OK, you have to build a robot in 7 weeks and you just found out that Vantec is no longer taking any orders. What do you do? Well, here's some last minute advice.

Overview

Innovation FIRST makes a great 24 volt speed controller. A lot of people use the Victor 883 speed controllers because they are on a budget and they are only using 24 volts DC to power their robot. If all you need is to control 24 volts at no more than 80 amps, then I would reccomend the Victor 883.

This document will take you through the necessary steps to put together a basic, operating robot base using two Victor 883 speed controllers. It is not intended to prepare your robot's weapon.


Parts List

Innovation First Speed Controller (qty: 2, recommend 3, $150 ea.)


Victor 883 Model 24V 001 with a 24 volt cooling fan.
http://www.IFIRobotics.com
(903) 454-1978 Ask for Tony or Bob


JR PCM Radio and Matching Receiver Kit (1 kit, $400 ea.)


http://www.jrradios.com
Kit should include receiver and receiver battery
Note: you should be able to buy this at any local hobby store.


HLG Mixer (qty: 1, $30)


This little unit is not necessary, but you can use it to control both drive motors with one stick. http://www.tgworks.com/mixers.htm


Motor and Foamed Wheel Assembly (qty: 2, $275 ea.)


http://www.npcinc.com
You could save money by buying a regular tire and your own motor and hub (some info below), but if you bought this package you would know without testing that everything works ahead of time.
Call 1-800-444-3528, ask for Rich.


Servo Extension Cord (qty: 2, $5 ea.)


http://www.horizonhobby.com
Note: you should be able to buy this at any local hobby store.


12 Volt Batteries (qty: 2, $70 ea.)


Hawker G13EP or G16EP
Rose Electronics (408) 943-0200 Ask for Greg
Note: Any 13 or greater amp-hour 12 volt battery will work. I strongly
recommend using a battery that has terminal screw downs.


Sheet of 1/8 thick aluminum for building a battery box.

Online Metal Distributor


Automotive on/off switch (any toggle switch that can handle over 20 amps, screw down terminals prefered)


www.teamdelta.com


12 gage wire (red and black, 5 feet)


12 gage eye lugs (misc. sizes)


Duct Tape


Wheels (qty: 2, $30 ea.)


Northern Tool and Equipment part #1334-C121
1-800-533-5545


One Inch Bore Hubs (qty: 2, $13 ea.)


Northern Tool and Equipment part #138291-C121
1-800-533-5545


THE BUILD

Preparing the ON/OFF Master Switch
Cut two small (2 inch) pieces of 12 gage wire and strip the ends.
Crimp eye lugs to each end.
Attach one wire to one of the switch terminals.
Attach the other wire to the other switch terminal.
If needed, wrap some tape around the switch terminals to prevent shorting.


Preparing the 24 Volt Battery Pack from two 12 Volt Batteries


Arrange the batteries so that they make a square, positive and negative terminals pointing up, facing toward each other. Wrap duck-tape around the batteries.
Take your Master Switch (with the two dangling pieces of wire) and screw down one end to the positive terminal of battery A and the other end to the negative terminal of battery B.
Place a piece of duck tape over the battery terminals and lugs. Leave the other two battery terminals (your 24 volt) free for now. You should not have to worry about shorting the battery as long as the power switch is off.

Preparing the Radio Electronics Box
Find a cardboard box that can comfortably fit both the Victor 883 speed controllers, the radio receiver, and the radio battery. Tape the box to one side of the 24 volt battery pack.
You are better off putting the electronics in something more substantial, but if you're in a hurry, you're in a hurry.

Building the Battery Tray
The battery tray can be something as simple as a piece of rectangular plywood with some edging. However, if you want something a little more substantial, take your sheet of aluminum, cut out the corners, and fold up the four sides to make a box.

Place the 24 volt battery pack into the tray (along with the electronics box).
Wrap the batteries to the tray with duck tape. Note: feel free to use a better method of attaching the batteries to the tray. This is quick and dirty.

Preparing the Motors
If you bought the motor and wheel assemblies from National Power Chair you are in good shape. You'll notice that there are bolt holes across the top face of the motors. Get a 18 ince piece of flat, 1/4 inch by 4 inch aluminum. Drill four hole in both ends that match the hole pattern on the motors. You should be able to bolt the motors so that the wheels are perpendicular to the aluminum cross piece. You should be able to tape the battery box underneath the aluminum piece, between the two motors.
Also, be sure to remove the wheels from the motor shafts for testing.



If you did not buy the assemblies from National Power Chair you will have to attach the wheels and hubs you bought from Northern (see parts list above) to your own motor shaft. It might be tricky, and I cannot give you a whole lot of advice because I do not know what motors you might be using.

Preparing the Victor 883


The Victor 883 comes with a built in fan but the fan wires are not hooked up.
Strip the end of the small red and black wires and crimp on an eye lug. Bolt the black wire to where it is labeled "GND" and the red wire to where it is labeled "12V".
Do not worry about the "12V" label; it is a remnant of the tooling die. There should be a label on the front of the Victor 883 that clearly states "Innovation First Victor 883 Model 24V 001".


