/mystery...icopters-34337
If they work on 4S, then maybe possible to flash them (no ISP pads but probably can trace legs).
Weight without BEC and heatshrink - 24.8g, should be ok for any, non-micro, copter.
Hmm, it's the same price as the 10A board. It's really hard to tell the routing from that picture, since it must almost all be vias under the chip. However, it looks quite similar to the RCTimer 50A board. If that's the case, verify the gate driver pins (middle two pins on the left/top of the gate drivers, as I recall) route to the port D pins as described by this target .inc: https://github.com/sim-/tgy/blob/master/rct50a.inc , and that they're not inverted, and maybe that target will work (just pushed).

Also, I just pushed the unified start/run code, which seems to work. I'll test a few more ways before uploading a build. I had also a patch (now reverted) to separate start commutation timing from start edge crossing, which helped the reversing direction under load case for me, but broke normal commutation timing at low RPM. I'm still not happy with the direction reversing (not sure why everyone else is ) since it still sucks if you skip the neutral zone where the brake is applied. I'd rather it brake when it knows it's spinning the wrong way from the requested direction until it stops, then restart. The problem is that it can't get feedback while doing a full-on brake, so it has to do pulsing (which encourages regeneration). The full-on brake also feels like it will tear the magnets off of some of my motors, though I do notice other commercial ESCs do it, so it probably should still be an option.
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Old Dec 14, 2011, 02:50 PM
hacker
Canada, BC, North Vancouver
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Originally Posted by alll View Post
manu
Hey Manu, which servo tester is that? The HobbyKing one kind of sucks as it has only 4Ás resolution.
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Old Dec 14, 2011, 03:20 PM
manuLRK
Belgium
Joined Sep 2004
1,517 Posts
Quote:
Originally Posted by simonk View Post
Hey Manu, which servo tester is that? The HobbyKing one kind of sucks as it has only 4Ás resolution.
Turnigy 760LV-HV Dual Pulse Width @ HK

I did not measure the resolution, i will try tomorrow.

PS: i didn't test the car/break option under load, and higher amps...
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Old Dec 14, 2011, 03:30 PM
manuLRK
Belgium
Joined Sep 2004
1,517 Posts
Hi Simon,

Could you post a small sketch (scanned draw by hand) that explain the principle on determining the gate pinouts?
If it is too complicated, just some basic hints to get started.

Thanks,
manu
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Old Dec 14, 2011, 05:17 PM
hacker
Canada, BC, North Vancouver
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Quote:
Originally Posted by alll View Post
Could you post a small sketch (scanned draw by hand) that explain the principle on determining the gate pinouts?
It needs some pictures to really make sense (there are three basic layouts: P-FETs and N-FETs with NPNs on the P-FETs, all-N-FETs with NPNs on the high (originally P) side, and all-N-FETs with gate driver chips -- usually 8-pin things per phase). But for now, I pushed some updates I was working on to the README here: https://github.com/sim-/tgy (scroll down)
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Old Dec 14, 2011, 08:33 PM
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VA
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Quote:
Originally Posted by simonk View Post
But they shouldn't arm (no 4th beep) unless they do receive zero throttle, so all they can do is "drift across the line" to a slow start, but they won't arm if they would run at the current pulse length (as measured at the rate of the drifting oscillator).
You definitely know whats going on more than me

I had a different board on it at the time that has a short delay when it is powered up with no esc signal then goes to outputting low signal. As best I could gauge time it was when it started outputting low signal the motors came on but slow. Doing very well with new fc and avroto motors.
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Old Dec 14, 2011, 09:08 PM
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Joined Sep 2011
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Thank you simonk and pug. I did not try to run the ESC through my FC(DJI) but I ran it straight from a Rx throttle channel. I will test with my FC tonight when I get home before messing with the code> It litterally IS a code to me as I have no idea what it does and what what means. Cheers

Minh
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Old Dec 15, 2011, 12:58 AM
Maiden>Confident>Cocky>Crash!
argo-2's Avatar
New Zealand
Joined Feb 2010
550 Posts
Quote:
Originally Posted by alll View Post
Turnigy 760LV-HV Dual Pulse Width @ HK

I did not measure the resolution, i will try tomorrow.

PS: i didn't test the car/break option under load, and higher amps...
Price is right at $8!
Nice vid manu - by the way,fancy looking clamp/vice you've got there
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Old Dec 15, 2011, 02:55 AM
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Quote:
Originally Posted by simonk View Post
Yep! Note that boards with external oscillators and the typical internal resonator at a normal temperature are not quite the same. The ones with (and using) the external 16MHz oscillator should line up exactly with the numbers in microseconds, but the internal rc oscillator ones will drift quite a bit based on temperature.

I was testing the RCTimer 20A (which is just like the Plush 18A) in my RC Car, and it works well, but as it heats up the internal oscillator drifts and thus shifts the area of the neutral throttle zone, which means I have to keep adjusting trim. It probably makes more sense to use boards with external oscillators in this application.
Hi Simonk,
A friend of mine confirmed that the RCTimer 40A I am having are using internal crystal ( not sure its the same with the "internal oscillator" you are talking about). I tested again today and just like you ve described it, the jerky motor at 10% throttle only happened the first time. As the ESC heat up, its gone. So I think I am experiencing the "internal oscillator drift" you were talking about. Is there anyway to fix this and does this mean I should not use this ESC with your firmware as it wont work? Thank you.
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