Tam Valley Depot

Wiring diagram for the DRS1 receiver.  Wire colors correspond to wires on the harness.

The recommended battery is an 11.1V lithium polymer (lithium ion) 3-cell battery of 100 mAh or higher. In a test I found that a 120 mAh battery will run my sound-equipped Forney for 40 minutes with the wheels slipping. Obviously, the larger the battery the longer the time between charges. 7.2V, 2-cell batteries will work with most locomotives with some loss of pulling power.

An on-off circuit to disconnect the battery is needed. This can be a plug you pull apart or it can be switch.

If a lithium battery ledt connected after discharging it will be damaged. (Some batteries, like the SparkFun batteries reccomended below, come with a small circuit board to prevent this and to prevent over-charging.)

Be sure to read the instructions that come with lithium batteries - they are not as tolerant as other types of battery.

We recommend removing your battery and charging it in a coffee cup as they have been known to explode. If you cannot remove it, then charge it at the slowest rate possible on your charger.

DRS1 Mk4 Receiver, 916/869 MHz Auto-tunable
Receives the wireless DCC signal and creates DCC on-board from a battery to replicate the DCC signal to an existing DCC locomotive decoder. The Mk4 can auto-tune to either 916 or 869 MHz. Can also tune to any the 16 channls used by CVP making this receiver compatible with the T5000 handheld. The receiver works with all DCC decoders, including sound decoders, that use 2 Amps or less. The receiver basically replaces the red/black wires from the wheels. Comes with a wiring harness of 26 ga. flexible stranded wire.  There are 3 LED indicators: green indicates power, red indicates a DCC signal and blue indicates the radio strength. 

Receiver is 1.60" x 0.575"(1 5/16". The unit is 0.2" thick. Maximum continuous current is 1.5A continuous, 2A peak.

Battery not included. 11.1V (3 cells) and 14.8V (cells) Lithium ion batteries work well (do not exceed 18V). Or use 3 portable phone NIMH batteries (9 cells) for 10.8V).  One advantage of the NIMH option is you can arrange to trickle charge them from the track.  On my personal layout I use trailing battery cars with 1000 mAh Lipo batteries for several hours of runtime.

Use with DRS1 Transmitter (see below) or a T5000.  Fullly compaticble with older DRS1 916 or 869 MHz transmitters.

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The DRS1 receiver works with all brands of DCC decoders.  Decoders can be programmed through the radio by connecting the transmitter to the service track (no read back), using programing on the main or use the T5000.

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Note: When removing the wiring harness be sure to pull gently on the plastic connector case with a pair of nippers or sharp tweezers - do not pull the wires or they will come off! Maximum voltage for the battery input is 18V DC - do not exceed! Connecting the battery backward will not do any harm but the unit will not work.

DRS1 Mk4 HiPower Receiver, 916/869 MHz Auto-tunable
Same as the DRX040 except can put out 5 Amps. Suitable for O and G scales. Receives the wireless DCC signal and creates DCC on-board from a battery to replicate the DCC signal to an existing DCC locomotive decoder. The Mk4 can auto-tune to either 916 or 869 MHz. Can also tune to any the 16 channls used by CVP making this receiver compatible with the T5000 handheld. The receiver works with all DCC decoders, including sound decoders, that use up to 5 Amps. The receiver basically replaces the red/black wires from the wheels. There are 3 LED indicators: green indicates power, red indicates a DCC signal and blue indicates the radio strength. 

Receiver is 2.80" long x 1.20" wide by 0.5" thick. Maximum continuous current is 3.5A continuous, 5.4A peak.

Battery not included. 14.8V (4 cells) Lithium ion batteries work well (do not exceed 24V).

Use with DRS1 Transmitter (see below) or a T5000.  Fullly compatible with older DRS1 916 or 869 MHz transmitters.

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The DRS1 receiver works with all brands of DCC decoders.  Decoders can be programmed through the radio by connecting the transmitter to the service track (no read back), using programing on the main or use the T5000.

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Note: When removing the wiring harness be sure to pull gently on the plastic connector case with a pair of nippers or sharp tweezers - do not pull the wires or they will come off! Maximum voltage for the battery input is 18V DC - do not exceed! Connecting the battery backward will not do any harm but the unit will not work.

DRS1 Transmitter, 916.49 MHz, MkIII
Takes the DCC signal from your existing command station and puts it on the air to be picked up by the receiver(s) in your locomotive(s) (see above). Simply connect to the back of your command station to the rail outputs and place in the center of the room near the ceiling.  Use twisted pair or speaker cable for long runs (> 10 ft) back to the command station. Since the transmitter only draws 21 mA, the wire can be as small as 28 ga. Only one transmitter is needed for the entire layout. This device transmits low power radio frequencies on the Instrument-Scientific-Medical (ISM) band (also used by 900 MHz cordless phones) with a range of about 50 feet.

