Unsure how to handle power(?) issues - micro servo and Bluetooth module

am playing around with those small (9g) Micro servos as limb-actuators and have setup Serial communication to give simple commands like "Servo 1, move to 90-degree", etc. (there are really only six options, Servo 1; 0,90,180 degrees, and the same again for Servo 2)

i have run them successfully via Serial Monitor but now want to move the "limb" to the floor for more testing space - so i am now using a Bluetooth module to relay the commands wirelessly.

the schematic is simple, like so;

(EDIT: previous schematic was wrong)

the problem now is, when (it seems) a servo strains to it's lifting limit, the Bluetooth module "blacks-out" - (LED switches off - auto power-off feature ?) and one has to re-connect again.

is this just a given limitation, or is there a more efficient way of setting up the power supply for the servo and Bluetooth module ?

Thanks for any tips.

I doubt that this is the cause of your problem, but your voltage divider is connected wrong.

The node between the 10k and 5k resistor should go to the RX of the HC05 instead of GND. The other side of the 10k (that currently goes to the RX of the HC05) must go to ground.

sterretje:
...but your voltage divider is connected wrong.

The node between the 10k and 5k resistor should go to the RX of the HC05 instead of GND. The other side of the 10k (that currently goes to the RX of the HC05) must go to ground.

oops; yeah - thanks for the correction.
(drawn schematic was wrong, but actual setup is the right way)

sterretje:
I doubt that this is the cause of your problem, ...

what makes me think it is a power issue, is that without any weight, the servos function fine.

but when i start trying it out with actual weight, and exceed the servo capability, the Bluetooth module dies out.

i recently got a cheap ammeter, would that help in trouble-shooting ?
i assume the "Load to measure" would be between the Vcc and GND on the ProMini ?

You should be budgetting 1A per servo, as a first estimate, any motor or servo uses a lot of peak current.

Note that prolonged use of a cheap servo with a heavy load will simply cook it (overheat it to failure),
especially for plastic bodied ones.

MarkT:
You should be budgetting 1A per servo, as a first estimate, any motor or servo uses a lot of peak current.

wow, that high ?
i guess i should set the ammeter on them and see what the current draw now is.

the power supply (wall-wart) is only rated at 500mA but had sufficed for a simple PTZ gimbal setup.

MarkT:
Note that prolonged use of a cheap servo with a heavy load will simply cook it (overheat it to failure),
especially for plastic bodied ones.

yes, which is why i'm experimenting with them to see what the limits are, i'm using a plastic building kit for prototyping various "limb setups" - i suppose i should be calculating moments, etc but the weights of the limbs are quite light and i don't have anything that can weigh them that accurately.

looks like i'll have to find a better power supply then.