I'm gearing up to start on a new Project with my schools race team and I think I have everything figured out but I'm super nervous about being sure that I figured everything out! I want to be able to run an adruino on the car and using a xbee send the data back to the pc for live monitoring, I also want to use the spark fun can bus shield to get ecu data, and 4 tire temparature sensors to measure, well temparature. I was also going to use the em506 gps module to get the gps position. and If it is possible I really want to have a live dash on the car but I understand that might be out of reach. I am so new to this device and very excited, we want to order everything soon! thanks for your help!
I don't think the Xbee over the air protocol is suitable for various technical reasons.
Instead buy a radio controlled transmitter used for model aircraft that has 8+ channels and buddy box interface. Put that in the car and send the telemetry through that using an Arduino as an interface between the sensors/CAN bus and the buddy box.
At the receiving end you'll need a corresponding receiver and an Arduino to turn the PWM outputs into numbers.
Thank you so much for your response sir. I am not very familiar with the method of communication do you have any documentation on this method of communication? It would be very helpful thanks chris.
Perhaps post a question here
https://www.rcgroups.com/radios-135/
explaining that you need to send multiple channels of data in real-time using an Arduino instead of using the joysticks and switches on the transmitter.
Thank you for all of your help!
You will still end up with your data serialized, but that is not really going to end up as a big issue. don't get tied up in trying to turn an arduino into a mainframe computer. You can use multiple nodes of arduinos to complete all your desired tasks and report to one or two main units for datum display and transmission.
Unless you need to see the data in real time, consider just logging all the data to an SD card for later analysis.
Much simpler approach!
chrisjohnson7690:
I'm gearing up to start on a new Project with my schools race team and I think I have everything figured out but I'm super nervous about being sure that I figured everything out! I want to be able to run an adruino on the car and using a xbee send the data back to the pc for live monitoring, I also want to use the spark fun can bus shield to get ecu data, and 4 tire temparature sensors to measure, well temparature. I was also going to use the em506 gps module to get the gps position. and If it is possible I really want to have a live dash on the car but I understand that might be out of reach. I am so new to this device and very excited, we want to order everything soon! thanks for your help!
I cannot see how anyone could advise on the communications, you have not provided any clues at all about the terain and distances involved.
Apart from that, your project is clearly in the 'advanced' category so you might want to also give us a clue as to your level of experience in electronics, coding and construction.
Here's some info about the Spektrum brand which uses spread spectrum transmitters. Other brands of RC transmitters use spread spectrum, frequency hopping or a combination of both.
https://www.spektrumrc.com/ProdInfo/Files/Remote%20Receiver%20Interfacing%20Rev%20A.pdf
"In normal operation, the Spektrum remotes issue a 16-byte data packet every 11ms or 22ms, depending
upon the selected protocol. ". This corresponds to 1454 or 727 bytes per second.
My own experiments with Xbee under ideal conditions gave 2500 bytes per second. Xbee uses a bidirectional acknowledgement and delay-retry algorithm which will foil attempts at real-time data transmission when reception conditions are poor. I don't know enough about the nRF24L01 to make any comparisons. Perhaps someone else can comment.
I would like to thank everyone for your help. To clear up a couple of points yes the goal of my project is to get data in real time,However we might have the functionality of not having a live mode this would download the log data. Tt will also exclusively be used in a open parking lot with no or little elevation change. A concern of mine is the ability for a signal to stay locked onto the car when in motion, the car will reach speeds in acess of 30-50mph, and that will fluctuate heavily. Thank you!
mikb55:
I don't think the Xbee over the air protocol is suitable for various technical reasons.Instead buy a radio controlled transmitter used for model aircraft
I'm curious and I'm always suspicious of "various technical reasons". In what way is the RC transmitter better that an XBee?
If the 2.4GHz transmissions of an RC transmitter are adequate then a much cheaper and more flexible way would be to use a pair of nRF24L01+ transceivers - probably the high-power variety with the external antennas. Then there won't be any messing about converting data to pulse widths and back again.
If a lower frequency system would be better there have been good reports in other Forum Threads about the HC-12 modules - but I have no personal experience of them.
Robin2:
I'm curious and I'm always suspicious of "various technical reasons". In what way is the RC transmitter better that an XBee?
RC over the air protocols are optimised for real-time and interference resistance. Some data loss is expected and there is no attempt to retransmit lost data.
The Xbee protocol is optimised for reliable delivery of every packet. After every failed packet it uses a delay-retry algorithm to make repeated attempts to send the data again. While this is going on your RC plane isn't receiving any data and will lose control unless it has some kind of autopilot fallback control.
The RC transmitter world is highly competitive. There is no requirement to maintain compatibility with standards or prior generations therefore manufacturers are free to innovate using the latest in consumer grade spread spectrum and frequency hopping technology.
Here's 179 RC planes flying at the same time using the 2.4 GHz band.