Dimensions are 79mm (3.125") 20mm (0.812") long by 15mm (0.635") thick. Input: DCC 5-30V peak-peak; uses 28 mA (.03A). Ouptut -4.3 dBm 916.49 MHz.

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DRS1 Transmitter, 869 MHz ("euro"), MkIII
This is the same transmitter as the 916 MHz version except that it operates on the 868 MHz "euro" ISM band and pairs with the 869 MHz receiver.  Will not work or interfere with the 916 MHz receiver.

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Gold-plated Breakaway Connectors - I use these to make connections between the battery and the receiver.  They are small, easy to plug and unplug and electrically reliable. Receptacle - Digi-Key SAM1115-32-ND. Header - Digi-Key SAM1111-32-ND.

Litium Polymer batteries - A good source is Dead Rail Installs (see above in Links). All RC stores that carry small electric airplanes and helicopters will have small 3-cell batteries. They can usually be made smaller by cutting off the heavy casing and adding a smaller connector made from breakaway headers (above).  these batteries usually do not have circuit boards built in to them to protect them from over-charging and over-discharging. You can also get single small LiPo batteries from Pololu, Sparkfun and Adafruit that you can make in to packs.

Portable phone batteries.  These are usually 3-cell NIMH bateries and are available nearly everywhere including drug stores for a good price.  Connect 3 packs in series for 10.8V.  Can be trickled charged from DCC by suing a diode ans a 20-Ohm 0.5Watt resistor.  Details are in the DRS Book.

Battery Charger. I like the HiTec X1. It can charge just about anything. It is not easy to use but then none of the better battery chargers are - they are just too complicated. I got mine by searching amazon but most RC stores have them and the helpful person behind the counter may be able to show you how to set it up to charge the battery you just bought.

Electronic Switch - You need a switch rated at least 1.5 Amps to turn the battery on and off. These can be quite big and bulky. I often use a shunt (jumper) across the pins of a breakout header.  An alternative is to use an electronic switch.  This has a small momentary tactile switch that is used to toggle the power - Pololu Pushbutton Power Switch. I have mounted the pushbutton so that it can be toggled by a bamboo skewer through a small hole or window. The board has a green LED so you can tell when the power is on for locomotives without sound.

Reed Switch - An even better power switch can be made by replacing the pushbutton on the Pololu Power Switch with a small reed switch.  You can then turn the power on and off with a small magnet. The reed switch can be hidden inside the shell.  A small reed switch is available from Digi-Key 374-1083-ND. Small super magnets are available at hardware stores. I taped one to a small screwdriver to make my "magic wand" for turning my locomotives on and off.

Flexible Wire - TCS sells small very flexible 30 ga. wire in multiple colors. Also useful is solderable magnet wire from All Spectrum Electronics.

Frequently asked DRS1 questions:
Q: Can I consist DRS1 equipped units with my conventional DCC locomotives?
A: Absolutely. The DRS1 locomotive receives and obeys DCC commands as if it wre still connected to the track

Q: Can I program decoders in DRS1 equipped locomotives through the transmitter / receiver connection?
A: Yes, with Programming on the Main (Ops mode) you can program your locomotive. However, some decoders (e.g.Tsunami) will not allow changing the loco address in Ops mode. In this case you can attach the the decoder directly to  the pragramming track. The DRS1 has a plug that can be removed and connected to an adapter to make this easier.

Q: Can the receiver send commands and power to more than one decoder? I have several locomotives with separate sound and motor decoders
A: Yes. You can attach as many decoders as the current limit will allow.

Q: What about automated control from cab bus equipped modules like NCE mini-panels, loconet, xpress-net, NMRANet etc.
A: These are all cab-bus or accessory bus devices. The DRS1 does not change the way the cab-bus behaves in any way - it is connected on the track side of the command station.

Q: Can I still run these equipped locomotives at my club or friends layout?
A: No problem. Simply bring along your DRS1 transmitter and attach it to the track with some alligator clips in an out of the way location. You can now use your freinds throttles to run your wireless DCC locomotive (be sure to run it on the floor just to show off!).

Q: How many receivers will one transmitter accommodate reliably.
A: There is no limit. The receivers do not draw any power from the transmitter.

Q: Is there a way to prevent locomotives from continuing to run all the way to the floor if they do leave the track,
A: Yes, grab them. This is a portential new danger for on-board battery power (and keep-alive circuits).