The instructable describes how to make small stroboscope, which can be used for home parties, dance nights, birthday celebrations..etc. The stroboscope uses parts, which can recycled from disposable photo cameras and high efficiency bulb lamps. It needs only some additional parts, which also can be recycled from some defected or unused electronic devices. The stroboscope has a knob, which can be used for the setting of the time interval between the flashes (the flashing speed). The work of the device can be seen on the linked video.
Step 1: Security Warnings
This device is supplied by high AC voltage taken directly form the outlet. This voltage can appear on each internal node. The rules for work with high voltages must be followed during testing, measuring and use!
Some important principles to be considered:
- If the device is not paced in a plastic isolating box it must be always put on insulating (plastic, wood, rubber surface) when supplied.
- When supplied none of the parts of the device or the PCB should be touched by hands or should be in contact with conducting materials
- The device should be mounted in plastic case, and no metal parts shall be accessible outside the box
- For the regulation potentiometer is advised to be used such one, which has plastic shaft
- When some works on the device have to be performed, it is required, that the PCB can be accessed minimum one minute after disconnecting it from the outlet. This will allow the internal capacitors to discharge to values, which are safe.
- All measurements of the internal voltages of the device nodes should be performed very carefully and only after fixing the device strongly to prevent any sliding and consequently short connection
- All other rules considering works with high voltages!
Step 2: The Parts
The main part of the stroboscope - the flash bulb was extracted from a disposable photo camera. The high voltage triggering transformer was taken also from there. On the same PCB can be found also some usable capacitors and transistors. The rectifier high voltage diodes were taken from the disassembled defected high efficiency lighting bulbs. The diac can be found also on this PCB.Additionally we need 10W 820 Ohm resistor, thyristor, some resistors and capacitors.
Step 3: The Curcuit
On the first picture can be seen the circuit of the device. There you can see the parts used.
I have mounted all parts on the small single sided PCB produced by the toner transfer method.
You can use the second picture for that purpose. Because the device does not contain any chips with fixed pin pitch, the PCB size can vary in some limits. The size determining of the PCB can be the pin pitch of the HV transformer, or the size of the 10W resistor, or the pin pitch of the potentiometer. You can mirror the picture, or use it as it is. Be careful with the pins of the triggering transformer.
The placement of the used parts is shown on the third picture.
Depending on the size of C3 - it can be soldered between points 1 and 2 or 3 and 4. The other two remaining points should be bridged by a wire.
The fourth picture shows how the HV transformer is connected to the flash bulb - its HV output is soldered directly to the metallic shield placed around the flash bulb.
Step 4: The Assembled Device
All devices soldered on the PCB can be seen here. The flash bulb and the PCB are fixed by the use of hot glue.
On the second picture can be seen the whole assembled device.
This stroboscope was produced and tested in Europe, where the AC voltage is 220V. In USA it could work also, but may be some modification would be necessary - for example the voltage divider R3,R4 must be changed - R4 increased, R3 reduced. R4 could be even omitted.
In the device can be used other semiconductor parts - other available thyristor which can sustain 300V, other diac.
In some cases instead the diac a simple glow tube can be used.
Once again - the device must be placed in insulating plastic case!
Normally, if all used parts are functional, the device starts to work immediately after assembling. The frequency of the flashes can reach 10-20 per second. It is possible that after long use the flash bulb fails. I would recommend to use some connector for the bulb, which will allow fast replacement.
Thank you for the attention, and good luck in the play!