Car Seat Motors and Basic Stamp

nagi

I am trying to make a seating platform using car's seat motors. Basically, trying to make a 3-DOF. I know the motors are 12v driven.· Can anybody reccommed what the best route to take to interfacing with BS2. Has anybody done anything like this. Please provide any ideas, pointers, etc.

Really appreciate your help


thank you

nagi
MCP|MCAD|MCSD.Net
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Paul Baker

Do you know what type of motors they are? standard gearbox dc motors or stepper (look at the number of wires coming from the motor, are there 2 or more)?

Jon Williams

Read this to get started: http://www.parallax.com/dl/docs/cols/nv/vol1/col/nv6.pdf

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Jon Williams
Applications Engineer, Parallax
Dallas, TX· USA

nagi

Jon, Paul;
thank you for your reply.

Paul,
I believe these are std gearbox DC motors and I believe they have 3 wires (possibly for reversing). I am still a beginner in electrnics; so I may not speak the right jargon.

Any help would be appreciated.

thank you

nagi
MCP|MCAD|MCSD.Net
http://nagi.crosscity.com/
http://fstop.crosscity.com/

Paul Baker

hmm the third wire has me somewhat puzzled, usually dc motors have two wires, swapping the polarity changes direction (which btw I'm sure they are dc motors). Considering where these motor are being used, the third wire is quite possibly a brake (you don't want the seat lurching forward in an accident) Can you get a manufacturer and/or a part number from the casing of the motor? What color are the three wires (im guessing red, black and white or yellow)? If the third wire is a brake, you'll need to disengage the brake before operating the motor. If you cannot find the manufacturer or part number, you can try calling the repair department of the local dealership for the make of vehicle you aquired this from and give them the model and year number and ask them for a part number.

paysonbadboy

I've worked on lots of cars growing up. Never seen a "brake" on them motors. Usually just two wires and a DPDT switch reverses polarity on one direction that's all.
Same as window motors. Just the fact that the motors are using such a amount of gear reduction would not require any brake to hold in position.

Just guessing, but those motors probably spike 40 amps on start up and probably pull 10 amps running. Using something to switch the motor would have to be pretty robust!
Unless you use a good ol' relay.

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Mark G

Three wires on motor.... You may have what is called a CAN - LIN· interface.·· Controller Area Network - Local Interconnnect Network.....

http://www.interfacebus.com/Design_Connector_LIN_Bus.html


Auto makers are migrating toward using a 3 wire (Power, com and GND)·serial communication network to interconnect controls and sensors.··This minimizes and simplifies wiring·accessories by sending control signals over a common·serial network rather than direct point to point wiring of switches.

As a result you need not only a physical interface for the LIN specification such as a Motorola MC33399 but also need to have the proper address and control codes to·communicate with the device.·· (The device could be an actuator or a sensor·)

A clue to weather this is so is the end application .·· A seat motor in a vehicle which remembers seat position and stores presets is more likely to be a LIN enabled device vs a vehicle which uses just a switch to move the seat.

·

paysonbadboy

Never thought of the programmable seats :-P
Would it actually have all that inside the motor or just send pulses back to the seat control to "count" it's movements and memory? Interesting.

I've got my '03 Dodge 4X4 which I plan on keeping even when it's paid off. It's so easy to take apart that I mod things for the heck of it. Only motors in it are the windows and the other usual stuff.

Our '04 Dodge Grand Caravan has motorized everything which will be the vehicle we keep trading in after each few years because I know that stuff will break and it's no fun to take apart like my truck is.
Got motorized side doors, rear hatch, driver seat, and the foot pedals. But the seat and pedals have no memory. Just switches.
Still, the wife generally drives that and it's a lazy persons ride. Hit a button and any of three doors will open or close fully.

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Mark G

Typically a master microcontroller handles the "memory" functionality of seat position. The master sends commands to the slave device (up to 16 on a LIN ) such as fwd, rev, rate. The slave has a controller as well which interprets the commands. The problem with working with an undocumented LIN device is determining what the adress and command codes are and what capabilities of the LIN device can perform.

Some LIN devices go into a diagnostic mode when a Master is not detected within a few seconds. For a sensor this would mean that it would output a PWM signal instead of a LIN protocol serial output. A dewpoint sensor which sends Temperature, Relative Humidity & Dew point info over LIN will transmit the Dewpoint as a 10% to 90% Pulse Width Modulated output.

An Actuator might require a trigger to go into diagnostic mode. (You would want the seat of mirror to move just because communication was lost with the master)
This could mean holding the signal wire (third wire) at Hi, lo or 50% for 10 - 20 seconds or so with a pull Up/Down resistor to enter diag mode and activate the motor for example. A service manual and schematic for the seat might give you a clue.

Jim Forkin

For some information, schematics, parts selection, software to control DC motors with the stamps, pc boards, etc. check out this web site
http://www.geocities.com/jimforkin2003/index.html