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Old Jan 03, 2003, 04:04 PM
rebmeM roineS
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Rockingham, Perth - Western Australia
Joined Apr 2001
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'Snowglobe' Rx:



www.microne.com/edoc/files/ME301-English.pdf
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Old Jan 03, 2003, 05:21 PM
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Thanks for the photo -- it is a surprise! The info that I have suggests that the RX2 Rev B IC has the internal DC-DC controller feature. From your Rev B equipped board, it is obvious that is does not.

My COB based Rx's use a cheap NPN (BV4) as the DC-DC driver. If they are Rev B's I will never know. I am going to have to assume that they are Rev C's.

I will update the web page to indicate that only the Rev C part has the built-in controller function. If anyone has any additional info on the older rev parts (pin 8, LX output) please let me know.

For those of you that are removing the DC-DC parts to reduce weight, the concepts previously outlined remain the same. Just change "NPN" to "3 (or 4) pin SMT part."

Regards,
Mr. RC-CAM
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Old Jan 03, 2003, 06:25 PM
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I've added the DC-DC info to the web page. It now addresses the Rev C part differently than the earlier versions. It also provides a link to the ME301 controller IC (info may be of use to the page's visitors).

Mr Bungles -- Thanks for your help! Much appreciated.

Regards,
Mr. RC-CAM
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Old Jan 05, 2003, 04:44 AM
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Bitchar-G / Bitcharger Secretes Revealed!

Mr. RC-Cam et al,

I have the RX-2Bs like MrBungle. It came out of the Sno Globe clones marked "Super Racing". The maker's logo is "SC" and Realtek's is RMC and looks like a crab waving 2 claws. I have found no links to the "SC" logo and can find no links to the Action Division of Realtek off their site for info on these early revs.

I've played with this chip a bit and can get pin 12 to go hi when I ground pin 7 on the transmitter. Reverse is disabled and L & R turn turns the wheels but the motor runs full out. Grounding receiver pin 8 seems to have no effect.

The reason I was interested was I found a RC truck, no Xmitter. The receiver board has a 16 pin dip chip by Realtek marked RX2 88053Q1 but this board has fully proportional throttle and steering servo with multi positional sensors. Pins 8 & 9 are NC.

Are there other capabilities of these earlier chips we're missing?

Richard
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Old Jan 05, 2003, 12:34 PM
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Quote:
I have found no links to the "SC" logo and can find no links to the Action Division of Realtek off their site for info on these early revs.
Realtek was very open about the RX2/TX2 chips at one time. Then they spun off a new division called "Actions" and the chip info is now under lock and key. You must qualify to earn the right to see the data sheets. This is probably just a reaction to the chip design pilfering that goes on over in that part of the world. It is a silly restriction since a competitor can still get the data if they try.

Quote:
I've played with this chip a bit and can get pin 12 to go hi when I ground pin 7 on the transmitter. Reverse is disabled and L & R turn turns the wheels but the motor runs full out.
That is the method that was made available on the chip to obtain the old style "Turbo" mode. It is used to create a 2-speed model. It requires external components to implement. It certainly can be used as a general purpose output though.

Please see the RX2 output mode table that is at the bottom of this post. It will give you an idea of what is possible when the TX2's "Turbo" button is use. If you have a early RX2 chip (Pre new edition Rev-C) then only the old style turbo mode is available (same as Pin 9 unconnected).

Quote:
The receiver board has a 16 pin dip chip by Realtek marked RX2 88053Q1 but this board has fully proportional throttle and steering servo with multi positional sensors.
With a different encoder (not the TX2) you could implement a proportional system. If you spent some time with a scope you could reverse-engineer the encoding format. This info could be used to create a propo encoder using a microcontroller.

Quote:
Are there other capabilities of these earlier chips we're missing?
No doubt there are. One thing that is a bit interesting is that they seem to have changed the chip's features around without a Rev Bump indication on the chip package. For example, I understand that there are two editions of the "RX2C" (rev-C) chips -- old edition and new edition. The latter has the nifty PWM turbo mode.

If RealTek/Actions would be more open with their Applications Data sheets then we could see examples of clever ways to eek out more functionality of the chips. But as it stands, we must find out on our own.

RC-CAM
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Old Jan 05, 2003, 03:37 PM
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spudnutty

which truck?
where'd u get it?

what do you mean motor runs full out?
like faster than normal speed or is this on a revision c chip.
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Old Jan 06, 2003, 01:15 PM
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A street vendor was selling some microsizer cars and upon a closer look I noticed one model had an RX2 Rev B DIP chip in it. I bought the little car for review.

My o-scope shows that the RX2 Pin 8 appears to be passively pulled high. This confirms that the Rev B parts require an external DC-DC control IC (as shown in MrBungle's photo.)

The car is no longer needed -- I only bought it to make the measurement. If anyone wants to buy it then Private Message me. Price is at my cost -- $15 (plus $4.50 shipping, CONUS only).

I only have this one car for sale and it has NEVER been used. It is on 49Mhz and is unassembled, as shown in the photo below. It has the 2-coil steering actuator. It is just your typical cheap BitChar-G clone, so there is not much more to say about it.

RC-CAM
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Old Jan 06, 2003, 03:53 PM
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Las Vegas
Joined Feb 2002
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Quote:
..just your typical cheap BitChar-G clone...
Hell no, that's a "Goldlight" brand with "Ultra Cool Styling!"

Sorry, I couldn't resist. I did notice, however, that the box also says "With Special Motor." I wonder if it is more powerful than the standard BitCharger.

-John
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Old Jan 06, 2003, 09:28 PM
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Bitchar-G / Bitcharger Secretes Revealed!

