555 Contest Entries (Jay – FightCube)
- February 16th, 2011
- Posted in 555contest . Hacking
- By Jay(Gresko Industries)
- Write comment
555 Cradle Swing Upgrade (fightcube) (353) Schematic
- 555 SMT Timer Board Waveform
- 555 SMT Timer Board
- Headphone Tube Amp Closeup
- Headphone Tube Amp Board
Update 2:
The 555 board for the cradle swing is finished and installed. For video proof check out this link:
A schematic is also posted above.
The headphone tube amp is also finished. the high voltage for the tubes is generated by a 555 in astable mode driving a fet and a custom hand wound transformer. For video proof check out this link:
A schematic is also posted above.
Thanks to fightcube for the assistance on these projects.
UPDATE 1:
The board is assembled minus a few minor components. Powered it up, and took some waveforms. Looks pretty good. all i need is a pnp transistor or p channel fet and or a base resistor to supply the 5v to the micro. While i was at it i took some pictures of my headphone tube amp power supply. I’m not too far from being finished.
UPDATE:
I hacked the thing apart and started probing…the swing runs for 7 minutes and 15 seconds, then the lights and sounds shut off. There is a reset button that turns the lights and sound back on for another 7 minutes and 15 seconds. This has become really annoying as my daughter loves to watch the fish rotate around and the light bowl change colors all while the ocean surf sound is playing. so, every 7 minutes someone has to go push the infernal “BUTTON”. This is crazy if you are in another room or in the bathroom. So, i started probing the circuit to see what kind of signal is going to the “Chicklet” TM Microprocessor when you press the button. Turns out it is 5v. So i built a 555 circuit driving a PNP transistor. I will post the schematic later.
The 555 contest is coming, and i have decided to try and submit 2 entries…1: A 6DJ8 stereo headphone tube amp powered by a 555 switcher circuit, and 2: a simple astable timer to reset a baby cradle swing’s lights and sounds. The headphone amp is done just needs some repair-I had to disassemble it to make schematics of the power supply and the amplifier sections. The cradle swing circuit needs to be breadboarded-i have a target of 7 minutes and 15 seconds to reset the lights and sounds. I have to wait until the lights stop before i can re-trigger the switch, if i try and pulse it before then it does not have any effect. I will update this post when something changes.










Awexome Dude! Those projects turned out really well. I hope you win the free 20 sq. inches of PCB from DorkBot because I know you have more circuits in the works!!!
Next Hack!!!
Hopefully one of us will win some good stuff…I’m down for sharing my pirate’s booty with you if i win anything!
I dunno if I want to share pirate booty… maybe I’ll see if BadWolf wants to share his Bacon Booty. lol!
Congrats on getting featured on Hack A Day!
http://hackaday.com/2011/02/24/555-two-fer-baby-swing-upgrade-and-a-headphone-tube-amp
I think I’ll try to build the tube amp, but I have a few questions.
1. Why is the second grid of the 12AX7 connected to the first anode. And why is the second anode connected to the power supply? Wouldn’t this create fluctuations in the power supply itself? And what about the second cathode, which is connected to the anode of the first? This makes no sense. Wouldn’t it be better if you pass the signal from the first triode of the tube to the second(grid1>anode1>cap>grid2>anode2)?
2. What transformer did you use?
Hi,
This is what i can tell you about the design-I didn’t design it…This design is pretty old. I had the schematics since 2002. I am not sure why they are configuring the tubes like that. I agree that it seems odd. This amp it slightly unconventional in my opinion. There is no output matching transformer, it is directly coupled to the output tubes. Secondly, I did away with the bulky transformer and designed my own high freq. switching power supply. I did design that around 35k, so there wouldn’t be a lot of switching noise. It is designed around a 555 SWITCHING A FET THROUGH A HAND WOUND STEP UP COIL. I forget the ratio at the moment-maybe 15 to 1 it should be 12v to 200v. Good luck with your build.