RS232 --> Bluetooth. What do you think ?

This is a forum for discussing the development and testing of alpha MS2/Extra code. Documentation
(Runs on MS2 and Microsquirt)

Moderators: jsmcortina, muythaibxr

piledriver
Super MS/Extra'er
Posts: 1679
Joined: Tue Oct 27, 2009 6:24 am
Location: Van Alstyne, Texas

Re: RS232 --> Bluetooth. What do you think ?

Post by piledriver »

The MAX232 and the BT adapter would have to be able to share the comm lines off the CPU.
(Those cheap BT adapters are LVTTL 3.3v, so CPU side)
That's (potentally) the main issue, powering off the BT is trivial.

I have not tried it, maybe it's NOT an issue, but it's something to carefully research and watch for as I would not want to toast a $90-200 CPU for a $7 BT card.
The $50 RS232 class1 BT units are ~plug and play after a simple one time config session with any terminal program, and work fine on the end of an extension cable FWIW.

Hopefully the fellow on EBay is a lister... it IS a neat product/service and he must have done some research.

On close reading he seems to have it figured out.

BTW, I have flashed FW over BT as a test many times. No issues. (MS2extra V3whateveritistoday) but it is a class1 BT unit.

I like the external as the MS units seems to be breeding, somehow I have 3 now...
Always doing things the hard way, MS2 sequential w/ v1.01 mainboard, LS2 coils. 80 mile/day commuter status.
Bean Bandit
MS/Extra Newbie
Posts: 30
Joined: Sat Jan 16, 2010 1:31 pm
Location: Earth, currently middle east and europe

Re: RS232 --> Bluetooth. What do you think ?

Post by Bean Bandit »

I'm a bit at a loss right now... basically what I intend to do is building this http://www.sparkfun.com/products/8495 myself with the module that allows an antenna. The BT module I linked to should work with 3.3-6V according to the specsheet and the shifter SMD will take whatever you throw at it?
I will post some schematics of what goes on in my mind later... got a bit of a blockage right now.
piledriver
Super MS/Extra'er
Posts: 1679
Joined: Tue Oct 27, 2009 6:24 am
Location: Van Alstyne, Texas

Re: RS232 --> Bluetooth. What do you think ?

Post by piledriver »

You realize you can buy one like I have with an antenna for ~$55 US or thereabouts.
Sparkfun has neat stuff, but they are not cheap, not the only source for this stuff.

I bought mine direct from US Converters.

Don't hate on a "chip" antenna, there's a LOT more to it. :lol:
I have the lousy integrated "chip" antenna and have well over 100ft/33m range.
(I haven't tested it further, but I can log my car from my desk with the car WAY out back on the other side of the house...)
Range simply isn't much of an issue with class1 BT devices on both ends.

I still get about 50 feet logging with my cell phone. (class2 BT IIRC) laptop gets 100 with the class1 ASUS USB nub.
(also with a chip antenna, it barely sticks out of a USB port)
Always doing things the hard way, MS2 sequential w/ v1.01 mainboard, LS2 coils. 80 mile/day commuter status.
Bean Bandit
MS/Extra Newbie
Posts: 30
Joined: Sat Jan 16, 2010 1:31 pm
Location: Earth, currently middle east and europe

Re: RS232 --> Bluetooth. What do you think ?

Post by Bean Bandit »

I like to thinker a bit and I'm sure I'll be able to get a better signal with the antenna version than chip, sole because I have some good spare ones at hand.

So you think my setup should work - would I need to be able to disconnect the two models from the DB9 pins completely or is it enough when I just switch the power off with the jumper to use the cable?
piledriver
Super MS/Extra'er
Posts: 1679
Joined: Tue Oct 27, 2009 6:24 am
Location: Van Alstyne, Texas

Re: RS232 --> Bluetooth. What do you think ?

Post by piledriver »

If you want to spend more money to get the ~same parts in kit form, knock yourself out.
Would make more sense to take apart and reassemble :lol:
IME little dipoles are no better than the printed antenna arrays, and sometimes worse..

The antenna equipped versions I mentioned have a SMA connector so you can use whatever antenna you like, and were ~$50 including shipping and another spare dipole.
Always doing things the hard way, MS2 sequential w/ v1.01 mainboard, LS2 coils. 80 mile/day commuter status.
racingmini_mtl
Super MS/Extra'er
Posts: 9128
Joined: Sun May 02, 2004 6:51 am
Location: Quebec, Canada
Contact:

Re: RS232 --> Bluetooth. What do you think ?

Post by racingmini_mtl »

You can't use a 3.3V device without some sort of voltage converter and a 3.3V supply. The MS CPU (all of them) works at 5V.

Jean
jbperf.com Main site . . . . . . . . . . . . . . . . . . . . . . jbperf.com Forum
Image
Bean Bandit
MS/Extra Newbie
Posts: 30
Joined: Sat Jan 16, 2010 1:31 pm
Location: Earth, currently middle east and europe

Re: RS232 --> Bluetooth. What do you think ?

