bob_moody Posted May 18, 2010 Posted May 18, 2010 Okay, this may be a galactically stupid question but here it goes anyway.I am working on hacking my Gemmy Santa to run off of LOR. I do have it working now simply by removing the Gemmy "Mystery Chip" and using a set of reed relays to fire each of the 4 controls (Dance, Mouth, Head Left and Head Right).The reason at this point for leaving all the Gemmy circuitry intact is the head movement. It takes a positive voltage to move the head one way and a negative voltage to move it back the other. This is currently handled by the Gemmy board.What I would like to do is remove all the surplus electronics and drive the servo's (not really servo's but little motors) directly with the DC LOR board.At the risk of being laughed off the board, can I simply reverse the connection polarity between the LOR board and the head movement to get the negative voltage head motion? (Positive to Negative and Negative to Positive)This would really simplfy the project.Thanks for help (Please laugh kindly and with good spirit)Bob
J_Plak Posted May 18, 2010 Posted May 18, 2010 Hi Bob,this may helpBrief H-Bridge Theory of Operationhttp://www.dprg.org/tutorials/1998-04a/Building the H-Bridgehttp://www.mcmanis.com/chuck/Robotics/tutorial/h-bridge/bjt-circuit.html6-transistor H-bridgehttp://library.solarbotics.net/circuits/driver_tilden.htmlJerry
Geoff Harvey Posted May 18, 2010 Posted May 18, 2010 BobI would be reluctant to try this as all the LOR DC board +ve connections are common, ie shorted together on the board, so the board cannot supply +ve/-ve outputs either side of a common voltage.I have no idea of the Gemmy circuitry, but maybe you can feed some signals to activate the existing circuits.Regards Geoff
LightORamaJohn Posted May 19, 2010 Posted May 19, 2010 bob_moody wrote: At the risk of being laughed off the board, can I simply reverse the connection polarity between the LOR board and the head movement to get the negative voltage head motion? (Positive to Negative and Negative to Positive)If the motor is wired separately (no wires in common with other motors) then I think the simplest solution, if you don't want to use the Gemmy board, is a DPDT relay. In the attached schematic, channel 1 controls the speed of the movement and Channel 2 (always fully on or off) controls the direction. These are available at RadioShack. Attached files
bob_moody Posted May 19, 2010 Author Posted May 19, 2010 Here is an excerpt from the guy who published the hack regarding the control for the head motion:"RED/PURPLE pair: This controls the left/right movement of Santa's head. Unlike the other connections, the red wire will carry + or - 5 volts, depending on direction. With 0 volts, the head stays in its current position. The purple wire is used for ground."So an H-Bridge should do the trick (?)Bob
Vic Fortenbach Posted May 19, 2010 Posted May 19, 2010 There seem to be some confusion on how to make (the Gemmy) Santa's head move. The hack that I have almost completed for Bill Hoffman, I used the same circuit diagram that LightoramaJohn posted. The motor inside the head is a single motor with two wires, reversing the wires moves the head in the opposite direction. The motor is a 12 volt motor. The only major problems I had was motor noise. A small .01 mf capacitor across each motor solved the noise problem. The Gemmy board has the capacitors on board, but since I did not use the Gemmy board, I had to add the caps.I could never get the Gemmy board to work with out its "mini controller board/module", so I scrapped the Gemmy board altogether and used a Dasher board for interface (LOR interfaces to the Dasher board quite nicely). I still have to add an audio amp to Santa, so any singing comes from Santa and not a speaker behind him.
