Door Servo Research

Happy New Year everyone. Slow day today. Doing some research for my door panels and servos needed.

Been chatting back and forth with Chris Grootjans in Belgium on how he went about it. Here’s a cool video of his setup using micro servos directly attached to the Robart Hinges. I really like the solution because it doesn’t need any extra push rods etc and everything is more self contained.

Full details of Chris’ setup can be found here.

Right now I’m toying with the idea of just ordering a few mini servos from ebay. Typical cost is $20 shipped for 4 vs buying them domestically where one would cost at least that much. Size is around 22mm x 27mm x 11mm, but I’ve seen them as small as 20x17x9.

Update: I never did receive my servos from china, so buyer beware, the good news PayPal refunded my money.

Posted by Chris on January 1st, 2008 in General | 6 Comments

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12 Channel RF Remote Notes

There was some discussion on the builders message board recently about reprogramming the unique encoding on the newer 12 channel RF remotes.

Much of the documentation and notes on various R2 sites are for the older remotes. I thought it might be a good idea to document my findings on the new remotes.

I don’t want to repeat in detail why or how R2 builders use these boards, but the most common is to trigger sounds in your droid when combined with a CF3 sound system. Most of what’s been written about integrating the board into your droid applies no matter which revision you have – but changing the encoding has.

First up, most people find these boards on ebay. Just search on “12 rf remote” and you’ll find a lot of sellers offering them from all over the world. Don’t pay more than $30-40 with shipping. There’s still a few sellers offering the older boards too.

So what’s the difference between them? Not a lot to be honest. The newer boards are easier to reprogram the unique identifying code, and the transmitter is a little smaller. However the new receiver board does have an annoying buzzer that needs disabling.

For the geek in you – On the receiver board, auto learning decoding scheme has been programmed into the MCU IC chip, and inside the remote control or transmitter there’s an Encoding IC Chip, an SC-2262. This set of IC chips can be used to encode your signals so that multiple remotes in close proximity will not interfere with each other. In theory you can pick from 6561 different combinations.

Do you need to worry about changing the code? That’s easy, most boards are shipped with the same factory default code, and you don’t want your droid to clash with some else’s.

For reference, here’s the older board and the remote which is somewhat larger

If you have one of these then jump over to Alex’s original RF remote tutorial.

Warning: The Positive/Negative terminals are swapped on the new and old boards. Please double check everything you’re doing with the latest wiring diagrams from the manufacturer. Don’t assume this tutorial is up to date.

And, here’s the new RF remote/receiver – notice the circle/tab toward the back of the board. That’s the buzzer. If yours has one of these then you have the newer board.

Unlike the older board, to change the unique encoding all you have to do is set it on the remote transmitter and then set the receiver to auto-learn mode, with a press of a button and you’re done. Well that’s the overly simplified explanation.

Here’s an overview of the receiver board with the location of the learn button marked at the bottom left.

Procedure to Learn and Erase Codes

  • Press the “Learn” button on the receiver board, the siren will beep indicating the receiver is ready and waiting to learn from transmitter.
  • Press any designated keys to teach and select Output modes. (See list below)
  • If you need to reset/erase the the receiver due to lost or new remote, press “Learn” button for ~10sec until the siren beeps 3 times, which indicates previous learned codes have been erased.

Output Mode selection

Press 3 for Momentary Mode
Press 6 for Latched Mode
Press 9 for Toggle Mode
Press 12 for Ch1-Ch6: Toggle Mode, Ch7-Ch12: Momentary Mode

To set the encoding, first open up the transmitter

The chip at the bottom labeled SC-2262 is what does all the work.

Remove one more screw and separate the green circuit board from the casing

Notice the 3 rows of 8 little solder tabs at the bottom. That’s where you set the unique code using a soldering iron (one of 6561 or 3×8 combinations.)

Pin 1 through 8 bring out the Encode function of your remote transmitter. The receiver board will automatically learn from the transmitter by pressing the learn button.

On the older boards they used to labels the back of the board with a “H” for High, “L” for Low and numbers of the pin outs. Unfortunately the newer boards don’t have this luxury. I’ve marked up a photo to show the pin outs.

Low or ” L” – Low digital state (Close to GND level).
High or ” H” – High digital state (9-12V).

You should also be able to figure out the “L” and “H” states yourself. After you connect the system to power, use a Voltmeter to measure the contacts on both sides of the column of eight pins (1-8). Voltage level on each side should be consistence. If one side is “H”, the other side should be “L”. “H” level voltage can be measured only when signal is transmitting/receiving. Or simply use the above photo as reference.

Also, you don’t have to connect all eight pins to High or Low, just one will do. In my case pins 3 and 4 are connected to Low, and 7 to High.

Often remotes are default encoded to be 00000001, i.e. pin 8 is shorted to GND.

Encoded IC has following representation:

If the pin is not shorted to anything, its code value is “0”.
If the pin is shorted to Low, its code value is “1”,
If the pin is shorted to High, its code value is a “2”.

A couple of useful sites

  • Light Object – they sell on ebay under the name of coldfusionx, are based in the USA and a lot of R2 builders buy their boards from them. This link has a bunch of support documentation on it.
  • – Jerry Green’s write up on integrating the remote with a CF2 sound system.
  • – Alex’s original RF remote write-up.

Warning: I’ve just been informed that the Positive/Negative terminals are swapped on the new and old boards. Please double check everything you’re doing with the latest wiring diagrams from the manufacturer. Don’t assume this tutorial is up to date.

Posted by Chris on November 30th, 2007 in Electronics | 25 Comments

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