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Affordable Lap Counters

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  • Affordable Lap Counters

    Three or four years ago I was able to find electronic digital counters on eBay for less than US$20 and tested them. They worked fine. I posted about it on SCI.

    The brand was DROK. I bought two of them to test. They came with magnetic proximity switches, which I found to be ineffective. But simply wiring the inputs directly to a dead strip worked fine. I did find that they had a preferred polarity. I also found it was helpful to connect a tiny capacitor across the inputs. (How tiny? Good question. So tiny it didn't have the farad value printed on it.)

    I tested those counters in parallel with my TrikTrax Mini-4. I just connected them to the same dead strips as the Mini-4. After 5,000 laps without a miscount I decided they were accurate.

    The downside: The DROK liquid crystal display was much smaller than the TrikTrax, and there was no lap timing function. The TrikTrax display is large enough that it can easily be read from across the room. You can't do that with the DROK display. And you'd need to buy some other unit if you wanted to time laps.

    That said, I've left one of those digital counters wired in parallel to one of the lanes on my TrikTrax. I can use the TrikTrax to display lap times while the DROK unit keeps the lap count.

    I should mention the DROK unit is powered by a single AA battery. It has no on/off switch. The LCD display draws so little power it can run continuously for years before the battery needs replacing. To date I have replaced that battery once.

    In the recent past I looked on eBay for the DROK counters and couldn't find them, which is in keeping with the ephemeral nature of brands from China. But there were others at similar pricing.

    But just today I searched eBay for "drok digital electronic counter" and found it again. The price has gone up. They now sell for US$23.09. BUT if you just search for "digital electronic counter" you can find a looks-identical unit selling for US$15.35, and a similar unit for US$6.72.

    My recommendation? If you are in the market for lap counters buy and test one of the DROK-style counters where they offer free returns. Wire it up with a tiny capacitor in series. Give it a try. See if you are happy with it. If not, send it back. If you like it, buy as many as you need while they're still available, and maybe even a spare or two.

    Or buy one of the US$6.72 units without free return and gamble that it will do the job for you. It might be the cheapest lap counter you'll ever find.

    Ed Bianchi

    NEWS FLASH! I've just found the DROK counter on Amazon for US$14.69. And if you just search for DROK on Amazon you'll find they sell a large variety of other electronic goodies.
    Ed Bianchi
    York Pennsylvania USA

  • #2
    I started a thread on a low cost lap counter for an HO track a few years back, possibly on SCI. I did not want to get involved with any type of computer or race management system. People had a hard time grasping that.
    Ed mentioned these counters. I gout four off eBay and started experimenting. I built a regulated power supply from a Youtube video.
    Actuation proved difficult. I tried various reed switches mounted in a variety of locations and positions before deciding on Radio Shack micro switches chopped into the track surface. Worked great.
    Only one time did I have issues with the switches. A drop of contact cleaner cured the issue.

    Next step will be trying this with a dead strip for actuation.

    Here’s my scoring tower. Each driver sees his lap count. Works great for timed races.
    Click image for larger version

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    • #3
      There has been much posting over the years about the best way to trigger a lap counter. The two systems that seem to work best are dead strips and light bridges.

      In my experience dead strips have the best record of simplicity and reliability. Dead strips have been used in slot racing since Day One. I have yet to see a commercial track with a light bridge.

      Other folks are just as adamant that a light bridge is the hot setup. And I am sure somebody will come up with examples of light bridges on commercial tracks.

      My motto is, "Whatever works." "Reliable as sunrise", is the goal.

      Ed Bianchi
      Ed Bianchi
      York Pennsylvania USA