Mini SSC Hookups

Hooking up the Mini SSC is easy--so easy that it's popular with users who have limited experience in electronics. This page presents hints to make it even easier. Topics include:

• Connecting Multiple Mini SSCs
• Eliminating the 9V Battery
• The Real 'Maximum' Supply Voltage

This page is a work in progress. We'll add more hints and tips as time goes on.

Connecting Multiple Mini SSCs.

The Mini SSC is designed to allow multiple units to listen to instructions from one serial port. Each SSC responds only to instructions addressed to one of its servos.

In the simplest case, let's consider two Mini SSCs on one serial port. Both G pins get connected to host ground (GND) and both S pins to host serial output. ("Host" refers to the computer being used to command the SSCs.) Here's a diagram:

Multiple SSCs all connect to the same serial, ground inputs.

A solderless way to achieve this sort of hookup is by using Connectamundos™ jumper wires (CNX-010; $6/pkg of 10). These are flexible hookup wires with a female header socket at each end; the sockets slip right onto the 0.025-inch header posts. The photo below shows how these make quick work of connecting two SSCs.

Connectamundos™ make a neat, solderless connection.

Note in the photo that the second SSC has a jumper installed at I. This renumbers the servo outputs so that the output marked 0 is servo number 8; 1 is 9 ...and 7 is 15. With this arrangement, your program addresses servos 0 through 7 on the first SSC and 8 through 15 on the second SSC.

Making Your Own Connectors

You can readily make your own connectors for customized wiring harnesses. All it takes are a couple of hand tools, some hookup wire, and a little patience. An application note for our LCD products covers these techniques in some detail. It emphasizes the 5-pin connector used on the LCDs, but the same methods work for any 0.025" square header post.

Hobby suppliers' prices are mostly very reasonable, but servo-extension cables can be costly for what they are. Using the crimping techniques from the LCD-connector app note you can readily make your own.

Eliminating the 9V Battery

Most radio-control (R/C) circuits use separate power supplies for the servos and electronics. The reason is simple--to prevent heavily loaded servo motors from dragging down the power supply and causing the control electronics to malfunction. Servos can recover gracefully from a temporary brownout, but the electronics could reset, causing untold havoc.

Having a separate battery supply the electronics prevents this potential problem. However, in some situations it's inconvenient. Robotics company Medonis Engineering has developed a simple solution: the Battery Booster 12 supply eliminator.

The Battery Booster 12 is a switching power supply that can run the Mini SSC II off battery voltages as low as 2V. This allows the SSC to operate from the servo power supply and ride out all but the most severe servo-induced brownouts. The Battery Booster 12 is designed specifically to mount to the Mini SSC II--it even includes mounting hardware. See the photos below:

Battery Booster 12 is preassembled and includes mounting hardware.

This is a highly recommended accessory. Check out Medonis Engineering.

The Real 'Maximum' Supply Voltage

Some sharp-eyed users have pointed out an apparent contradiction in the current Mini SSC II user manual. Two different values are given as the 'maximum' power-supply voltage (through the 9V battery input):

• 10Vdc in the warnings
• 15Vdc in Mini SSC Power

Which is correct? Actually both are, depending on context. The Mini SSC II is protected against accidental reverse-polarity battery hookup. Users fumbling a 9V battery against the snap can't damage the unit. But the reverse-polarity protection won't handle more than 10Vdc (reversed). Above 10Vdc, reversed connection would damage the voltage regulator.

You can use supply voltages greater than 10Vdc (up to 15Vdc) into the SSC's 9V input, but you must make absolutely sure that you get the polarity correct.