RadioBoard is a small, standalone low-power capable board (under development!) with some uC and some radio transceiver.
Radio onboard ECM
IMNSHO it is a bad idea to put the radio stuff onboard:
- most people will never need it (but need cable connection)
- a standalone board has 20 times bigger market - even many of our boards are already manufactured without radio - those will want to use it, but thousands (!) of others too
- the onboard placement is bad anyway, because of the antenna connection requirements.
therefore...
Standalone universal radio-modem:
Spending time on a standalone radio modem would be more productive, there is a strong demand for short range radio modems that can replace a rs232 cable. Pretty much like what bluetooth can allready do, but could be done maybe just cheaper.
Simple Radio (modem point-2-point link) - not very flexible; but for just datalogging a racecar, it's often enough.
Decision about connection to the embedded system
See CommMatrix for details.
- UART, RS232: in this case I think it's best to have 2 board (PCB or population) options:
- with MAX232 chip (- / + 8V signal)
- without MAX232: 0 / 3 V signal compatible
- SPI
- I2C
MAX232 can be wiped off anyway - with all those USB -> serial mobile phone cables - often heavily discounted.
I think maybe keeping real 232 is fine after all, because TTL-level RX/TX line can be taken off the board anyway.. It's only difference in price of vems itself, it needs then some USB->serial or serial->serial (both TTL-level FBUS) or similar cable.
Decision about compatibility
- Bluetooth vemsfrontier/bluetooth good for computer to vems connection. Good bluetooth module does not need changes to anything else. Compatible with each other.
- [Zigbee] I always liked this (it was called Berkeley Mica Mote earlier). Chipcon CC1000 radio transceiver on it that is similar to the successful [Mica Mote board] from our friends at Berkeley. It will provide all the hardware capabilities that TakeCareBoard needs.
- Chipcon, Nordic VLSI, not really compatible to anything else.
Bluetooth devices with it's own pcb CAN be made, but it's really 1000 times harder than with zigbee. And I think costs are many many times (in low series) than zigbees. Power consumption of zigbee is also superior (lower), so it's good for anykind of handheld devices as wireless LCD and keyb.
Religional beliefs
If anything has a chance of beeing the standard for short range wireless communication it's bluetooth. A friend mentioned that Apple is including it in all their products from now on, Sony is slowly phasing it in and SonyEricsson includes it everywhere.
Most race teams can find lots of use for something like this. Something that works like bluetooth ("like bluetooth" means support for many devices at a time? or just a point2point link? it makes a difference! ) but with more range. All ranges up to 10m (100m with expensive class1 devices) is covered by bluetooth without any firmware or hardware changes. -Jörgen
Jorgen still doesn't like the idea of making a batch of v3's without RS232. A small addon board could be acceptable, but an off the shelf rs232-bluetooth adapter would work equally well. Maybe we could make our own at an acceptable cost, there is bluetooth modules that you basically hook up to the UART at booth sides of the bluetooth link and it just works. One of the primary objectives when bluetooth was built was to replace a serial cable without having to change any code. Bluetooth is nice and I really hope that it is here to stay.
Zigbee Applications
- Laptop connection thru RS232 or USB tranciever, with USB to RS232 chip wireless connection is just virtual serial port at computer. No changes to tuning programs, but only pure serial wire replace can be done easily with bluetooth also.
- Central locking system, see www.elfa.se OVO3 package, got one already, it's damn small. http://www.elfa.se/elfa-bin/setpage.pl?http://www.elfa.se/elfa/produkter/fi/6708.htm (this can't be done with bluetooth). Vems needs power all the time, so wired LCD and keyb power should be switched via FET/IGBT. Something else?
- Or could be used only for antitheft. If button no pressed car wont start or it could start but if MAP goes high car just stops, that would be nice. Or..
- Wireless LCD and some small keyboard or even PS2 keyb. Only problem is probably the batteries. How much does backlighted LCD draw? 5V * 20mA is reasonable, but backlight could be switched off. Recent PS2 use small (10..20mA) current. Feasible running on rechargable batteries.
Zigbee is great at small battery operated devices.
I have made a while ago proto HW with Nordic and old Atmel AT90S2313 uC. This chip does not have HW SPI so it's done by software and atmel-nordic works fine.
I think now that my goal is to make wireless zigbee link to replace the RS232 so all tuning softwares and terminal connection could be done thru it as now. But my personal goal after all is to make other wireless devices, I like to have central lock and also wireless LCD&keyb, not just replace wire to the laptop just like what bluetooth can do. Then these wireless devices needs to be used like comm commands. It needs vems code extensions, but it makes it really really flexible!
OR zigbee could be also connected I2C or SPI at vems, no need to touch comm commands if it's bad-bad. But then zigbee link cannot be used universal radio modem to replace RS232 connection. Give your opinion!
See also