Billy,
That was a typical big Radio Shack RC that I found in my neighbors trash along with the wrong Xmitter. If you're talking about Bit Char-G mods check out:

http://tinyrc.com/forums/showthread....ghlight=Hummer

Then search suvs, trucks, jeeps on this forum. These guys have done it all.
When I say it runs full out I meant at regular top speed vrs the half speed turbo option.

All,

Just bought this "Thunder Racer" at Walgreens Chicago for $9.99. I've taken 5 different clones apart and this is the best so far. I've never seen the inside of a Tomy but this one has a NiMH battery, 2 sided plated thru board, TX2C xmitter chip (Mr.RC-CAM, it has the Actions logo on it), LM393P voltage comparator by TI, cute loop receiver antenna ;-) and rollout xmtr antenna.

The Xmitter chip has encoded output with and without carrier (pins 7 & 8) but my scope says they're reversed from what this site says:

http://www.hlec.com.cn/pdf/TX-2RX-2.pdf

which gives a lot of information. Why does Realtek keep a secret that all the cloners know anyway or in this case a Realtek chip in a clone?

I can't get the 50% half speed to work but I do get receiver pin 12 hi when I ground Xmitter 6 but don't understand where it fits in the 2 channel setup.

I'll keep playing with it while waiting for some SMD MOSFETs from Mouser.

Richard
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Old Jan 06, 2003, 10:11 PM
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Quote:
http://www.hlec.com.cn/pdf/TX-2RX-2.pdf
Thanks for the link! That data sheet shows the full encoding format for the transmitted signal. Anyone that wishes to roll their own "TX2" style encoder should take a look.

Quote:
Why does Realtek keep a secret that all the cloners know anyway or in this case a Realtek chip in a clone?
I agree, it is seems silly at this point. Not much left to protect.

Quote:
I can't get the 50% half speed to work but I do get receiver pin 12 hi when I ground Xmitter 6 but don't understand where it fits in the 2 channel setup.
Only the very latest RealTek/Actions Rev-C RX2 are setup to support the PWM turbo mode. You can use the old style turbo output (pin 12) as a third channel (drop bomb, turn on landing lights, etc.). The RX2 output logic table is listed in my post shown above.

RC-CAM
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Old Jan 06, 2003, 11:32 PM
rebmeM roineS
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Rockingham, Perth - Western Australia
Joined Apr 2001
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Quote:
Originally posted by Mr.RC-CAM
Mr Bungles -- Thanks for your help! Much appreciated.

Regards,
Mr. RC-CAM
No, thank YOU for all the information you have provided, you seem to have much more time to spend on this than I do.
Before reading your site, I didn't realise that these were AM Tx's.
I can't understand why they are. (Maybe to overcome freq. drift of the Rx as voltage drops)
I wish I had more time to try playing around with FM, to see how many cars I could squeeze into the same freq.

Simon
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Old Jan 07, 2003, 04:04 PM
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Germany, NDS, WOB
Joined Nov 2000
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http://www.rodkrapong.com/electronic-part.htm

They have TX-2 and RX-2 chips cheap if anyone wants to experiment. Not SMD though.

Michael
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Old Jan 11, 2003, 10:43 PM
Rob H
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Australia, QLD, Cairns
Joined Jun 2002
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Thanks for the informative website Mr R C Cam - thanks to you I think I finally understand enough about the electronics part - I want to use the original motor etc so the last part of the puzzle to me seems to be what size prop will work.

thanks again

Flyfan
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Old Feb 24, 2004, 02:30 PM
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Joined Feb 2004
443 Posts
hello model builders!
I am Remy and I am here really,total new here.
I come from the Netherlands, so do not have pay attention to may English because itís really bat!
I hope that you can read and follow me a little bit,but I do my best!
IĎm self a elektro flyer,for approximately 7 years.
I have firstly done free flight for 3 years,and afterwards radiocontrolled planes.
Now enough of me:P
I sit in fact with a problem,and I canít find the answerL
I am with a bit plane now busy, and itself has the chip"ref c" build in it
So i have a small turbo on my transmitter
Kindest I want that.., if I push my turbo button in ,that the moter then the full power of the accu gets to see, but thatís only possible by adding a mosfet there.
Already a complete job for me becomes turn the fuctie's of my transmitter,because Iím not really a good electroexpert.
Buts that still must succeed.
(then iím possible to use 1 coil instead of 2)
what now actual my question is: How must I solder my mosfet on my print, where must I solder him,and what must I replace??
And it is all, however, possible? with one sense: Who has itself also a turbo on itstransmitter ,and how has he solved it?
Because Iím not a elektro expert,Iín not really good with reading schematics,so is must being easy to read them:$.
I know,its very hard to read,and I ask a lot,but I most to know it!
Has anybody also a turbo button on his transmitter,and also a fet soldered on hit receiver?
And cam he telle me step by step how I must do it>?
I have already build my plane,and tried to fly,but Iídonít have enough powerL..
People I hope everybode can help me!
Much and much thanks!
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Old Feb 24, 2004, 07:06 PM
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United States, VA, Clintwood
Joined Nov 2002
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Remy
Welcome to the ezone. Can you take a picture of both sides of your RX at good enough resolution to see the traces and components?
If so then I might be able to show you where to put the mosfet. I do not have any of the rev C boards but have added the mosfet to several revb chip boards. If you can not take a picture then I suggest looking at MR RC Cams site and look at the pinout of the revc chip then find the turbo pin. trace on your rx where the tubo pin goes to your motor. one of the transistors there in the path is one that you will have to replace. If you have changed around your controls so that motor goes to coil for using single coil it might be more complicated than just replacing a transistor with a mosfet. What kind of motor/prop/gearing are you using and what are the dimensions of your plane?

Billy
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