Couple of questions about Jeenode v4.

Can anyone who has used one or has one (set) give an estimate on range?

With only 4 digital outs, are they normally used in tandem with another arduino, and can the digital pins on the one you decide to use for the Controller be used for indicator lights, or can only the pins on the reciever be used?

It comes “ready to interface with arduino” but also says a USB-BUB is needed to program it. Does that mean that I need one to just mess around with it and learn, or is that for more advanced applications?

Thanks.

You can't program it without an other device, it says:-

The USB communication interface has been removed and any USB-to-TTLSerial based on the FTDI232R chip is guaranteed to work as connection.

So you need something like a break out board that converts USB to serial TTL.

With only 4 digital outs,

Why do you say this. This page shows lots:-
http://cafe.jeelabs.net/lab/jn4/

I was going from the info off the Modern Design website since im in US and they are the ones who sell the US mhz. I guess I should have read the labs page a bit more.
http://shop.moderndevice.com/products/jeenode-kit

Specifications
4 ports for A/D, I2C, Digital Output etc
ISM-band 915 Mhz, or 433 MHz radio
Atmega328 chip, and voltage regulator
Shipped with Duemilanove bootloader and JeeNode demo
sketch, ready to send bytes, out of the box.
Programmed with MD USB-BUB or FTDI cable

Thats why I was curious about the USB-BUB. I went ahead and ordered one anyway because they were cheap, but it infers that it is shipped ready to "communicate."

If you are bored and want to explain the difference between A/D, I2C, and digital ports are, feel free :slight_smile:

A/D - analogue to digital converter built into the processor chip. Feed a voltage 0 to 5V in get a reading 0 to 1023 out.

I2C - Pronounced "eye squared cee" is a two wire bus you can hang lots of other chips from, it stands for "Inter integrated Circuit" bus and is used for chips to talk to each other.

Digital port - can be an input or an output as you wish. Single logic level high (5V) or low (0v) output or input.

Awesome, thank you very much. Now I have a new amazon keyword to search for " I2C" :wink:

As for the A/D, does my duemilanove or uno have that capability, since you can divide analog val by 4, or does it mean it has a built in function that does it automatically?

If you recall I was asking about op amps for a 49mhz r/c recently to amplify the signal, and having a yard full of cars and parts, found that two radio antennas soldered to the ant terminals increased the range rather extraordinarily. I get the feeling you would already know something like that, but it was very exciting for me ;D Still bought the Jeenodes though, seems like I can learn a lot more by constructing the set rather than buying a ready made R/C unit. Thanks for the answers, you really aren't near as grumpy as they say but I won't tell.

does my duemilanove or uno have that capability,

Yes they have 6 inputs that can be used as A/D inputs. Dividing by 4 just brings the range down to 0 - 255 not sure why you would want to do that.

found that two radio antennas soldered to the ant terminals increased the range rather extraordinarily

That would only be the case if the antennas were poorly designed in the first place. Basically you have to get a half or quarter of a wavelength and then match the impedance of the antenna to the impedance of the output stage of the transmitter. However most RC car's transmitters are not very well designed. On a badly designed system you can even get improvement by shortening the antenna.

Yes they have 6 inputs that can be used as A/D inputs. Dividing by 4 just brings the range down to 0 - 255 not sure why you would want to do that.

One of the "example" projects has you use analogwrite and dividing the value of the analog input by 4 and using it for PWM if I understood it correctly.You are the second or third person to comment on this though, so either something in my understanding is off, or there is now a better way (the examples dont even get into libraries) to do the code from the example.

If not using analogwrite, what happens if you enter a value greater than zero and less than 255 on a digital pin? does it have a threshold voltage/number that triggers high or does it have to be pure 5v?

That would only be the case if the antennas were poorly designed in the first place. Basically you have to get a half or quarter of a wavelength and then match the impedance of the antenna to the impedance of the output stage of the transmitter. However most RC car's transmitters are not very well designed. On a badly designed system you can even get improvement by shortening the antenna.

Very Good. I love finding out why something did or did not work. The antenna was just a tiny piece of wire that wasn't even really making contact with the board. I should probably preface anything I ask about implementing existing things with the arduino by saying " this thing is a complete piece of junk that I either got for free or less than 10 quid.

Im a bit of a hoarder but I find I can throw things away after I take them apart and remove any worthwhile pieces.. Which I then hoard :stuck_out_tongue:

what happens if you enter a value greater than zero and less than 255 on a digital pin?

Zero would write a LOW and anything else would write a HIGH.

I don’t recall anyone else ever asking that question (or anyone answering it, either) You could do the experiment to find out, but it seems like the wrong question, IMHO. If one were writing code that sloppy, then they should try writing cleaner code and not depending on those kinds of undocumented features.

Richard, I have a feeling if i spent an hour with you, I would literally drive you crazy with questions you don’t feel are very pertinent. I am not an engineer, though I was halfway to a Mech. Engineering degree at UT-Knoxville before the entrepreneurial gene kicked it and I left to start a business. I drove most of my professors crazy with questions they did not feel were pertinent.

As a general rule, If i have a specific question on how to make certain components I want to use work, I will give all the details and what I have tried so far. When I ask a very vague question like that one was, It’s because I am trying to understand how all the parts of a whole work together, not because I want to use it in code. I know it drives a LOT of engineering types crazy (we were separated into groups for projects based on Meyers- Briggs personality test results, I am an ENTP, the only one out of over 500 students in the program, and the ‘rarest’ type according to the information they gave us.)

I was actually going to test it until Grumpy Mike chimed in :wink:

Thanks for the explanation on analogread/write

Zero would write a LOW and anything else would write a HIGH.

Thanks.