Lets now start of with a new series – “Hobby DIY Electronics” which contains small projects to start for beginners, robotics and much more. Enjoy the series of upcoming posts and do leave your experiences and messages in the comments section below.

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Making Bibberbeests with kids is a HUGE success at schools, parties and festivals

Now what is more fun than a Bibberbeest? A remote controlled bibberbeest, using a standard audio/video RC?
So what I needed was a receiver circuit for a standard TV RC that can switch on and off a Bibberbeest’s motor, working on 3 Volts max.

At first I was tempted to go the microcontroller way, But in my eternal search to keep things simple, I eventually decided to use a hardware-only circuit: Just eight parts on a 2,5 x 4 cm board (1″ x 1,5″).
After some trial and error I used this IR toggle switch diagram (with slight mods) around a 555 timer chip by member BIC, which works quite well.

Step 1: Tools and materials

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Apart from the stuff needed for a Bibberbeest, you need the following for the circuit:

Breadboard for prototyping
Jumper wire

Battery holder for 2 AA cells in series
Two pairs (male + female) wire connectors

1 IR receiver TSOP 38238 (to pick up the 38kHz IR signal from most audio and video RC’s)

Logic IC:
7555 low power timer chip (needed because I want to use a max of 2 AA batteries / 3 Volt)
8 pin IC foot

Transistors:
1x BC547
1x BC337 (to drive the bibberbeest motor)

Capacitors:
1x 0,1 uF
1x 1uF
1x 10 uF

Resistors:
1x 18kOhm

Strip board to mount the circuit on, about 4 x 4 cm (1.5″ x 1.5″)

Batteryholder, IR receiver and logic IC cost a bit less or more than €1. The other parts are much cheaper. The total circuit is around €5,- I think.

Tools:
Soldering iron and solder
Small saw to cut out the strip board
Small pliers
File to smoothen the board
Multitool / small screwdriver

Step 2: The circuit

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The circuit is pretty easy to make: Just 10 parts and a decent lay-out.

The circuit works as a push-button switch: As long as any of the RC’s buttons are pushed, the motor is turned on. Release the RC’s button, the motor stops:

The circuit still is a little over-sensitive to stray IR light. Covering the IR receiver with a small tube made of a strip of plain paper works remarkably well.

(I’m still working on an electronic way to filter out stray IR light… It can be done!)

Step 3: Prototype it: Breadboarding

 

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Just to make sure you understand the circuit, make it on a breadboard first. It will take about 30 minutes and gives back confidence in return.

To test the circuit, I soldered two wires to the motor, and male connectors on the tips.

During testing, the motor briefly switched on, without a “command” from the remote control. This is caused by ambient infrared radiation. I’m still working on an electronic filter to block the ambient IR, but I also found another, very non-electronic way to filter ambient IR out:

Cover the IR receiver with a small tube of plain paper! Just cut a strip of paper and roll it into a tube and close one end. This paper tube blocks a fair amount (but not all) ambient IR light.

 

Step 4: Build the circuit: Soldering!

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Cut a piece of strip board, 9 lines, 15 columns.
Smoothen the edges with a file or smooth sanding paper.

Cut the copper strips on the X-marked spots with a 4.5 mm drill bit. Check the cuts with a loupe.

Start soldering the components. I used blobs of non-hardening clay to fix the parts before turning over the board to solder the leads.
Start with the lowest parts (the jumper wire). Then the resistor and the IC foot, then the rest. Solder two female connectors in the holes marked with a circle.

One jumper wire must be mounted over the BC337 transistor.

Step 5: Mount it on a Bibberbeest

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You’re there! You just made a brain for a Bibberbeest, giving it a sense for ordinary remote controls. Next step is of course to become Dr. Frankenstein, placing the brain into (onto?) a self made Bibberbeest.

To mount the circuit on a bibberbeest’s “spine” (a strip of connectors), I made a pair of straps with 16 Amp solid core wire

The battery holder is fixed to the connectors using double sided foam tape.