browner87

(Can't find the Edit button...)
That's 6.8uF, not 8.6. Just to clarify.

browner87

Unfortunately I have made a monumentally moronic mistake. The circuit will actually require a CD4011 instead of CD4001. I was under the impression that a 555 timer started low and pulsed high, however it is apparently the other way around so the circuit will need a NOTSR latch instead of an SR latch. This means instead of NOR gates, NAND gates must be used. Since the 7400 NAND chips I have are not pin compatible with the CD4011, the best I can do right now is some schematics and diagrams if anyone can build a circuit from a diagram rather than a picture. I'll post what I have in the next day or two for people to see

99_DropTop_GT

So, no diagram?

browner87

I'm truly sorry for the wait, I know I've sort of abandoned this thread for a while now. I'm afraid the parts arrived and due to a timing glitch during the 555 startup, the circuit doesn't work yet. I am hopeful that I will be able to fix it, but I started a new job in January and I've been very busy since. I got a PM just yesterday from another forum asking for this also. Since my work hours have finally settled and I now have 3 day weekends (Tuesday-Thursday), I'll do my best to work on this during this week. Just as soon as I have evidence that my circuit will actually work, I'll post stuff for people!

browner87

The 4520 counter chips just came in today so hopefully on my next weekend (Tuesday) I'll be able to put this all to rest and prove once and for all that it's all 100% working and doable. Then I'll do some pictures and board layouts.

For anyone who happens to be fluent in circuit design, I've attached the Eagle schematic and board layout (the board layout should only be used for a rough suggestion, as Eagle only does PCB layout, not protoboard).

Please note the file says .pdf, but it is actually a .zip file (this site seems to prohibit uploading zips?). Rename it to .zip and the project files are in it. To avoid any finger-pointing, there is nothing executable in the zip, so if you need Cadsoft Eagle just download the free version from Google.

browner87

Alright now, as some of you may have guessed, I simply have given up on these for now. THEY DO WORK! I prototyped some on a breadboard and they worked just fine. However actually building the circuit and trying to explain how to do so is far too tedious.

SO. Anyone with electronics knowledge sufficient to read a schematic and build a prototype from it, I have attached schematics. As above, they are in a zip file renamed to .pdf so that I can attach it to the post. Use EAGLE schematic editor to open the diagrams (free version works just fine).

ANYONE ELSE can *try* downloading the attached file. You must rename it to .zip and inside you will find a file called GERBER.zip. These are the gerber files for the circuit boards I designed based off of the included schematics. Look in the ReadMe.txt for a fabricaton site which will ask for the gerber files. I cannot guarantee their accuracy as I haven't ordered and tried them myself, but I am fairly confident they work. If you order some and they do not work properly, look at the ReadMe.txt to contact me and I'll try to diagnose the issue (whether you made a boo-boo, or whether I boo-boo'd in the schematics). The parts you need should be easy to find on eBay (except the resistors/capacitors - I suggest buying a set of each and messing with the values to get the speed you want).


If anyone has any questions feel free to post or PM me. I hope these work well and I hope they help someone in the future. If anyone decides to build them (especially if you use the circuit boards, which I HIGHLY suggest as PCBs are SOOOOO much better than protoboard, and in the ReadMe I give a link to a really cheap place to get them made - about $13 for 10) please post results!