The Thinker Revisited


          The Thinker Revisited is an Electronic Sculpture built on an X-Ray Control circuit board. I usually salvage these boards for the parts but since I had already taken a couple of identical boards apart I decided to have some fun and see what would happen if I began to add electronic systems and some little electronic kits to it.



          The system runs on 9 to 12 volts and can be supplied with a battery pack or with an AC adapter. There are over 30 LEDs which are driven by 4 scanner kits that use a 555 timer and a CD4017 ripple counter. Each scanner is adjusted to a different cycle time so that there appears to be a random blinking of the lights. The fourth ripple counter kit is set to a slow speed of approximately 2 minutes. This counter, lights some LEDs but it also triggers the operation of some of the other kits that are installed on the sculpture. One of the kits that is triggered once each cycle is the Dice Kit. It is on the left side of the unit in the picture above. You might note that it currently displays a “4”.


Another kit that is triggered is one that plays a siren sound. This kit is in the upper left hand corner of the unit. A series of 4 slide switches allows the user to program a variety of 16 different sirens. There is a switch in the vicinity of the siren module so that it can be silenced.




A third kit that is actuated each cycle is the voice play back kit. This kit allows the user to record a voice message of up to ten seconds and then that message is played back each time the module is triggered. My first message is, “Please don’t bother me, I am thinking” in keeping with the title of the sculpture “The Thinker Revisited”.



Back of the sculpture


          Besides the LEDs on the first 3 banks of ripple counters there is a beeper attached to one LED. This beeper sounds each time the light is lit. There is a switch in the vicinity of the beeper so that it can be silenced.



          The sculpture is equipped with a PIR (Passive Infrared) sensor that allows the sculpture to see a person coming 15 or 20 feet away. When the person is detected the sculpture comes to life and starts flashing its LEDs and cycling through its’ kit program. Near the PIR there is a center off switch that allows the user to select continuous operation when the switch is up and PIR operation when the switch is down. When the switch is in the center the unit will not be on or turn on but the idler 5 volt rail remains powered.



PIR and Mode Switch


The unit also has an ear in the form of a microphone that is dead center of the top edge of the circuit board. The sound that is picked up by this microphone is amplified and fed to a VU meter on the left edge of the unit. A person can talk or sing and the VU meter will respond to the intensity of the sound.



Mic in upper right corner and VU meter on left side


          Along the top of the sculpture there are 3 voltmeters that read out the voltage on the three power rails of the unit. There is a 5 volt supply that is active any time the unit has power. This provides Power to the PIR so that the unit can wake up. There is a secondary 5 volt rail that is used to power some of the kits and a main voltage rail that carries the 9 to 12 volts from the AC adapter or the battery pack. You may note that some of the pictures have decorative frames on the Voltmeters and others don't. This sculpture is evolving and is being changed and added to as I go. It was easier to use some of the pictures that I took along the way.


          Whenever possible, components on the original board were used to provide the structure and circuit for the sculpture. The regulators for the two 5 volts rails are part of the original board layout.





          The Unit now has an Infrared proximity sensor in the lower left hand corner that can detect an approaching hand that is within 15 cm of the unit. The detection triggers a relay and a red LED on the board. The relay in turn powers a small 12 volt fan that is mounted above the infrared sensor which has 4 red streamers for extra effect. If you look closely at the picture at the top of this blog you can see that the LED is lit and the streamers are flailing in the wind.



          When I was a boy I built several “Do Nothing Machines” out of scrap electronics and parts. This is the first one of this magnitude that I have built in perhaps 55 years. This may be a sign that I have finally gone far enough over the hill that I am regressing to my childhood. In any case it was a nice escape from the stress of the Pandemic, Politics, and Civil strife of today’s world. While I have had a lot of fun with this it I didn't really know how to classify it. I am afraid the people into electronics will call it Art and the Artists will call it electronics neither wanting to own this poorly mixed child of both worlds.