hi all
I've just knocked up a circuit based on the 555 IC. The circuit works fine except for the limited throw of the servo arm. To get over this I have changed the variable resistor of the circuit from the 10K specified to a 50K pot. This has increased the throw brilliantly From less than 45D total with the 10K to a massive 140D with the 50K. Now only the first half of the pot actually operates the servo so from 0ohm to approx 20K (measured with a meter). It is proportional in response but I need it to operate either side of the pots center. Am I correct in reasoning that I should now purchase a 22K pot (nearest value) and this would then function either side of it's centre. I.E. 11K each way. Or do I simply need to adjust R1 and R2 of the circuit to get the 'around centre' response? I intend to build the circuit to drive the eye-stalk of a dalek using the 14Kg torque servo I'm currently testing the circuit with. I intend to scavenge and modify the gimbal from an old RC radio transmitter to control it by fitting the servo drivers pot in place of the one thats already on the gimbal. Answers to both options would be gratefully recieved.
Regards
Fenris
I've just knocked up a circuit based on the 555 IC. The circuit works fine except for the limited throw of the servo arm. To get over this I have changed the variable resistor of the circuit from the 10K specified to a 50K pot. This has increased the throw brilliantly From less than 45D total with the 10K to a massive 140D with the 50K. Now only the first half of the pot actually operates the servo so from 0ohm to approx 20K (measured with a meter). It is proportional in response but I need it to operate either side of the pots center. Am I correct in reasoning that I should now purchase a 22K pot (nearest value) and this would then function either side of it's centre. I.E. 11K each way. Or do I simply need to adjust R1 and R2 of the circuit to get the 'around centre' response? I intend to build the circuit to drive the eye-stalk of a dalek using the 14Kg torque servo I'm currently testing the circuit with. I intend to scavenge and modify the gimbal from an old RC radio transmitter to control it by fitting the servo drivers pot in place of the one thats already on the gimbal. Answers to both options would be gratefully recieved.
Regards
Fenris
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