Underwater Servo Kit SER-200X

• SER-2000: low-cost kit option that allows users to select and install their own standard-sized R/C servo inside our waterproof enclosure – including PWM, CAN, or serial servos – as well as their choice of either a Cobalt bulkhead connector or a cable with M10 penetrator.
• SER-2001: same as SER-2000 but with anodized aluminum lower case, rated to 400m.

Output shaft is a 6-mm titanium D-shaft. Titanium Servo Hub available separately.

See the Dowloads tab for the datasheet and assembly instructions.

SKUs: SER-2000 SER-2001

Blue Trail Engineering’s SER-2XXX underwater servos are compact, robust actuators for small marine robotic applications, rated to 200 meters depth with acetal upper and lower case or 400 meters depth with acetal upper case and anodized aluminum lower case. They consist of an off-the-shelf R/C servo installed in a machined enclosure with a titanium output shaft and waterproof connector. By using off-the-shelf R/C servos, this architecture leverages decades of servo development in the R/C industry to provide extremely high reliability as well as almost limitless options for speed, torque, travel distance, and other features.

The SER-2XXX series currently includes four models:

• The SER-2010 (200m) and SER-2011 (400m) feature the Hitec D954SW R/C servo. This is our least expensive model, producing 2.8 Nm of torque with a brushed motor.
• The SER-2020 (200m) and SER-2021 (400m) feature the Hitec HSR-M9382TH. This servo produces 3.3 Nm of torque and offers an extended travel range (up to ± 3.5 full turns of rotation with position control or continuous rotation with speed control). It uses a brushless motor and magnetic encoder, eliminating the most common causes of servo failure.
• The SER-2030 (200m) and SER-2031 (400m) feature the DB961WP servo, which produces 5.4 Nm of torque and uses a brushless motor.
• The SER-2130 (200m) and SER-2131 (400m) feature the MDB961WP-CAN servo, which produces 5.9 Nm of torque. It also uses a brushless motor and magnetic encoder, eliminating the most common causes of servo failure.

These servos are fully tested prior to shipping and have many programmable features, including travel range. If you require increased travel or any other changes to the servo's programmable parameters, we will happily program the servo per your specifications for free. Simply email sales@bluetrailengineering.com after placing your order. Alternatively, you may program the servos using the appropriate programmer.

We also offer the SER-2000 and SER-2001, kit options that allow users to select and install their own standard-sized R/C servo – including PWM, CAN, or serial servos – making this the most inexpensive and flexible option for underwater actuation. The kit comes with the output shaft, bearings, and seal installed, and the user completes assembly with the servo and connector of their choice. Servos must be of the “standard” size (20-mm width), they must have a 25-tooth spline, and they must have the proper height. The following servos have been tested for proper fit:

• Hitec D625MW, D645MW, D930SW, D940TW, D945TW, D950TW, D954SW, D955TW, DB961WP, MDB961WP-CAN, HSB-9360TH, HSB-9370TH, HSB-9380TH, HSB-9465SH, HSB-9475SH, HSB-9485SH, HSR-M9382TH
• GoBilda (all models)

If you would like to use a different servo, please contact Blue Trail Engineering and we will help you determine if your servo will fit.

Output shaft is a 6-mm titanium D-shaft. Titanium Servo Hub available separately.

You will need a regular Cobalt 3-pin cable (NOT a 3-pin Power cable) or Cobalt 4-pin cable (depending on the model) to connect to these servos.

WARNING: These servos do not have internal protection against overheating or overvoltage. They can be damaged or destroyed by:

• driving the servo against a hard stop for more than 5-10 seconds
• running the servo at high torque continuously
• applying more than the recommended voltage to the servo

Users should design their electrical and mechanical systems to avoid these scenarios.

FAQ

Q: What is the difference between the SER-20XX servos and the older SER-110X and SER-120X?

A: The main differences are:

• The enclosure walls are thicker, making the unit more durable and giving an increased depth rating of 200 meters.
• The surface finish is smoother and tolerances are tighter, making the O-ring seals more reliable.
• The external surfaces are flat for easier mounting from either the side or the top.
• It uses a 6-mm "D-shaft" output shaft instead of a square shaft, making it easier to attach to your device using a simple set screw.
• There is an available kit option, made possible by an easier assembly process.

Q: What are my connector options?

A: You can use either a bulkhead connector or a penetrator. The hole for the connector/penetrator is 10 mm in diameter. This gives the following options:

• Blue Trail Engineering Cobalt bulkhead connector - this is included with the pre-assembled SER-2010 and SER-2020. If you're assembing the SER-2000 kit, you can use this option as well. We recommend the 3-pin version.
• Blue Trail Engineering M10 Simple Penetrator - you can either buy a Cobalt cable with Simple Penetrator from us (this has a Cobalt cable connector on one end and a Simple Penetrator on the other end), or you can just buy the Simple Penetrator with some polyurethane tubing and make your own cable. We recommend using 1/4" tubing with the M10 size of Simple Penetrator
• Blue Robotics M10 WetLink Penetrator - this is probably the least expensive option. See the Blue Robotics website for more detail about the WetLink penetrators.

Q: What kind of fasteners are needed to mount the servo?

A: The holes in the top face of the housing are 16 mm deep and are intended to be used with #6 or M3.5 self-tapping screws like these. The screws should have between 12 and 16 mm of engagement in the plastic. The holes in the sides of the servo go all the way through the servo and are 3.2 mm in diameter, so use M3 screws longer than the width of the servo (which is 32 mm) to mount in this direction.

Q: How do I mount things to the output shaft?

A: The best method is to use our Titanium Servo Hub. Or you can use any type of 6-mm set-screw shaft coupling (including a homemade one), but be aware that the output shaft is titanium and you will get some amount of galvanic corrosion if you put a different type of metal in contact with it. You can also use a hub like these from ServoCity, but again, be sure that the materials are suitable for your application (putting aluminum in contact with titanium in seawater for an extended period of time is not a good idea).

SER-2XXX Datasheet

SER-2000 Assembly Instructions

Need CAD files? Please see the Resources page.