Attaching the Receiver to the Speed Controller
Take the female end of the extension cord and connect it to the Victor 883 where it is labeled
"WRB", which stands for white, red, and black. Do NOT try to connect the extension cord to where it is labeled "ABC". This ABC plug is not used.
Take the other end of the extension cord (the male end) and plug it into the PCM receiver where it says "Channel 2".
Repeat these steps for the other Victor 883, but plug the extension cord into "Channel 3".
Tip: you might want to label the tops of each Victor 883 "1" and "2".
If you bought the mixer (http://www.tgworks.com/mixers.htm) then you will attach the end of both extension cords (from Victor "1" and "2") to the mixer and then connect the mixer to the receiver.


Connecting the Motors to the Speed Controllers
This system has two motors. One motor runs the right wheel, and one motor runs the left wheel. Each motor has two wires, a red wire and a black wire.
All four wires should be stripped and have eye lugs attached.

The Right Motor
Take the motor wires (black and red) and attach them to Victor 883 #1 where it is labeled "M-" and "M+". It does not matter if you attach black to "M+" and red to "M-" or red to "M+" and black to "M-".
Run duck tape across the terminal and make sure there is no chance of shorting "M+" and "M-".

The Left Motor
Take the motor wires (black and red) and attach them to Victor 883 #2 where it is labeled "M-" and "M+". It does not matter if you attach black to "M+" and red to "M-" or red to "M+" and black to "M-".
Run duck tape across the terminal and make sure there is no chance of shorting "M+" and "M-".


Connecting the 24 Volt Battery Pack to the Speed Controllers
First, make sure the master switch is OFF.
Cut 2 long (8 inches) pieces of black 12 gage wire. Strip all the ends and crimp on eye lugs.
Cut 2 long (8 inches) pieces of red 12 gage wire. Strip all the ends and crimp on eye lugs. Bolt the two black wires to the negative terminal on the battery.
Bolt the two red wires to the positive terminal on the battery.
Run a piece of duct tape over the battery terminals to reduce the chance of shorting.
Take the other end of the black wires and connect one wire to the Victor 883 #1 where it is labeled "GND" and the other wire to the Victor 883 #2 where it is labeled "GND".
Take the other end of the red wires and connect one wire to the Victor 883 #1 where it is labeled "12V" and the other wire to the Victor 883 #2 where it is labeled "12V".
Again, do not worry about the label. This unit is made for 24 volts.
Run tape over the "GND" and "12V" terminals and otherwise make sure there is no chance for electrical shorts.

Position the Electronics
Place the 2 Victors, the receiver, and the receiver battery into your electronics box (that is attached to the battery pack). At the moment, the receiver battery should be completely free. Go ahead and plug the small receiver battery into the receiver. Once you have checked that there are no loose wires and everything is in its proper place, tape everything up and secure inside the box.


Bench Test
At this point the tires should not be attached to the either motor shaft.


Turn on your JR radio.
Turn on the main power switch.
One or both motors may slightly spin. It is merely creep and we will tune the system later. Right now we want to test the motor directions.

Check Number One
While standing behind the base, push the right stick forward. The right motor shaft should should run forward.

If you find that the left motor spins instead, turn off the master power. Go to the receiver in the electronics box and pull the two servo extension cords from channels 2 and 3. Switch their positions (channel 2 to 3 and channel 3 to 2). Turn the master power back on. Now the right motor shaft should spin when you push the right radio stick forward.
Push the left stick forward. The left motor shaft whould spin.

Check Number Two
At this point the tires should not be attached to the transmission shafts.
While standing behind the unit push the right stick on the JR radio. The right motor shaft should spin. Watch which direction the shafts turn. If the top of the shaft is turning away from you, then you can imagine that unit should roll away from you if it had wheels. Release the stick and then pull the right stick back. The right shaft should reverse direction and the top of the shaft should turn toward you. If the motor had a wheel it would be coming right at you.
If this is not the case then turn off the master power switch. There are two ways to deal with this problem. If you are familiar with the JR radio grip you can reverse the direction of channel 2 (the right stick). Or you can change the motor wiring for that right motor. I would recommend just switching the drive motor wires if you are new to all this.
Trace the wire back from the right drive motor to the Victor 883. Switch the wire from "M+" to "M-" and "M-" to "M+" for that Victor only. Leave the other Victor alone for now.
Turn on the main power switch. Now when you push the right stick forward the right wheel will spin the correct direction.


Check Number Three (last check)
At this point the tires should not be attached to the motor shafts.
Repeat Check #2 for the left motor.

Tweaking
The base should be responding the way you like. However, there is probably a little bit of shaft spinning that is occurring. The JR radio has a trim function for each stick. Play around with the trim until you can get the shafts to sit still without having to touch the sticks. Turn the master switch off. Pull the receiver battery plug out of the receiver. Turn off the JR radio.


Attaching the Wheels
For safety we did all these tests with the wheels off. Now that we have tweaked the system there is no reason why we can't attach the wheels.
Go ahead and bolt the wheels onto the hub. Take a quick look around and make sure everything is neat and tidy with no chance of a wire getting yanked out.
The battery box should sit about an inch or so off the ground, between the wheels.


Ready to Rock!
Since we already bench tested the unit, there should be no surprises. Turn on your JR radio. Plug the receiver battery into the receiver.
Take a deep breath.
Turn on the master power switch.

The base should respond to your controller.

Have fun!


If you have any questions you you can contact: christian@coolrobots.com