I built this circuit:

However, I am unsure about which orientation the four photodiodes should be placed in, and which motors to connect them to. Is it just guess and check?

 

I guess you got the schematic from this page:
http://www.solarbotics.net/library/circuits/bot_head_pshead.html

Unfortunately, much of Wilf's work was lost when Geocities closed.

You might be able to read some of it by using the Wayback site.

 

I built this circuit:

However, I am unsure about which orientation the four photodiodes should be placed in, and which motors to connect them to. Is it just guess and check?

for one, if you look at the schematic it has labels for the Anode and the Cathode of the photodiodes, these circuits are normally built "dead bug" style, so the connections you see in the schematic is the actual layout of the circuit, if you connected everything as shown, there should not be a problem determining which motor is controlled by what pair of photodiodes...


My .02

 

for one, if you look at the schematic it has labels for the Anode and the Cathode of the photodiodes, these circuits are normally built "dead bug" style, so the connections you see in the schematic is the actual layout of the circuit, if you connected everything as shown, there should not be a problem determining which motor is controlled by what pair of photodiodes...


My .02

See your .02 and raise .03.

 

I did see that - do I arrange the photodiodes exactly as shown in the schematic? (in that box pattern) That is what I have done and the results are finicky. A more logical setup would be to criss-cross them, but the schematic had no mention of it so I just built it as shown.

So should the photodiodes be arranged differently - say the four cardinal points - the tilt motor diodes should be on north and south, and the pan motor diodes should be on east and west? The current configuration I have is that the tilt is on one side and the pan on the other (which doesn't really make sense now that I think of it)

 

I just ran into Wilf Rigter's 2 DOF SPSH plans, like maybe 2 months ago (I know, I know, Johnny come lately) and have just now come around to building it (time permitted) and didn't get it to work but reading these posts I think I may be building it wrong. Deadbug style is when the pins are facing up, correct? because in the [2 DOF SPSH] diagram, I was under the impression that the viewer was looking down on the top side of the chip, specially that the chip has that written on the right hand side of the diagram (looking down on the diagram, that is) but then again the diagram doesn't indicate pin 1, either. So mijne should work whan i turn the chip upside down and solder everything up?

 

I just ran into Wilf Rigter's 2 DOF SPSH plans, like maybe 2 months ago (I know, I know, Johnny come lately) and have just now come around to building it (time permitted) and didn't get it to work but reading these posts I think I may be building it wrong. Deadbug style is when the pins are facing up, correct? because in the [2 DOF SPSH] diagram, I was under the impression that the viewer was looking down on the top side of the chip, specially that the chip has that written on the right hand side of the diagram (looking down on the diagram, that is) but then again the diagram doesn't indicate pin 1, either. So mijne should work whan i turn the chip upside down and solder everything up?

No, these circuits are built dead bug style, but the circuit in the above post is shown from the top view (as it says in the diagram). Pin1 on the IC is usually to the left of the small dimple in the top of the IC, (shown also in the diagram).

 

long read/first post

I too went ahead and hastily built a 2dof using the same schematic. Dead bug style as well (don't worry, no confusion about orientation). I'm also not getting any results. which leads me to believe either I somehow bought the wrong stuff or maybe I should have prototyped the circuit on my solder-less board. I'm using the 74ACT240 chip because I couldn't find the AC at my local store and I was too impatient to order one. I also picked up a 74AS240 but I cant remember why. Also using those purple LED photodiodes. I can get voltages from both the diodes and the solar cell (3V) but I'm not getting an movement. I have a 10000uF 16wv cap attached to it like in the circuit.

I assume I will have to disassemble it, salvage what I can, and but it on a circuit board and then start testing but my question is...

Does the Cap have to "fully" charge before it starts working or should it work immediately from the time i finish my last solder and pop in the chip?

Also the motors I bought were 1.5V each and I have no idea how I want to mount them. Any suggestions.

Sidenote: I wanted to eventually replace the PDs with piezos and mount the entire thing in a large bobblehead so that it becomes a very creepy/paranoid booblehead that will occasionally follow a conversation. Will the circuit be the same or will I have to replace some resistors?

