Introduction: Building the ServoBoss, a Servo Tester From

This is the ServoBoss. It is a servo tester capable of driving up to twelve servos simultaneously.
The kit is available from

It currently has eight programs.

Program 1 - Set milliseconds
Adjusts output to twelve servos (two groups of six) in .001 millisecond increments using pushbuttons. Displays pulse-widthsetting on LCD for both groups. The second group is reversed in all programs except for Dead Band.

Program 2 - Adj milliseconds
Using a pot, controls twelve servos while displaying pulse-width on LCD.

Program 3 - Dead Band
Alternately sends two pulses differing by X microseconds. X is adjustable from zero to 99 and is displayed on LCD. Increase the setting until servo jitters, then back down by 1 uS increments to find the Dead Band.

Program 4 - Cycle Servos
Enter High End, then Low End, then number of cycles, transit time and finally, the pause time. If number of cycles is 0 it will run indefinitely. Transit time is adjustable from 20 milliseconds up to 60 seconds. Pause time is adjustable from 0 to 60 seconds - anything under 10 milliseconds is ignored.

Program 5 - Sweep Servos
This program is nearly identical to Cycle Servos except that a button press is required for each stroke.

Program 6 - Set Three
In this program you set three pulse-widths. One each for Low, Center and High. Press one of the three buttons and it sends the servo(s) to the corresponding setting.

Program 7 - RX Input
Connect your RC receiver or other servo signal producing device and read up to six channels. Displays pulse width in 1 uS resolution. The incoming signal is passed on so that you can control your servos while reading the pulse widths.

Program 8 - Battery Pack Test
Displays voltage of battery pack, .01 v resolution, a few hundreths of a volt accuracy. This program always runs at start up. Good for checking for charged packs - just plug it in - no button presses required.

Step 1: Organize Your Work Space!

Clear a well lit space to assemble the kit and get your tools together.

Step 2: Inventory the Parts.

Make sure all the parts are there. If not, make sure to let the folks at GadgetGangster know right away.

Mouse over the second image to get a description of all the parts.

Step 3: Get Familiar With the Circuit.

Take some time to explore the circuit. Mouse over the images to get a description of the components.

To get a real close look, click the i in the upper left corner of the image and choose "original".

You will need to decide how you are going to power the board and servos.'

Option 1: Use the battery connector at the far right to power both the board and the servos. This is the preferred method.

Option 2 : Use a wall wart (up to 12 volts) plugged into the 2.1mm barrel jack to power the board. The 5 volt - 3 amp regulator then powers the servos. This would be OK for light duty but you can overload the regulator if you drive the servos too hard or drive too many servos.

Option 3: Use a wall wart (up to 12 volts) plugged into the 2.1mm barrel jack to power the board and a separate battery pack to power the servos. Very important - do not install the jumper that goes from the diode location to row T!'

Step 4: Now to Start Soldering.

If you took the time to familiarize yourself with the circuit you should be able to put it together with no further information.

Start by soldering all the jumpers and resistors on the front side of the board.

Generally, you want to start with the lowest (height wise) components first so that when you turn the board over to solder they don't fall out. Sometimes though you have to put things in that just won't stay. A simple solution is to use a piece of masking tape to hold things in place. The blue tape works best.

There is a small jumper going from 17, D to 17, E. Install it early on because there are two things above it.

Step 5: Calibrating

Calibrating is now an optional step. The ability is retained just in case it is needed but the default settings should work out pretty well. Until there is a need to enter the calibration menu I would recommend against it and I won't bother to show how it's done. Of course, if anyone needs it, just let me know.