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SPAI is not written in the wrong way !
SPAI stands for:

Short Period Astetics Intelligence

In fact you can build these little fellows with as less as 6 components, including the power source and the two motors ! YEP, very small and easy to build. They give you great fun, believe me !

These bots are powered by a Gold Cap and for a period of about one minute they move, always looking for the brightest lightspot, so in fact they will even follow a lightsource.

It is always a surprice that with so few components you can do so much.

All these bots are powered by a 3,3F Gold Cap ( F= farad). You can charge them with a regulated power supply. I use mine at about 3,8 Volt. Don't use more ! Within a few seconds the Cap is loaded and in the beginning a current of more then 2 Amps can flow !

The first picture shows SPAI BIG . This one uses a CD74HCT240 as brain. With the two 5 mm red LED's it is capable of following a light source. The legs are bend from a paper clip and the motors are "pager" motors.

The second bot (picture 2 and 3) is almost the same as SPAI BIG, it is just a little smaller. I gave it a nickname : Longface ( just look at the pictures, and you'll understand why...)

Instead of a 240 it's brain is formed by a 74HC14, I've these IC a lot !

Did you see how small this bot is ?

In the last picture you can see my micro Herbie. A LM386 is used as brain. In fact this one isn't working as it should, but I wanted to show it in a picture.








This is micro Herbie !



What does this mean ?

Well, Ali stands for

Act Like Intelligent

They are small bots with just a few components. At the moment I've build two of them. They look the same but have a different power source.

ALI 4,8V is working on 4 small batteries (110 mAh) and ALI 9V is powered by a rechargeble 9 Volt battery.

When ALI bumps into something it will go backward for a short time and then go forward in another direction, so they will find their way all alone.

Just believe me, you have to see them working, the 9Volt one is very very quick !

The basic circuit I've found on the homepage of Solarbotics (look into my links), With a few adaptions I could make these small bots.

These pictures are from ALI 4,8V.

The 4 pins connectors is used as a switch.

For circuit and printed circuit look at ALI 9V






This is ALI 9V

As written earlier this is the same bot as ALI 4,8V but now it is powered with a 9Volt battery.

Look at the picture of the backside. There you see a piece of metal bended to give a smooth third support.

The two resistors and the two capasitors can be changed quickly so it is possible to change it's reaction.

If you look close to the picture of the side , you'll see that I've written a big + on the 9 volt battery. In fact after installing the battery the bot didn't work. After searching for mistakes and testing with a external power supply the bot was oké. The battery was also oké, but hey, wait........

They had make a mistake on the battery ! The + and - were named in the wrong way ! Maybe because of this mistake they were very cheap !

So beware........


Click on this small circuit to get the "big one" !

Don't forget to place the "red" jumper.


Pathfinder 1


This is a small bot that can play some kind of "soccer".

Easy to build with just a handfull of components.


For more picture of these bots and how the electronics work, click here.


This is a small bot with its own lifecycle.

MINIBUG and MICROBUG are build with the same principle of working.

For more picture of these bots and how the electronics work, click here.


This is a really small bot. It only consists of two components ! I've used a 1F capacitor and a pagermotor. To make it look nice I"ve also attached wings, made from a piece thin plastic.

There is not much to tell, just do some experimenting on the legs. The legs are the wires from the 1F capacitor. Just solder the two motorwires to it and glue the motor on to the capacitor. I've put some silicon tube to its feet, looks nice.

Charging is done by holding a 1,2 V battery to the legs for about 5 seconds. Just watch the polarity!!

The 9V battery on the picture is only to give an idea about it's size.

When charged up, it vibrates, moves and turns for almost 20 seconds, always swinging it's wings. It even makes a buzzing sound!


SPIDER.jpg (456716 bytes)


This is a small and easy to make bot. With some soldering experience it can be made within two hours.

Besides that it is also very quick, that's why I named it Quickly. Thanks to the special construction it can be made in two versions, only by making other connections to the both motors. The first one is a light seeker and the second one is a line follower. This version I like very much.

