OPORCON ver 2
Please, check out OTIMCON https://github.com/stajp/otimcon - Arduino RFID based open source timing control. It has everything written below, and it's based on cheap components easily bought on eBay and similar websites.
OPORCON ver. 2 is under way. After looking at David's nice OPORCON
set and his improvements, and some ideas from others, I chose to start on OPORCON 2, to update my current system.
OPORCON2 will still be OPORCON1 compatible. By now, 3 slightly different OPORCON boards (my OPORCON 1, Bjarne's and David's) exist, but the data on chips is compatible in all systems. As I wish to extend my collection, OPORCON2 must (and will be OPORCON1) compatible.
Considerations on OPORCON2:
- it must have everything David's system has. Buzzer is a must, dip switch selection is a must. Warning system for course settler (when turning the system on) is a must.
- schematic must be simpler than David's system:
if possible, do some of the improvements which are left behind (eg. serial communication).
if possible, put in much smaller box than OPORCON 1 (this came after seeing David's system, and iButtonSport)
- There is no need for switches for whole PORTB (8 bits), if maximum number of controls is 127 (in fact, this is a lie, you can use DS1995 or DS1996, and extend maximum number of controls to 4000 or 16000, but I can't imagine a need for 4000 controls). I'll probably cut it to 32, it should be OK for 99% of trainings and small competitions on ARDF, orienteering, street and MTB-O.
- There is no need for additional hardware for buzzer when it can be done in software.
Ideas to contemplate:
- change iButton probe: Current probes on OPORCON1 are too big, so a big box was needed. I don't like David's keyfob probes, they look like too much work. Current ideas are:
use rechargable batteries:
- using standard coin cell battery holder. These are cheap online (already bought 10 pcs for 2US$), and they won't harm iButtons as much. In some test work they behaves excellent, but they look a little bit flimsy, it's hard to imagine them in the woods. Need testing.
- using a probe similar to iButtonSport system. iButtonSport is a system developed in Ukraine, which works remarkably similar to OPORCON, but for some reason they chose to use iButtons for controls in the woods, but carry boxes around. First probes had a screw for 1-wire transfer, newer have a flat piece of metal, but the grounding part of probe is done by using a single piece of wire, which wraps around. I tried the idea of using single wire on my adapter, but it didn't work as good as I wanted to that idea was scraped. Maybe it's time to come back to it.
- initial OPORCON used 9V batteries because they were the simplest way to make it work. I like the KISS (Keep it simple, stupid) idea, and I don't like David's step-up converter to get necessary voltage. His idea is that it will pay off after buying the next AA battery. On the other hand, last year I bough some 9V rechargable batteries for less then 4$ a piece. They aren't true 9V like alkalines, but more of 8.4 batteries. For OPORCON1 it's not even import if it's 10V, 9V or 8V, when there's a 7805 voltage regulator. So, for the price of 4-5 regular batteries + step up converter, I have a KISS 7805 + a NiMH rechargable battery. In the long run, I think this is a better option.
- Another idea is to use LiIon batteries. Online they cost even less then a PP3 NiMH battery, and give 3.7V. That voltage is (according to datasheets) enough for PIC, and for iButton, and for most buzzers. If 3.7V is enough, no voltage regulators are needed. After few charges it's cheaper than any other system. Must test OPORCON running on voltage regulated power supply, if it works this is a must.