SparkFun Forums

[Streamtracker]

I am using an Adafruit Ultimate GPS Breakout (66 channel w/10 Hz updates - MTK3339 chipset) unit and mounting it to a ski helmet. The arduino is is going to be either in a backpack or fannypack. In either case there will be a cable run of several feet between the GPS module and the arduino.

I am putting the GPS module on the helmet to assure it pointing up. Maybe I don't need to do that and it will work fine in the either pack. But, I think I will get a more reliable signal from a helmet mount.

Any advice on this? It's a serial connection via the tx and rx ports. Do I need to worry about noise in the line if it is up to 3 ft. long? If so how can I design for it?

Thanks!

[fll-freak]

Without a link to the specific unit you are interested in, I can only answer in generalities. If the output of the GPS module is RS-232 voltage levels, then 3 feet is not going to be a problem. With good shielded cable 100 feet would work. If the output of the GPS module is 5V or 3.3V serial than 3 feet may or may not work. You could try using a length of 9 pin shielded RS232 cable. If that does not work, then putting an RS-232 level converter on each end of the cable to boost the signal voltage would be a fall back solution.

[Streamtracker]

fll-freak thanks for the reply.

Here's the link to the product: https://www.adafruit.com/products/746

It is 5 volt level.

[fll-freak]

Although I do not have any person experience, I would image that in a non noisy environment a few feet from the helmet to a backback of good quality shielded cable of sufficient gauge wire should work. I would not expect it to work near motors, power lines or other noisy sources.

[Polux rsv]

GPS modules don't like vibrations. Signal reception is affected, even if the antenna is pointing up. I had this problem on a race motorbike. The GPS module was fixed with welcro. Moving it to the tail and fixing it with bolts solved the problem.

Angelo