When you are making the line follower you need to place the small light bulb. The light seeker doesn't need it. You also have to bend the SHF205 infrared diodes a little!

The only part that can give you some difficulties is the soldering of the battery connectors to the circuit. I've made two small holes (1/10 inch or 2,5 mm) in the circuit, and then put in a small, just fitting screw. This will give extra strength to the joint, especially when you want to remove the battery often. Don't use too much solder on the joints, especially when you are mounting the - connection, otherwise your battery won't fit at all.

The motor frame I've made out of a piece of brass, 1,5 mm (1/15 inch). Bend it in the way as shown in the drawing. The same material is used to make the support system. Make sure the battery (when placed) doesn't contact the small ball (bead).

When you've finished mounting the electronic components, don't forget the wire connection, then solder the frame to the circuit. The motors are attached (soldered) at last. Use a good soldering iron, then this will give you no problems.

With the variable resistor (100k) you have to adjust it's behavior. I had to turn it almost to one side. Take good care doing this, otherwise your bot will only make turns. Adjusting will take several attempts!

Power consumption is less then 120 mA, so a good charged 9-Volt block (NimH) should give power for about one hour.

For the printed circuit I've used a piece of Uni. board: 13 by 11 holes.

Total costs can be as low as Fl 10, -- or 4 US dollars, that's without the battery.

When everything is ready and checked twice, put in the 9 V block and watch what it is doing. I'm sure when you haven't made any mistakes it will work fine, and give you, or your children a lot off fun.

For the line follower version you have to bend the SHF205 somewhat, so they are facing away from the light bulb. For more details look at the pictures.

For this version you can draw a line on white paper, or mark a line with some black tape. It should be about 5 to 10 mm (1/6 - 1/3 inch) wide. The loops in the line (turnings) shouldn't be to small: 10 cm (4 inch) will do fine, otherwise the bot can't follow it, and will get lost!

By the way, the line follower will act as "afraid off light" when it can't find a line! When the surrounding light is to bright, you may have to cover the topside of the SHF205's with some black tape.

If the grip of your motor axes is to less, then put on a small piece of silicon tube. Have fun with this little robot.

For more details, look at the pictures. There are pictures as a line follower (lightbulb) and pictures as a light follower.

Quickly circuit

Quickly printed circuit

Herbie reverser

This bot is made with almost the same electronics as Quickly.

It uses other motors (servo geared motors) and is a lightseeker.

The wheels are made from aluminium.

When bumbing into something it can also reverse for several seconds. The time of going reverse can be changed. I've used 2M2 and 3,3 uF, this will give a reverse time of about 5 seconds. Using a bigger C (6,8uF) or a bigger R (3M3) will give a longer reverse time.

For the bumberswitches I've used two micro switches. They are connected parallel.

For power I've used 6 rechargeable batteries ( 250 mAh). To give it more speed you can also use a 9 V battery. Just as in Quickly there is a third support on the back. You can see it in the pictures.

The construction is very easy. To pieces off 8mm (1/3 inch) thick plexiglass are used to connect both servos. They are also used to mount all the other components, as can be seen in the pictures. Use the big, round servo arms and glue the wheels directly to it. Make sure they are good alligned.

As I said before it isn't that difficult to make this small robot. Just give it a try !





Herbie circuit

Herbie printed circuit


On one off the Internet homepages I found a picture of a spider bot.
You can see the result off the bot I made on the picture.
It works fine, but the legs (made off guitar strings) are a little to stiff.
The bot wonít move, it just vibrates and makes ticking noises.

Circuit = solar engine.

R= 10K , C= 4700 uF, two red LED (eyes).


SPIDER.jpg (456716 bytes)

Spider circuit

Spider printed circuit

Solar speeder.

With this one I tried to make a solar speeder just under a solarcell 24X33 mm.
It took a lot of time experimenting to get it run.
Ok, finally it worked but needs a lot off light to trigger and "run off".
The energy is stored in a Gold cap off 0,033 F (= 33000 uF).


SOLAR SPEEDER.jpg (444428 bytes)

Solar fly.

