This page contains project information and instructions for Johnny Astro accessories that you can build!  

• Power Supply - Build a power supply that will safely operate Johnny Astro, Vertibird, Chopper Command and Chopper Patrol.
  

• Landing Base Stand - A great addition to your Johnny Astro toy, this landing base stand has a space age look.  Flying to the moon and mars is even more fun!

Build this power supply and never buy batteries again!  Operate any toy that requires three or four D or C cells.  Emulating batteries isn't as simple as using an AC adapter rated for the equivalent voltage as the batteries it will replace.  In this article, We'll show you how to build a power supply that is the electrical equivalent of a new set of alkaline batteries.

COMING SOON! - Universal Adapter for Johnny Astro, All Vertibirds, Chopper Command and Chopper Patrol

Why not use a typical AC adapter?
Most AC Adapters are unregulated.  This means that the voltage swings dramatically depending on the load (current draw). For some toys like Johnny Astro, it could mean that the throttle would be difficult to control at low speeds and overheating at mid throttle.  For other toys, sensitive electronics could be overheated and possibly damaged.  Another problem is that many toys such as Vertibird and Chopper Command draw a lot of current, far more than a typical AC adapter can provide.   Most AC adapters are rated for 300mA to 800mA maximum.  Johnny Astro draws about 400mA while Vertibird and Chopper Command draw 2500mA! (2.5 amps)

The answer
When you factor in performance, affordability and size, RadioShacks' Digital Camera Power Adapter is tough to beat. This adapter is a compact switching power supply equipped with switch selectable voltage settings of 3, 5, 6 and 6.5 volts.  The output is fully regulated and rated at 2.5 amps.   With a retail price of US$20.00 it is a bargain and almost perfect for a toy power supply.

Connecting
Connecting the Power Adapter to a toy requires you to build something that will interconnect to your toy and the Power Adapter.  The Power Adapter comes with a few "Adaptaplugs" but none are suitable for interfacing to a toy.  We'll build an alligator clip and phone plug assembly that you can clip onto your toy, then connect to the Power Adapter.  The alligator clips safely connect onto the metal battery plates of most toys.  As a result, there is no soldering, drilling of holes, etc.  Build as many of these as you need, one for each toy.  

The need to add impedance
The Power Adapter will run Johnny Astro just fine without any modifications.  If however you want a universal power supply that will operate Johnny Astro and other classic toys like Vertibird and Chopper Command exactly as if they had new alkaline batteries in them, there is another step to take.  Our experiments have proven conclusively that the voltage on a fresh set of D cells in Chopper Command and Vertibird will drop significantly as the throttle is applied.  In fact, the voltage of the batteries starts at about 6.5 volts and drops to between 4 and 4.5 volts.  If you use the Power Adapter without adding some output impedance, both Vertibird and Chopper Command can  sustain damage at mid through full throttle.  Adding some impedance will ensure that the supply voltage drops off in the same way as alkaline batteries so as to limit the current being delivered to the toy.  To add impedance, we need to build an interconnect with a bit of resistance using a small piece of tungsten resistance wire.  The result is at little or no load, the voltage is regulated at whatever the switch setting is, 3, 6 or 6.5 volts.  However, when significant load is added, the voltage will drop exactly as alkaline batteries would.

If you don't want to build?
If you are not comfortable cutting wire and soldering, you can purchase everything except the RadioShack power supply from us.  Please see the Parts & Service page.  If you would like to tackle this project yourself, we can supply you with resistance wire for free!  Just provide us your address.

Build The Impedance Device

Parts;

• 1 - Digital Camera Power Adapter - #273-1695 (Radio Shack)

• 1 - Package of Two - Conductor 1/8" Inline Phone Jacks  - #274-333A (Radio Shack)

• 4 inches of 22 gauge speaker wire

• 2 inches of 1/8" heat shrinkable tubing

• 2 inches of tungsten resistance wire (2.58 ohms per foot)

• 2 brass tack nails that fit the Power Adapter pin holes OR Molex pins.

• 1 tie wrap (not shown)

Tools;

• Wire Cutters

• Wire Strippers

• Soldering Iron

• Heat Gun (or matches or lighter)

• Needle Nose Pliers or Small Pliers

The following instructions assume you are using a similar type of wire as shown on the right in Step 1.

Shown above is the RadioShack Digital Camera Power Adapter and the hardware needed to build the impedance device.

The Power Adapter end is not a common interface but small brass nails of the right diameter do the trick.

Step 1
Prepare the wire

1. Please review the line drawing below.
   
   
   
   

2. Prepare the wire so that the striped wire is 1 inch shorter than the solid black wire on one end and 1/2 inch longer on the other end as per  the picture.

3. Strip off about 1/4 inch of insulation from all four  wire ends.

The speaker wire is prepped for soldering.

Step 2
Solder onto the phone jack

1. Remove the plastic insulator from the phone jack.

2. Solder the striped wire to the phone plugs center lug and the solid black wire to the case lug.

3. Crimp the metal strain relief so that the wire is secure.

The wires are soldered to the phone jack.

