Request for troubleshooting assistance.

[Boogity]

Last summer I designed a chicken coop door opener and the electronic control board. Mechanically it works very well but my control board has a problem. I think it's called phantom loads. When the door reaches the stop point (either up or down) the limit switches open the motor circuit. But, due to my design, the relay and other electronics still draw current in the "hold" mode. I'm sure there is a simple solution to my problem but I cannot come up with one. Luckily I still have my breadboard from when I was in the design stage last year. I found it in my shop buried under junk.

I use a solar charger to keep a motorcycle battery charged because there is no AC power to the chicken coop. My circuit design drains the battery because the relay and other electronics are powered in the "hold" mode.

Since I made my door I have had a stroke and I'm slightly physically and mentally challenged. So as i go through my old diagrams and look for a solution I get very confused. You guys would have a good laugh if you could see how my body reacts to confusion these days. I shake all over. Typing this stuff takes me forever, too.

Anyway, I have scanned my diagrams and would like to email them to anyone who would be interested in reviewing them to see if we can come up with a solution. Watcha think?

 

[duffy]

Don't email - upload! Electro-tech has a wonderful feature that allows you to upload images from your hard drive. Click on the little picture icon over the reply box, click "from computer", click "browse", and then select the file off your drive.

 

[Boogity]

Don't email - upload! Electro-tech has a wonderful feature that allows you to upload images from your hard drive. Click on the little picture icon over the reply box, click "from computer", click "browse", and then select the file off your drive.

OK let's give this a try.

As you will see (I hope) on the diagrams the limit switches open the power supply circuit to the motor but the power supply to the relay is on at all times. Let's see if we can power down all components that are not necessary for the function of the photo cell.

The pictures are of my breadboard. The first breadboard pic is with the photo cell "seeing" sunshine and my LED is green meaning that the motor circuit is in the up position. The second pic shows my finger over the photo cell and the LED is red meaning that the circuit is in the down position.

Thanks all.

 

[user_88]

... analysis of the problem

Where in the circuit are the main currents that drain the battery?
It seems likely that one current path might be responsible for most of the battery drain.
The photo-resistor might contribute about 2 mA during full light exposure, much less when dark.
Other possibilities are through the 11 and 6 terminals of the K1 relay, the path through the T1 transistor ... measured from the emitter to ground, or possibly the LM311, measured between the 1,4 terminal junction and ground.
The 100 kΩ resistor should be only about 0.12 mA ... probably not significant.

Do you have a current measuring meter that would allow you to find the current values mentioned here?

 

[alec_t]

The main current drain here is the relay. It could be replaced by a latching relay or by a solid-state H-bridge (preferably using FETs). If FETs were used then all resistor values could be increased. The comparator could be replaced by a CMOS Schmitt gate.

 

[user_88]

... referring to this diagram for the comparator operation:
**broken link removed**

It looks like when the photo-resistor is non-conductive ... at night ... the comparator output is in the off state, which would create a high LM311 output voltage, which would turn the T1 transistor on ... which would last all night long.

The night-time on state of T1 would discharge the battery during the time when there would be no solar recharging.

It might help significantly if you were to find out how much current flowing through T1 is minimally required to turn on the K1 relay coil. At the present time, there is no limiting resistor in the T1 current path, other than the intrinsic resistance of the relay coil winding. A 1k current limiting resistance inserted at the collector of T1 might be all that is needed to bring the design to within some sort of reasonable operating parameters. If 1k Ω is too much, try 500 Ω, 250, or 100. Does the T1 transistor feel hot to touch when it is on? If so, it could definitely use some additional resistance in its collector to emitter path.

edit ...
Was going to say try switching the + and - connections to the LM311, so that T1 would be turned off at night, but not sure that would work.
... Don't think I completely understand the motor and door cycle operation at this time.

 

[ccurtis]

Delete Post

 

[Boogity]

Hey everyone - thanks for the replies. Right now my head is spinning with all the information I received. I just wish I could understand things like I used to. Maybe this is too advanced for my in my condition. I got out my multimeter today and I cannot figure out how to measure current usage by the components. Whew! What ever you do, don't have a stroke. As if we have a choice.

I'll try to dig into this tomorrow when I'm (hopefully) having a better day.

 

[Sceadwian]

Any day you try to learn more is a testament to your strength. I think I speak for all members of this forum in that respect, if there is anything we can do let us know. If it's too much again let us know, we want to hear from and help you if we can.

My best thoughts on your recovery, make sure you have fun!

 

[alec_t]

My best wishes too for your recovery.
When you're able, perhaps you'd like to consider the attached option. Its average current drain when the motor isn't running is only ~ 94 μA !

 

[duffy]

^ Say, that sure looks like the answer. The down limit switch shuts off the relay (so it doesn't drain power) and the mosfet shuts off the motor (so it doesn't run backwards when the reversing relay drops out).