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Posted on 19/09/06 12:48:04
mike
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PC based lap timing & power control
Hi All,

I started this topic as a way of asking everyone their opinions of the various ways of setting up pc based race control.

Questions I would put to you all are:

1/ What software & why? UR30?, LT2k?, one of the non free ones?

2/ Do you use the power control facility in the software or just the lap timing?

3/ Type of sensors? Reeds? Hall Effect? Microswitches? LDRs? IR?



Posted on 19/09/06 12:55:15
Chadly

Posts: 476

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Re: PC based lap timing & power control
ummmmmmmmmmm, don't ask me.
This is a question for ppl of more HO exp than me.


Posted on 19/09/06 13:43:58
Dave in Perth

Posts: 873

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Re: PC based lap timing & power control
LT2000, track relay installed (works perfectly unless Geoff comes over )

Reed Switches, have used them for years and never had any problems.

I do have UR30, it works reasonably well, made a PC controlled start light bridge for it too. But LT2000 is simpler, easier to use.

Posted on 19/09/06 14:48:25
richard

Posts: 200

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Re: PC based lap timing & power control
I'm also looking at using LapTimer with Reed Switches. But I have to build my track first!!

_________________


Posted on 19/09/06 15:20:16
mike
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Re: PC based lap timing & power control
Dave in Perth wrote:
LT2000, track relay installed (works perfectly unless Geoff comes over )

Reed Switches, have used them for years and never had any problems.

I do have UR30, it works reasonably well, made a PC controlled start light bridge for it too. But LT2000 is simpler, easier to use.


I agree with you on ease of use. Also UR30 seems pretty buggy to me, often plays up.
One thing I don't like about LT2k though is that after a race, if you go back into the setup window it re-connects track power. This can be quite frustrating when you've got a bunch of youngsters raring to go & your race control is all mucked up after the first or second bracket because someone has started driving again.

Something else that's less than ideal with both of them is that if you want pc power control you have to use the printer port. Therefore, if you want to be able to print out race results you have to fit a second LPT port.

Posted on 22/09/06 16:06:49
mike
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Re: PC based lap timing & power control
Richard wrote:
I'm also looking at using LapTimer with Reed Switches. But I have to build my track first!!


Richard, I have a strong preference away from reed switches based on past experience in other devices. I can understand a reluctance to go IR with physically seperate LEDs & IR receivers but it is an electronically simple build. I've got them working pretty well though & I would back them for accurracy against any reed arrangement. Geoff tells me that to get the reliability he had to place them near a corner & personally I see that as too big a disadvantage. Now that I have the IR setup working I'm going to see whether I can get the hall effect devices working. The units I've gotten hold of are extremely sensitive & very fast reacting, (unlike reeds) but their biggest problem is they have a very small output voltage differential which means they need to be coupled with some kind of op amp arrangement. I intend to see if I can get them to trigger a 555 chip in order to acheive the TTL level output that the PC requires. It shouldn't be too tricky & if successfull it would out perform anything else I've heard of.

All I'm saying is keep your options open untill you have to decide.

Posted on 22/09/06 20:00:26
soccerkiddo3

Posts: 207

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Re: PC based lap timing & power control
Mike

Pity Cam is away. I can almost hear him agreeing with you from the other side of the world about reed switches and their use but my experience is that they are oh so simple and extremely effective. The only limitation is to place them at the start of a straight rather than the middle or end of one.

For guys like me that wouldn't know a 555 chip from salt and vinegar, reed switches are the way to go.

Geoff


Posted on 22/09/06 22:35:48
Dave in Perth

Posts: 873

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Re: PC based lap timing & power control
my reeds are fairly close to the start of the main straight, but the cars arecoming out of some fast corners so I don't think it matters..

Install the reeds with the slot (gap) vertical, much more consistent operation. And use shielded cable.

Posted on 23/09/06 07:57:16
mike
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Re: PC based lap timing & power control
Hi Geoff & Dave,
Fair enough. Clearly, so long as what you use works then little else matters. I'm curious though, don't you ever find anomalies in the timing sheets after an event that would indicate a reed has failed to trigger? The software provides de-bounce so I'd be surprised if they double or triple register.
Just one last comment before I pull my head in on the matter. As a general Engineering principle, the more moving parts in a system the lower the reliability of that system. On that score semiconductors, (in some form) are the way to go I recon.

Posted on 23/09/06 15:42:44
mike
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Re: PC based lap timing & power control
Ok, I'll attempt to upload the schematic & parts list for the Track Power Module, (TPM) here as requested by Richard. If it doesen't work or is hard to read emal me at somitec@mail.com & I'll send it as a pdf.

App Notes are:
1/ SW1 is included to disconnect the pc from active control while manual control is still available via SW2. I had to include SW1 because of LT2k's annoying habit of re-connecting power to track at inconvenient times. Neither switch is essential but SW1 is recommended.
2/ Pretty much any LEDs can be used but I wanted HI units so they are visible in high light environments. Be advised though that these units have a viewing angle of 15 degrees & so a diffuser may be necesarry depending on where they're placed.
3/ Circuit Breakers can be used in place of the fuses but I recommend the manual reset variety.
4/ There are many NPN transistors that can slot in in place of the BC547. I had a couple kicking round so that's what I used. Some others would be BC107, BC207 & BC147.
5/ I've specified Jaycar - sourced bits here because I've seen you guys mention them before but I doubt there's anything in this that can't be sourced from Altronics, DSE or even Oatley for that matter.

[Attachment: TPM.pdf (63.58kb)]




Posted on 23/09/06 16:32:49
Dave in Perth

Posts: 873

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Re: PC based lap timing & power control
yeah debounce is easily set. Also gotta bring your timer resoltion down to 1 ms otherwise the PC misses it sometimes!



Posted on 25/09/06 10:09:46
Karl

Posts: 261

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Re: PC based lap timing & power control
Hi Mike.
I agree. as long as it works, it doesn't matter what you use. I am ok at electronics but still use the reeds as I have not had any problems therefore using the KISS method (while it lasts)

My reeds are 24 inches from the exit of a slow corner at the moment but at one stage were near the centre of a 3 meter straight with no probs.

Geoff, you may have a dodgy reed. Unlike Dave's, mine are placed with the air gap parallel with the track face and I don't use shielded wire.

Mike - if you do get a schematic drawn up for your lap counting setup (Hall Effect) I would love to see it.

Cheers
Karl

Posted on 09/10/06 14:10:56
mike
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Re: PC based lap timing & power control
For those interested, I've been in touch with Greg Braun, re. LT2k's habit of reconnecting track power at innoportune times. Greg's response was.

"I'll see what I can do in a future release, but for now
you can use the Race | Track Power (F10 shortcut) menu
command to toggle track power on and off.
The Lap Timer 2000 main window must have the focus when
you use the F10 key."

I still find the use of an isolation switch more usefull but I'm looking forward to the next release of LT2k.
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