I have built Randy Underwood's Christmas Tree?

[tnux]

Hello all;

I have finally completed the light tree with a few modifications and it works very well.
It is operated from GPRM and it operates the start gate.
Here is a link to view it on u-tube.


https://youtu.be/9E--Mpjf-C8

Happy Racing and God Bless to all

Tom N

[John Shreffler]

Ground is ground the world around. Of course connect the grounds.

[tnux]

Thanks John,

I'm sure I've heard that before some where but I don't work with electronics enough to remember these things.

Say a prayer and wish me luck.

If it works, I'll ne sure to post some pics.

[tnux]

Hello All;

I finaly got it to work!
Apparently,, the 4069 chip must have power and ground. This was not shown in the print.

Bad thing is I've been using the same start gate that is in this plan for several years but the tree won't trigger it.

Well,, Hopefully I'll find a solution. Otherwise We'll just trigger the gate manuely.

I'm sure with a little hope and a lot of prayer and maby some help from someone out there, I'll find a solution.

God Bless
tnux

[John Shreffler]

umm, I think you meant the 2003 needs pwr and gnd. Question: Are you joining the commons from the Light Tree to the common of the solenoid?

[tnux]

umm, I think you meant the 2003 needs pwr and gnd. Question: Are you joining the commons from the Light Tree to the common of the solenoid?

umm no and yes. The Print shows Pwr & Grnd on the 2003 so I did connect it. The 4069 Only shows signal from the timer through one NOT chip to the 4017, no connection to Pwr or Grnd on the 4069. After I made this connection the tree works.

[quadad]

Interesting - the ULN2003 type device was used in my first project decades ago and it is still quite useful today !! AFAIK it really has no power connection though. Pin 9 is a diode common pin to limit maimum voltages when driving devices with some stored energy kick (i.e. relays). It can be connected to your positive voltage source when used for those loads (not done in Randy's circuit though). Pin 8 on this device is the real (earth) ground connection that you need to make. It always helps to breadboard a circuit first, even when you are handed a circuit diagram - I use a plug-in proto board for doing this which is real quick (another decades old invention).

[tnux]

Hello and thanks quadad;
I found the same info on the 2003, ie. pin 8 is grnd. Its a set of darlington transistors with protection diodes built in. To be honest I do but just barily understand how this actualy works. I know that there should be diodes to protect the transistors from the relays, but I wasn't sure how to hook them up. Actualy I thought that they allready were but you mentioned to connect the pin 9 common to v+. Is that correct so as to give better protection to the transistors?
I have decided to forgo the led lights as I couldnot find a good method to display the lights that I liked. So, I decided to go with relayes and flood lights. It will definatly look more realistic and cool I think.
One more note I wanted to mention, the output connection for the start gate on the 4017, pin 10 or Q4 out does not give suficient current or time to trigger the start gate. I finaly decided to connect the start gate to the pin 3 out of the 4071 as this holds the green light on for 3+ seconds. more than enough to trigger the start gate and the circuit seems to work just fine. I mean did not notice any change in the light sequencing before and after I changed the SG connection.
Hope this may help someone out there.
As I am getting so close to actually completing this project. I will definetly post some pics in about a month or two.
God Bless
tnux