bob_moody Posted May 20, 2010 Author Posted May 20, 2010 Hey Vic,Actually the only way I have the thing working (at the moment) is with the Gemmy main board (sans the magic chip).I found the points on the board between the magic chip and the main board and by applying 5vDC to the appropriate spot I have control of the functions. I didnt need the start button or any of the other outside functions. BUT... I did need the power supply.You are right. There is only the one pair of wires from the head motor and I think LightoRamaJohn's drawing would work like a charm.Shouldnt be that hard to program either just a liitle awkward in that you dont have a limit switch to discon power when you reach full left or full right and there isnt a return to center.Bob
DaveK Posted May 20, 2010 Posted May 20, 2010 Here is a slight modification to LightORamaJohn’s relay schematic.Channel 1 is one direction and Channel 2 is the other. There could be a very slight delay in the motor starting as the relay is activated, and Vic’s suggestions of a capacitor to reduce noise and dissipate the spike as the relay and motor are switched off is needed. But with this wiring it doesn’t require two LOR Channels to be simultaneously on to reverse the direction.I am not an electrician or engineer, just a hobbyist. So comments, suggestions and critique are welcome. Attached files
Vic Fortenbach Posted May 20, 2010 Posted May 20, 2010 Bob – Now that you have mastered the hardware. You will need a good song for Santa to sing, I found a CD called "Santa Sings". It's an import from England, so Santa has a slight accent. I used the song, "Is this the way to Santa's Grotto (Amarillo)".Below is the link to the website that you can purchase the song, as well as hear some song samples. I was looking on Amazon.com and there is now a second "Santa Sings" CD that may also work, but I have not tried it. Just search "Santa Sings" on amazon.com.http://www.hyperlaunch.com/santasings/
Vic Fortenbach Posted May 20, 2010 Posted May 20, 2010 After clicking on the links I provided above, I found they don't work.Here is the link to Amazon.com in the UK that has the CD.Amazon.com in the USA does not have it.http://www.amazon.co.uk/Santa-Sings/dp/B000BU2D7MSorry for the confusion
bob_moody Posted May 20, 2010 Author Posted May 20, 2010 I dont know about "Mastering" the hardware , but I do have an update on things.So far the only issue was with a mis coded wire pair. On my Santa, the Black/White pair is the mouth not the speaker and the pair that was the speaker is the mouth (DUH)....Anyway ... a simple power supply test has verifed operation and either John or Dave's relay schematic should put it over the top.Only issue now is voltages. The dance and mouth seem to operate fine at 12Vdc, but the head is WAY to fast and hits way to hard when it pegs the stops. I may just have to add a 12Vdc to 5Vdc circuit to drive the head and let the rest run on 12V...I'm going to test everything at 5Vdc and see .. it may just be easier in the long run.(I also have about 100 Contenental 3 - 32 VDC SSRS that I can use for other things on this DC board .. so running at 5Vdc isnt a problem. In other words I dont have to burn a whole LOR board for 4 channels. I can use the SSR's on the other 12 channels... UNLESS I buy the DIO32 (drool) ... then the possibilities are endless...)Bob
LightORamaJohn Posted May 20, 2010 Posted May 20, 2010 bob_moody wrote: Only issue now is voltages. The dance and mouth seem to operate fine at 12Vdc, but the head is WAY to fast and hits way to hard when it pegs the stops. I may just have to add a 12Vdc to 5Vdc circuit to drive the head and let the rest run on 12V...If you've wired it as I showed, try reducing the intensity of channel 1 to slow the motor down. If this works, you could use a fade down to move the head left or right to reduce the impact at the head's limits.
Vic Fortenbach Posted May 20, 2010 Posted May 20, 2010 The LOR interface opened up many new ideas, one idea I had and use (it works quite well) is varing the motor speed. Not by just reducing the voltage, but pulsing the signal. On the LOR sequence screen, I just made lots of little (I think .01) timing columns. I only filled in every other one, this will slow down the motor speed. The head turn will appear jerky if you swing it full left or right, but small movments or "side to side" nods look great.One thought, if you use 5volts, the hip motor may not work due to its start up torque to swings Santa's hips.Never mind, LightORamaJohn replied the basicly same idea above.
bob_moody Posted May 20, 2010 Author Posted May 20, 2010 Well you guys just answered my next question which was could I control voltage with intensity and I really like the pulsed idea for moving the head. A low intensity on the head and pulsing it may just do the trick... makes programming a lot of fun..LOL .. but I think it would out better..As for the overall voltage.. I did try the hips and mouth at 5vDC .. not really a winner there. The hips sway a tad fast at 12Vdc BUT .. if I knock it down to say 75 or 80 percent I may have a little better swing (Remember that the Gemmy board had that little variable resistor.. the one with 2 green wires.. to control the speed of Santa's hips... without it... its full blast at 12Vdc)Also the mouth really needs 8 to 12Vdc to work crisply ... he wont even open at 5Vdc.Bob
Rafter Bar R Posted May 21, 2010 Posted May 21, 2010 Thanks for posting the solid state H-bridge circuits, I have found some LED's that these will work with.
Recommended Posts