A wall wart would do.ĭepending on how many total sensors one would want in their track layout this could become quite an expensive route to take. Those that don't could pull power directly off the track with a bridge rectifier and a 5VDC regulator although that's getting away from off the shelf. Many model railroaders have comparable power busses under their layouts. I'll have a power buss available with +-12VDC and +5VDC. Well that does fit the off the shelf criteria but then each sensor node costs what a ID sensor and XBee unit costs, plus you still have to figured out how to power them. Just look at what Bluetooth costs for an Arduino! You're right about costs at the hobbyist level.

They're just too close for the reader to handle. Many tags are missed when they are placed at the mating ends of cars. Tags start to be missed at higher speeds. Testing has shown that if tags are centered betweens ends of the railcars then a train can pass over the reader at up to 50% of max scale speed with 100% read accuracy. With the CoreID reader it will report only one tag when more are within range. Also look at the specification of that sort of reader as readers that only output their code once often have a delay before they can read another tag.

If you have a tag on each carriage you must make sure the tag from one leaves the reader's field before the next one enters. Aren't TTL and RS232 levels two different things? All I'm familiar with are serial port multiplexers - like those used years ago to mux many serial terminals over one telco circuit. There are very few types of multiplexer other than TTL ones.

Even though model railroading requires some soldering skills, it seems that few modelers have any interest in electronics assembly. The CoreID's output is serial but it's TTL so is there such a beast as a multiplexer for that? Please keep in mind the goal is to use off-the-shelf hardware. There's one chance to get the read and then it's gone. The CoreID readers we've tested do NOT repeat a tag's info unless the tag goes out of range and returns. The data rate from each reader probably wouldn't be more than 1 tag per second as a train passes (1 tag on each car). The CTC computer for a model railroad is often in a different room and because of the twists and turns of a layout it could easily be 200' away as the cable runs.

Since it's a hobby, we're trying to keep costs down. A group of us are trying to pick off-the-shelf hardware that can be ordered and hooked up by most any modeler without the need for much (if any) soldering or use of discrete components. Actually, this is for model railroad use.

Serial port multiplexer arduino