RC Circuit for a Bibberbeest / Vibrobot

I completely lost control of my vibrobot project "Scary bots and Super Creeps". The creatures are named "bibberbeest" in Dutch and kids from 6 Yeats and up LOVE making these. So much, that I decided to create kits and sell them separately as a present, or in a set to schools: Have a look at my webshop if you're interested.

Making Bibberbeests with kids is a HUGE success at schools, parties and festivals (second video in this step)! During festivals and at schools I witnessed hundreds of kids making their very own, unique Bibberbeest.

So I had to think of a follow-up: What can be equal to or more fun than a Bibberbeest? A remote controlled bibberbeest, maybe? controlled by a standard audio/video RC? And it makes the project a bit more challenging to high school kids like monster-marit and emilyvanleemput :-)

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, inspired by Masynmachien's Wiebelbot. 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.

(I updated this Instructable on Sept. 6th. Before that date, I used a different circuit which was more sensitive to ambient IR light).

Last summer I spend 4 afternoons on a festival, making Bibberbeests / vibrobots with kids. If you're into it: It's a great project to do with kids! They love the creatures they make, and the easy to handle tools and materials enable the kids to make their very own, very personal Bibberbeest.

Tools and Materials

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.

One-stop shopping at Radio Shack, Conrad or Farnell.

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

The Circuit

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!)

Prototype It: Breadboarding

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.

Build the Circuit: Soldering!

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.

I didn't build this circuit on a PCB yet. The bibberbeest on the pictures and in the video is wearing a previous version of the circuit (posted in the final step of this Ible...).

Mount It on a Bibberbeest

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. For that, you skip to this Instructable.

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 (see pic 1).

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

Improvements...

As always with electronics, there are a million ways to get to the desired functionality. So a new version of the circuit could contain:

A microcontroller, controlling several motors on a Bibberbeests separately.
I want to give the circuit in picture 1 a try. It doesn't contain an IC and uses an analog filter to pick up the 38kHz signal from the RC, ignoring any stray / ambient IR radiation.

The use of a microcontroller pushes up the level for kids. So I also want a version for kids 8 - 12 years that can be soldered on a piece of wood, using copper pushpins to solder the parts on.

If you have any ideas about anything of the above, please leave a comment. It'll be highly appreciated! Thanks for reading.