Post by Bean Bandit »

racingmini_mtl wrote:You can't use a 3.3V device without some sort of voltage converter and a 3.3V supply. The MS CPU (all of them) works at 5V.

Jean
Is this directed at me? according to the datasheet the ones I linked to will run any power from 3.3-6V - so this should be ok I assume?

just to be sure: if I remove the jumper (5V from pin 9) can I leave the rest of the connections intact or would it cause some havoc when using the cable?

based on those shematics: shifter and SMiRF would connecting like this work?

Code: Select all

DB9-(Tx)pin2  -> shifter(RS-IN)pin3  - shifter(Tx)pin3  -> BT(Rx)pin5
DB9-(Rx)pin3  -> shifter(RS-OUT)pin2 - shifter(Rx)pin4  -> BT(Tx)pin4
DB9-(Gnd)pin5 -> shifter(Gnd)pin5    - shifter(Gnd)pin2 -> BT(Gnd)pin3
DB9-(Vcc)pin9 -> shifter(Vcc)pin9    - shifter(Vcc)pin1 -> BT(Vcc)pin2
piledriver wrote:If you want to spend more money to get the ~same parts in kit form, knock yourself out.
Would make more sense to take apart and reassemble :lol:
IME little dipoles are no better than the printed antenna arrays, and sometimes worse..

The antenna equipped versions I mentioned have a SMA connector so you can use whatever antenna you like, and were ~$50 including shipping and another spare dipole.
unfortunately the antennas I have around are RP-SMA so not much use on the USconverters...
oh well I'll sleep about it and see what I end up with :)
racingmini_mtl
Super MS/Extra'er
Posts: 9128
Joined: Sun May 02, 2004 6:51 am
Location: Quebec, Canada
Contact:

Re: RS232 --> Bluetooth. What do you think ?

Post by racingmini_mtl »

Bean Bandit wrote:Is this directed at me? according to the datasheet the ones I linked to will run any power from 3.3-6V - so this should be ok I assume?
It's addressed to anyone using a device that connects to the CPU.

And power is one thing but it also have to have I/Os that are 5V or at the very least 5V compatible.

Jean
jbperf.com Main site . . . . . . . . . . . . . . . . . . . . . . jbperf.com Forum
Image
Bean Bandit
MS/Extra Newbie
Posts: 30
Joined: Sat Jan 16, 2010 1:31 pm
Location: Earth, currently middle east and europe

Re: RS232 --> Bluetooth. What do you think ?

Post by Bean Bandit »

racingmini_mtl wrote:
Bean Bandit wrote:Is this directed at me? according to the datasheet the ones I linked to will run any power from 3.3-6V - so this should be ok I assume?
It's addressed to anyone using a device that connects to the CPU.

And power is one thing but it also have to have I/Os that are 5V or at the very least 5V compatible.

Jean
so would the device I linked to work? This discussion is starting to go beyond my knowledge/understanding quite quickly.
racingmini_mtl
Super MS/Extra'er
Posts: 9128
Joined: Sun May 02, 2004 6:51 am
Location: Quebec, Canada
Contact:

Re: RS232 --> Bluetooth. What do you think ?

Post by racingmini_mtl »

Just read the page on Sparkfun (the part I've put in bold):
Sparkfun wrote:The remote unit can be powered from 3.3V up to 6V for easy battery attachment. All signal pins on the remote unit are 3V-6V tolerant. No level shifting is required.
Jean

EDIT: This is very basic stuff when planning such a task. If it's more than you can handle then you should look at ready-made solutions or read and learn more. No offense intended.
jbperf.com Main site . . . . . . . . . . . . . . . . . . . . . . jbperf.com Forum
Image
Bean Bandit
MS/Extra Newbie
Posts: 30
Joined: Sat Jan 16, 2010 1:31 pm
Location: Earth, currently middle east and europe

Re: RS232 --> Bluetooth. What do you think ?

Post by Bean Bandit »

racingmini_mtl wrote:Just read the page on Sparkfun (the part I've put in bold):
Sparkfun wrote:The remote unit can be powered from 3.3V up to 6V for easy battery attachment. All signal pins on the remote unit are 3V-6V tolerant. No level shifting is required.
Jean

EDIT: This is very basic stuff when planning such a task. If it's more than you can handle then you should look at ready-made solutions or read and learn more. No offense intended.
so I guess my idea is good to go then :) any input on the above wiring and concern regarding any side effects when kept in place?

Best regards Baen
Bean Bandit
MS/Extra Newbie
Posts: 30
Joined: Sat Jan 16, 2010 1:31 pm
Location: Earth, currently middle east and europe

Re: RS232 --> Bluetooth. What do you think ?

Post by Bean Bandit »

made a slightly nicer drawing - can anyone confirm if this is right? I don't know much about these things :oops:
:?: can I leave all the wiring in place and simply disconnect the power to the MS DB9 when I intend to use the regular cable?
BT module wiring.JPG
PS: to have it all together here are the links to the schematics of the two modules: RS232 shifter and BlueSMiRF

Thanks for any help

Bean
Post Reply