Step 3
Solder the resistance wire onto the shortest conductor

1. Twist one end of the resistance wire to the shorter striped wire then solder it.  It is barely visible in the picture. 

The resistance wire is soldered to the shorter striped wire.

Step 4
Solder the brass nails

1. Wrap the open end of the resistance wire onto one of the brass nails so that there is about 1" of resistance wire between the nail and the wire.  It is important that the resistance wire is about 1 inch because this determines the impedance.

2. Solder the other wire to the second brass nail.

The brass nails are soldered on.

Step 5
Add heat shrinkable tubing

1. Slip on the phone jack's plastic collar and thread it onto the phone plug.  This end is now done.

2. Add heat shrinkable tubing to both wire ends so that the tubing covers all solder joints and the head of each nail.

Heat shrinkable tubing added.

Step 6
Shrink the tubing

1. Heat shrink the tubing.  You can use a lighter or a match in place of a heat gun. 

The tubing shrunk with a heat gun.

Step 7
Add the Collar & Align the pins

1. Disassemble the second phone jack and discard the metal piece.  You will be using the collar only.

2. Add the plastic phone jack collar with the threaded end facing the pins.

3. Snip the ends of the brass nails so that about 1/4 inch remains.  Now they are pins.

4. Align the pins by bending the one with the resistance wire in a "Z" pattern.  It helps if you heat up the tubing before you shape it.

5. Add a small tie wrap just before the pins.

A tricky part, the resistance wire lead is bent in a 'Z" so the pins align and a tie wrap is added.

Step 8
Insert the pins

1. Using needle nose pliers or something similar, push the pins into the Power Adapter pin holes.

2. Squeeze and manipulate the wires and heat shrinkable tubing to ensure the collar can move over the pins.

3. Later, you may have to swap the pins when we do a polarity check.

The pins are inserted into the power supply's pin socket.  Note that the phone jack collar is ready to thread onto the Power Adapter jack.

Step 9
Thread on the collar

1. Thread the collar onto the Power Adapter jack.  Even though the jack does not have threads, the plastic collar does and so it will thread its way on.  It is amazingly strong once complete.  The impedance device is now done.  The Power Adapter is now a completed power supply.

With the impedance adapter complete, the phone plug collar is threaded onto the Power Adapter jack.

Build The Alligator Clip & Phone Plug Assembly 

Parts;

• 18 inches to 24 inches of two conductor, 22 gauge speaker wire

• Alligator Clips (Test Clips) We used Mueller, 5 amp alligator steel clips, ten per package.

• 1 two conductor inline 1/8 inch phone jack, RadioShack # 274-333A

• 1 tie wrap 

Tools;

• Wire Cutters

• Wire Strippers

• Soldering Iron

The following instructions assume you are using a similar type of wire as shown on the right.

Shown are the alligator clips, 18" of 22 gauge speaker wire and a 1/8" phone plug.

Step 1
Connect the phone plug 

1. Strip about 1/4 inch of insulation off each wire.

2. Slip on the phone plug collar.

3. Solder the striped wire onto the phone plugs case lug and the solid black wire onto the center lug.  

4. Thread the collar onto the phone plug.  This end is complete.

5. Important! - If you plan to make make more than one alligator clip & phone plug assembly for other toys, ensure you wire them exactly the same way.  

The phone plug is soldered in place with its  collar ready to be threaded back on.

Step 2
Solder the alligator clips

1. Split the wires into two so that each lead is about 8 inches.

2. Cut one of the two remaining conductors about 3 inches shorter than the other.  This will reduce the chance of those leads shorting together.

3. Strip about 1/4 inch off each conductor and solder the alligator clips on.  

4. Crimp the flanges of the alligator clips over the insulation of the two conductors to act as a strain relief.

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The alligator clips are soldered onto the speaker wires.

Step 3
Hook-up and polarity check

1. With any toy, make sure the batteries are removed before plugging in the Power Adapter.  Failure to do so can lead to overheating of the batteries and possibly fire.

2. Plug the alligator clip and phone plug assembly into the Power Adapter, then plug the Power Adapter into a wall outlet.

3. The striped wire should be the positive lead.  If you have a volt meter, check the polarity.  If the polarity is revered, swap the pins where the impedance device connects to the Power Adapter. 

4. Once the polarity is correct, (with the Power Adapter  unplugged) clip the positive lead (striped) to the plate nearest to the throttle and the negative lead to the opposite side.

5. Switch the Power Adapter to 6.5 volts.  This is the voltage equal to four new D cells.  Next,  plug in the Power Adapter, then throttle up Johnny Astro.   If the polarity is correct, your Johnny Astro should operate as if you just installed new alkaline D cell batteries. If the thrust in minimal, reverse the alligator clips.  Reverse polarity will not harm Johnny Astro but it can do damage to other toys. 

The positive lead connects to a battery plate near the throttle.

The negative lead connects to the opposite side.

A landing base stand is the perfect addition to your Johnny Astro toy.  The stand elevates the Mars and Moon landing pads without the use of stacked books as the original instructions show.  We built two of them, both made out of black foam board and assembled using a hot glue gun.  Click on the pictures below for a larger view.