This bot is free formed and uses two coils from VU meters (stereo) to move its wings.
Make sure you get a left and a right one !

As you can see, the head and tail are made of electronic components.

By the way it doesnít need much light to move the wings several times per second ! Sometimes I eaven have to cover a part of the solarcell.

With this simple design it's very important to allign the wings. Slightly difference in balans and the wings won't move in the same way, looks like the fly is drunk !

The wings are made out of thin plastic.


R= 1Mohm variable resistor ,C = 100 uF , red FLED

250 Kohm will work even better !







solar fly circuit

Head of a fly


This bot is totally free formed and uses only one coil from a old VU meter to move its wings.
Solar power comes from a solarcell of a old calculator.
As you can see, the head and tail are made of electronic components.
By the way it doesnít need much light to move the wings every few seconds.

R= 68K , C= 2*100 uF + 47 uF + 33 uF + 22 uF, red FLED


LIBELLE.jpg (435212 bytes)

Libelle circuit


LIBELLE ACHTER.jpg (398348 bytes)

Head of a libelle


Light head.

This "head" is based on a circuit I found on one of the exciting homepages.
It works great, and always turns the head to the brightest lightspot it can find.
The electronics consist only of three components and the oscillation is slightly depending on the brightness of the light.
Look at the polarity of the two LEDís, they are used "up side down".
Be sure you use a motor (with gear) and a low mA demand.

2 stacked 74HCT240, 2 red LED ( not FLED!)


LIGHT HEAD.jpg (389132 bytes)

Lighthead circuit


Bully is a reversing photovore or light seeker.
For the LEDís you can almost use any type or color, I used red ones 5 mm.
For "power" I gave it a 3,6V / 60 mA accu and used two small, geared motors.
By stacking two 74HCT240ís you can drive the small motors directly without a "transistor bridge".
This works really fine so far without any problems!

When you "power on" Bully it will first go backwards for some time. After a few seconds it seems that it doesnít know what to do, it looks like itís shivering. Then it starts of going to the brightest lightspot it can see, first slowly and then like "in a hurry".
When it reaches the lightspot it makes turns which make it look like itís happy!
In the time doing all this stuff, each bump into a obstacle makes it move backwards for a few seconds. The time doing this can be changed with the 10 uF elco. Smaller means less seconds and bigger means reversing for more seconds.

Only with these few components you can get this great behavior and reflexes on itís environment. Astonishing, isnít it!
I think that it would also look great to make a small, solar powered photovore, using this circuit: a photovore that can backup.
Maybe my next "insect like" will be made in this way, who knows?
The result will be shown on this homepage.


BULLY+MUNT.jpg (388108 bytes)

Bully circuit

Bully printed circuit


This is the low-budget Marslander NASA is currently working on. It doesn't do much (just like the expensive Marslanders), only the radar turns slowly.

R= 25K variable resistor, C= 2*47uF, red FLED

Marslander circuit


This is my second attempt on making a light head. It works better than the first one.
By using the SHF205 instead off the LED's in lighthead1, the sensitivity is enormous. It is capable of detecting the light of a lighter at 40 cm.
By using a small, geared Electro motor up side down, it is possible to make it very compact without the disturbance off a lot of wires. It works very well with as less as 2,4 Volts (2 rechargeable batteries, 250 mAh). They are also mounted on the circuit board. It uses only three electronic components!

Lighthead2 circuit

First light seeker

One of my first attempts to make a light-seeker. This was made some years ago. At that time i needed a lot of components to achive a result. But then i didn't have internet. Now i'm smarter (?).

I don't have the circuits anymore.

Cricket chirper

On one of the "Internet pages" I found this nice circuit.
I have powered it by a single solar cell 24X34 mm (Panasonic) and in full sunlight it chirps all day long.
Now I want to make it work with less light by using a "solar engine".
By the way: at 3,0 V power supply it only uses 3,5 mA !

The sound is heard as far as 80 feet.



 you can't make a picture of a sound

Cricket circuit

Cricket printed circuit