 

Oh, my thread is revived! Anyways when I built mine, I built it on a IC socket so I could remove the chip just in case. It works great:

 

That looks great, small, and clean. mine looks very much like a dead bug that exploded. I used an IC socket as well. sorry for the big pictures.
I still don't know why it isn't working. any thoughts? also what motor and mount did you use? is that laser cut?

 

I used some gearmotors from BG micro, I saw a nice 2dof beam head on youtube that used those motors so I tried to copy it. Yeah everything is laser cut out of hard paperboard:

What are the specs for your solar panel? The one on mine in the pics is rated at 3v 100ma and even that was too small and it would struggle, right now I have a 6v 200ma that should work.

I would just look over the circuit/rebuild it just to make sure everything is wired up correctly, but it looks like the tiny solar panel is the problem.

 

I still don't know why it isn't working. any thoughts?

For one, if I am not mistaken, you used IR LED's as your photodiodes, IR LED's usually are colored like that, photodiodes, phototransistor's, and other IR detectors are colored almost black, or with a dark tint to help block out ambient light, some have built in daylight filters and such...... Do you see Razor Concepts photodiodes????

shown in the pic is an IR LED (light blue), and a 3 pin phototransistor.....



My .02

 

I used some gearmotors from BG micro, I saw a nice 2dof beam head on youtube that used those motors so I tried to copy it. Yeah everything is laser cut out of hard paperboard:

What are the specs for your solar panel? The one on mine in the pics is rated at 3v 100ma and even that was too small and it would struggle, right now I have a 6v 200ma that should work.

I would just look over the circuit/rebuild it just to make sure everything is wired up correctly, but it looks like the tiny solar panel is the problem.

I found these at Solarbotics once (They don't seem to carry them anymore, they replaced them with some bigger ones with the Miller SE engine circuit on the back ) Anyway, these are approximately 1" sq. put out 5 volts in direct sunlight..... works real well for a 3 volt solar popper



B. Morse

 

I took the panel from one of those outdoor garden lights that you get for $4 at Walmart. I got 3V under direct light but around 1-2V in ambient light. I don't remember what I rated the current at. I picked it up because I thought it would be strong enough and was cheap. I guess I should look at something rated for 6V to be sure?

I didn't realize I was buying the wrong thing. I got them from my favorite surplus store and they were in a bin labeled "photo diode" I should have asked someone if I wasn't sure. Also is it possible my motors are too big? They were sold as 1.5V each. Is that too power hungry?

Thanks for all the help.

Any thoughts on the bobble head idea? Or is it just stupid.

 

I finally got my powered smart headbot to work, (note it's not a solar powered one) and here how I'm putting it together. You can see the evolution of the "brain bug" from bread board to brain bug, to bot with brain bug, another model will be built using a 6 volt solar panel, it seems to work best for the namiki gear motors (100:1). I am trying to condense the brainbug and batteries into the robpot as to hide. More pics and vids to come. Thanks BMorse for your bit of help.

 

Thanks for the help. Razor Concepts, that base looks amazing. I ordered the 4.5V soalr panel on Solarbotics hopping it'll be enough, along with some other bits and pieces. Yea that 6V panel has been on backorder forever. I also picked up some of that 2mm plastic sheeting and I might just try and mimic your design. How did you connect the supports to the motor shaft, I couldn't find anything small enough to screw into or clamp on my motor shafts so I was thinking hot glue or Goop.

 

I used a 2mm prop saver for RC airplanes, screwed that on though the paper board and made a little paper board clamp.

 

So I went to my local shop and pulled 2 sets of leds. The clear one was from the phototransistor box, and the darkest one from the photo voltaic transistor box. An then of course the IR leds that I had bought previously. The the clear and darkest one remind me of the IR emitter and detector sets from radioshack, so I plugged the appropriate battery and resister in to the clear on but I got no response. But testing the IR leds the same way and I got a signal. (I used a digi cam to see the light). Is the one labeled photo voltaic the one that I want? Are these box labels misleading and/or confusing me? Other than swapping them out directly is there any way to tell whether or not I bought the right thing, and if not, what did I buy? Thanks for the help in advance. Bright side is that I'm going to use 2 of those IR leds for a wii bar.

 

If you have a DVM that has a setting for diode testing then you may be able to get a reading that tells which ones are diodes and which ones are not.

hgmjr

 

I don't think I do. I guess its just trial and error once I get the right solar panel in the mail.