I/R Magnetic Levitator
Having found a tatty printout of an infra-red magnetic levitator circuit, i decided to build it up. The system uses 1x sender LED and 2x receive LED’s, to find the position of any item placed within the beam. The ‘error’ in balance, is what an op-amp uses for sending on/off commands to a power transistor. The transistor powers an electromagnet…the object in the beam can neither rise up to the electromagnet, or drop down to the ground when the op-amp has found the balance point of inputs. Components are all salvaged items: I/R sender LED – TV remote control I/R receive LED’s – VCR tape mechanism Electromagnet coil – steel bolt wound with 22 gauge of several hundred turns, 16 ohms 2x Neo magnets – Computer HDD (for extra lift force, works without) TL072 op-amp/red LED/1N4005 diodes/resistors/variable pots.etc – junk circuit boards Electromagnet stand – PC printer Tile base on which it all sits – kitchen tile 12V supply – PC power supply converted as bench supply (needing -12V for op-amp) Variable pots are fitted to the beam sensor input and compensation network, in case of ‘flutter’. However, having initially set the network pot to about 140K (rather than the spec 150K and then tuning to lower values if there were problems) there was no flutter and all ran without modifications. Differences in my version, to the original version. 1N4005 diodes – original calls for 1N4001’s TIP 120 – original uses a TIP 122 Variable pots – original uses fixed resistors I/R LEDS – different …