rf remote control / in-car

[malofquISt]

I want to make an RF remote control that tranmits from my steering wheel to a reciever under the dash to shift the transmission. I need to be able to shift at maxx.. 5/10 times per second, but I need to send up/downshift commands that are secure, no bit errors!

microchip makes cool rfmcus for this, but they can't 'shift' fast enough for me,

any suggestions?

thanks,

OM

 

[melone]

5 - 10 times per second?! What is the final application?

 

[malofquISt]

the finished product is to shift the car's transmission. two wireless butotns on the steering wheel that sends an 'up' and 'down' command to a receiver wired to the transmission. if you come to a stop in 4th gear and want to quickly press-press-press down to 1st you's want those three quick presses to happen in less than a second. the microchip RF eval board does not allow that at all. it would be press-wait 1sec- press-wait 1sec-press-wait 1sec.

 

[WoodrowJWeen]

As a matter of fact, yesterday in the local electronics I saw that somebody already makes such a thing for use in controlling aftermarket car stereos from the steeing wheel. Can't remember who made it but this was in Best Buys. I'm guessing Circuit City or Hi-Fi Buys has similar equipment.

 

[MacGyverS2000]

Those are generally based upon measuring resistance changes, and I would DEFINITELY not want such a simplistic device shifting my transmission.

 

[malofquISt]

thanks for input....

a friend of mine is starting his own company called PCS (powertrain control solutions)

http://www.transmissioncontroller.com

he is the one who needs this product. i am just trying to help out with infrared or RF option to fit any car, with one or ten wires leaving steering wheel.

(unless I misunderstood your 'running a wire from ign. switch')--I can not pull power into the steering wheel from ignition switch, the turning of the wheel would break any wire 'ran' into it.

we've ordered samples of steering wheel mounted buttons and they can respond to i'ferance, or won't send outputs out fast enough.

you have an excellent point about battery powered switches, we'd need to output battery status, and throw a red light when battery gets below certain threshold!

the existing horn wire in every car can be used to power whatever circuit we come up with, eliminating the need for separate battery... but is this is for a product to be sold, needs to have instructions that people can follow....

Mark

 

[malofquISt]

I'm still looking for a safe and secure way to wirelessly shift the transmission from a sterring wheel.

anyone out there?



Mark

 

[VEBill]

There are several (typically expensive) cars that have steering wheel mounted paddle shifters - have you investigated how this feature is done in those vehicles?

There are LOTS of (even very cheap) vehicles that have various switches on the steering wheel (for radio and display control).

I'm fairly sure that none of these systems would use RF. They most likely use slip rings, or perhaps have wires that can twist reliably for the life span of the car.

Probably using the CAN bus.

 

[richs]

Hi-

Just a suggestion. You might be able to pull power
from the horn switch on the steering wheel. A low
power drain from the switch most likely will not cause
the horn relay to close. Storing the charge received
from the horn in a super cap (so your controller doesn't
loose power when they blow the horn) would be something
to consider.

It would not need a power consuming LED to light when
the person is interested in checking for power to the
device. All he/she would have to do to test it would
be to blow the horn!

Of course, this is the good old fashioned car that we
are talking about. Nowadays, they might have a
controller in the steering wheel which has power and
data passed through the steering wheel to account for
say, the horn and the air bags. So, with this in mind,
YMMV. Hope that this helps!

Cheers,

Rich S.

 

[Yashu]

Bluetooth is hot. Using BCSP instead of HCI should help.

Like they say, you want something done "right", do it yourself. Reliability = redundancy. Code it all yourself according to what YOU want.

 

[buzzp]

Atmel chips have instruction cycles that are typically 1/4 that of Microchip, if speed is an issue (can't imagine it would be with only 5-10 switches in a second). Also they have math commands in their low end stuff which microchip does not have.

Power is easily found in a steering wheel. Think where most ignition switches are along with blinkers and steering wheel controls. I can't not imagine lack of power at the steering wheel presenting a problem. Now if you were talking about a hard wired system, I could see this presenting a problem but you want wireless so it should not be an issue.

 

[legalimit]

If you are going to power the unit from the horn button, then you might like to consider modulating the current you draw and sensing the current change at the horn, or its relay

 

[EEcarl]

Im not sure I would buy a wireless or RF controller. If I were in the market for a steering wheel transmission shifter I would want it to be wired, probably CAN bus. An IR will need line of sight, and it is likely you will obstruct the transmitter at times.