Radio Problems!! Please help

[dez250]

here if you want you can buy the stamper and accessories here, but please only purchase these items if they are going to be put to proper use, as they can cause interferance with other products...

http://www.electrowave.com/products/stamper.shtml

[arpus maximus]

Originally Posted by Andy A.

Secondly. You mentioned that the low battery light is on. If this light is one when you are teatherd, then your RC is probably not getting enough power either. That light comes on when the RC's voltmeter drops to a certain level. This value can be changed int he program, but I think it defaults to 10 volts. Usally this doesn't cause radio problems, but I have noticed it can crop up when using a very old battery or if there is a bad connection between the RC and the battery. How is the RC being powered? Did you end up powering through the cars 12volt system? Did you ever check the quality of that power? It may not be adequate. If this is the case, then your RC radio may not be fully powered, which could result in the same symptom. Check the voltage at the RC's power terminals with a voltmeter. It should read right around 12v, give or take 2.

-Andy A.

Our original setup:
* OI plugged into wall via 9V AC Adapter (the amperage was NOT 1500mA, i believe it was lower)
* RC hooked up to 12V battery by running 18-gauge copper wire from the battery's terminals to the contact points on the RC
* RS-422 Screamer Tx hooked up to OI via DB9 cable
* RS-422 Screamer Rx hooked up to RC via DB9 cable
* Joystick in port 1 on the OI
* RC hooked to computer for program download via DB9

When we did this, the radios both had the "standby" LED lit up and there did not seem to be any transmission. "Valid Rx" was not lit up, and the "No radio modem" led was blinking, i believe (i dont have the materials in front of me right now). In any case, the radios were not getting any sort of signal.

The transmitter's antenna IS broken (read: snapped off) about half way up. I assume this will have adverse effects on the range and reliability, but I would assume it would still be able to communicate with a receiver that is only 2 feet away and in direct line of sight. Perhaps not?

To answer a few questions:

We were originally going to power the RC through the car's battery, but when we plugged it in, it continually turned on, then shut off, then turned on, then shut off, etc. Obviously, this was unacceptable, so we are going to power it with a separate 12V battery that seems to power it well. With this set up (and using a tether) we can operate motors and the such nicely!

I am not on a team and never was on one, believe it or not. Everything I know about robots and control systems and the sort (that is, not much) I picked up in the last week. We borrowed the equipment from team 571 which is the team at our school, Team Paragon at Loomis Chaffee in Connecticut.

And, finally, an update:

We located the gas cable which, we found, was much harder to cut than expected. But, after a lot of using wire cutters and pulling (we even used pruning loppers and an electric drill!) we finally cut the resilient cable and hooked it up to our servo. We mounted the servo more-or-less securely under the hood and hooked it into the RC. Using a tether, we were able to pull the throttle cable and rev the engine by tilting the joystick forward! Very exciting! Clearly, we will not take the car out of the garage until all systems are working (and the radio problems are solved). Still, it is somehow very gratifying to rev the engine with a joystick!

ARP

[Andy A.]

Originally Posted by arpus maximus

Our original setup:
* OI plugged into wall via 9V AC Adapter (the amperage was NOT 1500mA, i believe it was lower)
* RC hooked up to 12V battery by running 18-gauge copper wire from the battery's terminals to the contact points on the RC

This is probably the problem. Try to find a fully rated adapter, probably from your schools team. They should have a few, a new one comes in the kit every year and they have been the same since 2000.

Originally Posted by arpus maximus

The transmitter's antenna IS broken (read: snapped off) about half way up. I assume this will have adverse effects on the range and reliability, but I would assume it would still be able to communicate with a receiver that is only 2 feet away and in direct line of sight. Perhaps not?

Radio attenas are funny things. I don't pretend to understand them, but my expeince has led me to assume that if looks broke, it is broke. You can get replacement attenas, the broken one should screw out. The chances of buying a new one are pretty slim, but maybe you could find something that would work. Again, check with your team if the new power supply doesn't fix things up. All the attenas should be the same from year to year, so perhaps you could borrow one.

Originally Posted by arpus maximus

Using a tether, we were able to pull the throttle cable and rev the engine by tilting the joystick forward! Very exciting! Clearly, we will not take the car out of the garage until all systems are working (and the radio problems are solved). Still, it is somehow very gratifying to rev the engine with a joystick!

ARP

Sounds very cool. Glad to hear things are coming along.

-Andy A.

[arpus maximus]

Update!

Today we were able to get the radios working thanks to the original AC adaptor being put to use. Theyre communicating nicely, and we've got the throttle of the car under total remote control. Thank you for all the help on the radio issue!

[dez250]

congratulations and good luck with your project, please keep us updated.

[Gamer930]

Yes congratulations. This seems like a very interesting project/adventure. I think many of us would be interested in pictures :-)

[Astronouth7303]

Sounds like a team number problem. on the 04's, this is set on the RC using tether.

[Greg Needel]

Originally Posted by Astronouth7303

Sounds like a team number problem. on the 04's, this is set on the RC using tether.

true but they are using a 2001 system.....and it turned out it was the power supply

[arpus maximus]

More updates!

We got the steering working! We were originally going to use a van door motor and a pulley system with a belt to turn the wheel, but soon found that it was impossible to make the belt tight enough, and it would not grip. We scrapped the idea of using a sprocket and a chain because we've heard that chains are fidgety and no good most of the time (unless they're set up very precisely). So, instead we removed the steering wheel, which revealed a threaded bolt. We screwed on a threaded connector and attached the van door motor's axel directly do this threaded connector. With this setup, obviously the motor would just spin around rather than spinning the wheel, so we made a brace for the motor to keep it from spinning. Lo and behold, it turns the wheel like magic!

The brake system hit an unexpected snag today... potentiometers are far beyond me and, for the scope and time constraints of this project, are too difficult to use. So, instead of holding back on the joystick be the brakes, we will have the trigger engage the brakes and the top button disengage them. This is not exactly the most desirable setup, but it is the best and most efficient way to do what we need to do.

The brake setup uses a power window motor with a sprocket welded to the axel. We then mounted a sliding drawer rack and secured a chain to the top. When the gear spins, it pushes the rack into the brake pedal, slamming the brakes. However, the gear slips a LOT so we will have to put pressure down on it to prevent it from slipping. Either that, or use an entirely different idea. We have a week left, and we are far ahead of schedule, so anythig is possible.

ARP