Hi,
I made 433MHz RC control car, few questions, sorry its too mess to upload some thing, just see if some one has the same experience:

1. the car has an action lag when pushed the control joystick;
2. heard may need a malfunction Emergency stop, just wonder how? software ? or maybe put another Arduino to oversee it?
3. any better idea about hand hold unit battery, need 7-12 V, small size and long last.

Thanks

 

A second arduino is not a good option if you wantbenergy efficiency. With 1 arduino it should last about annhour with a 170mA/h 9V battery. Use a 18650 battery which is 2500mA/h.

Without a circuit or somethimg it will be very hard for anyone without direct experience to help you.

 

What would be valuable is an arrangement to switch off the car drive power if the carrier is lost at the receiver. So your controls receiver needs a carrier detect output. The delay in response is the sum of all the delays in the system and so there are a number of possible causes. And for how to deal with the battery, most radio control systems put it in the same package with the transmitter.

 

What would be valuable is an arrangement to switch off the car drive power if the carrier is lost at the receiver. So your controls receiver needs a carrier detect output. The delay in response is the sum of all the delays in the system and so there are a number of possible causes. And for how to deal with the battery, most radio control systems put it in the same package with the transmitter.

Thank you.
Are there any carrier detector for sale?
How about if the main control unit say Arduino lost function, and the car keep running?

 

Thank you.
Are there any carrier detector for sale?
How about if the main control unit say Arduino lost function, and the car keep running?

A carrier detect circuit is a small bit usually added to a receiver circuit. I have never seen one as a separate part. The circuit works in a manner similar to the squelch circuit, except that it controls something exterior to the receiver. Did you design the receiver that controls the car, or did you buy one?

 

1. the car has an action lag when pushed the control joystick

Is the delay in the Transmitter, in the Receiver or both?
Interference?

2. heard may need a malfunction Emergency stop, just wonder how? software ? or maybe put another Arduino to oversee it?

a) Carrier Loss
b) Emergency Stop Button on transmitter triggers the Emergency Stop System on the car

3. any better idea about hand hold unit battery, need 7-12 V, small size and long last.
Thanks

a) Li-Ion Batteries connected in series

 

What you're looking for is called a "fail safe" in the RC world. Typically when the receiver looses signal, the fail safe will put on the brakes, or just turn the motor off, depending on how you have it set up. Some examples:

https://www.amainhobbies.com/fail-safes-electronics-cars-trucks/c1834

 

Like I said in an earlier post, except that examples are the remote control for industrial overhead gantry cranes and the remote controls for the winches on bigger tow trucks. If for whatever reason the receiver stops hearing the transmitter the control system stops everything. Thus any failure anywhere shuts it down. That is why it is called "fail safe". Actually it is "fail and fall dead", but that does not sound as cool.

This is totally different from that big red button on some cars now, which the button just sends a signal to the engine controller requesting a shut down. But if the throttle sticks the computer will not switch off the engine because it has decided that you will need power steering assist as you are going 85MPH.

 

A carrier detect circuit is a small bit usually added to a receiver circuit. I have never seen one as a separate part. The circuit works in a manner similar to the squelch circuit, except that it controls something exterior to the receiver. Did you design the receiver that controls the car, or did you buy one?

Thank you.
some RC module seems build in that function?
https://infocenter.nordicsemi.com/pdf/nwp_001.pdf

I built my receiver and looking for a simple carrier detect circuit to add in.

Is the delay in the Transmitter, in the Receiver or both?
Interference?


a) Carrier Loss
b) Emergency Stop Button on transmitter triggers the Emergency Stop System on the car


a) Li-Ion Batteries connected in series

I used 3 pieces of 3.6V NI-MH rechargeable batteries, no last a long time.

Like I said in an earlier post, except that examples are the remote control for industrial overhead gantry cranes and the remote controls for the winches on bigger tow trucks. If for whatever reason the receiver stops hearing the transmitter the control system stops everything. Thus any failure anywhere shuts it down. That is why it is called "fail safe". Actually it is "fail and fall dead", but that does not sound as cool.

This is totally different from that big red button on some cars now, which the button just sends a signal to the engine controller requesting a shut down. But if the throttle sticks the computer will not switch off the engine because it has decided that you will need power steering assist as you are going 85MPH.

Thank you,
that happened one time the motor keep running after I released the control handle. I don't know why, maybe the signal maintained HIGH?

What you're looking for is called a "fail safe" in the RC world. Typically when the receiver looses signal, the fail safe will put on the brakes, or just turn the motor off, depending on how you have it set up. Some examples:

https://www.amainhobbies.com/fail-safes-electronics-cars-trucks/c1834

Thank you, and I'll check there.

 

What you're looking for is called a "fail safe" in the RC world. Typically when the receiver looses signal, the fail safe will put on the brakes, or just turn the motor off, depending on how you have it set up. Some examples:

https://www.amainhobbies.com/fail-safes-electronics-cars-trucks/c1834

Thank you.
I searched "fail safe" , seems some one made some stuff like : https://www.jaycar.com.au/rc-fail-safe/p/DC1504
just wonder can it works? Is it a general purpose module, or need a specific one for certain application?

 

It looks like it may work. It will control a servo as well as cut power. However, it is discontinued and may not be available for long.

I don’t know where you live (should be on your profile). It appears that this item is only available in Australian Jaycar stores. No shipping available. It doesn’t appear to be available from the Jaycar in the US.

 

It looks like it may work. It will control a servo as well as cut power. However, it is discontinued and may not be available for long.

I don’t know where you live (should be on your profile). It appears that this item is only available in Australian Jaycar stores. No shipping available. It doesn’t appear to be available from the Jaycar in the US.

Thank you.
Seems not easy to get it, but there are many kind of that stuff on EBAY now.
I just hesitate, if it can cut off power in any fails? what I can think of like: Arduino go Infinite loop； some components fail resulted the control PIN HIGH; etc.

 

The description of the item you linked to, explicitly states that power to the device will be cut.

BUT, you bring up an interesting point. That device (and others like it) cut power when THE RC RADIO SIGNAL IS LOST.

An internal failure, such as the code going into an unwanted infinite loop or a component failure leaving an output getting stuck, won’t be detected.

Those conditions must be planned for. It may be that unique fail-safe solutions will be required for each point of failure.

You have to identify each point of failure, identify what might happen in each case and then estimate the probability of that failure happening, Based on that, you may or may not want to protect against that case. Practically, you will not be able to identify all points of failure, but you will identify the major problem areas. Your system is simple (the RC car) so this exercise should be simple.

 

Does your radio module have an RSSI (received signal strength indicator) feature? If yes, you can watch that with your processor, and if the signal drops too low then assume you've lost contact and have the processor do what you think is appropriate. The catch is, you have to be sure your code is solid, if the processor resets, locks up or does anything that it shouldn't then your device may go out of control. So depending on your use case, you may want your fail-safe to be an independent device. But if it's just for fun or learning with no real danger, then let the processor handle it. You can try adding watchdog features to your code or device to reset the processor if it becomes non-responsive.

 

It is unwise to include any processor devices in a fail-safe string because of the probability that a failure will be in the processor device. So the fail safe system needs to switch off the power to all of the circuits that cause any actions whenever the carrier is lost. If the processor system locks up it will usually not respond to an interrupt requesting a shutdown. Besides, if the control transmitter develops a problem the first recourse is to switch it off. That would stop a runaway car.