Help adding arduino/pico to photographic turntable - adding controlly motor - Page 1
Forum section: electronics / projects

author: JackDK
author_rank: Newbie
timestamp: July 19, 2025, 04:40:07 pm
content: Hello all. i would like some advice on converting this battery/usb powered photographic turntable to a RPI/PiCo/Arduino controlled turntable which i will control with python.My current thinking is to cut the motor cables and connect them to a HW-354 motor driver i have and then have this connected to an arduino or a raspberry pi zero (or pico) which i would then control via usb.the motor is 5v/2A so i currently believe that the pi/arduino should be able to power it.so i would pwoer and ground from the pi/ard then the red and black on the motor would go to the motor a (or b) holes and then two signal (gpio) connects to the in1 and in2 (or 3 and 4 if using motor b) (which i asusme would trigger the rotation of the motor?)i just wanted to check with the community that this sounds fine? would i need to add an resisitors or anything else? i also co sidered using a pico but i think it cna only output 3v which i asusme wouldnt be powerful enough? ideally the pico would fit in the void if i remvoed the current boards and i could maybe get a pi zero in there. the arudino i have is too big but i dont mind if it has to sit outsidethanks in advance for any advice!

author: Ian.M
author_rank: Super Contributor
timestamp: July 19, 2025, 06:11:07 pm
content: The MX1508 on the HW-354 motor driver is only rated for 800mA continuous motor current.https://cdn.hackaday.io/files/1960798389043936/MX1508_Datasheet.pdfDepending on the desired max. speed and turntable load, this may not be enough for the motor so you may need a beefier H bridge.Also, what are you trying to make it do? If you want more than very crude speed control and timed motion, you'll probably need an encoder for turntable position.

author: JackDK
author_rank: Newbie
timestamp: July 19, 2025, 07:09:09 pm
content: ok thanks for your advice, do you think something like this one would be sufficent. it can produce up to 2a:https://thepihut.com/products/l298n-motor-stepper-driver?variant=31985562550334&country=GB&currency=GBP&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organicalso sounds very strange but its going into a ROS2 set up where a robot arm picks and places a pinned insect that will get videos taken as it spins on place. need the turntable to rotate once something has been placed on it. doesnt need to be postion, just speed and to be able to turn on command via a pytohn command

author: Ian.M
author_rank: Super Contributor
timestamp: July 19, 2025, 07:17:51 pm
content: No. the L298N uses a bipolar output stage and has excessive voltage drop for low voltage operation. At 2A it typically drops 2V on the high side, and 1.7V on the low side leaving only 2.3V for the motor from a 5V supply, It would also need a <expletive> big heatsink!Why not start by measuring the motor current at max. speed and with your heaviest intended load off-center on the turntable? That will give you a better idea of the continuous rating your H-bridge will need. Then you'll be looking for a MOSFET H-bridge (either single IC or H-bridge driver + discrete MOSFETS) rated for that continuous current. You may want to over-rate a MOSFET H-bridge, because it may then not require any heatsinking due to the MOSFETs low on resistance.I would think that if the robot arm has to pick the object up again, unless its round, repeatable turntable position when stopped will be important so it is appropriately oriented to grip. OTOH if you have good enough machine vision on the arm's gripper and enough degrees of freedom to can adapt to any orientation, you may not care.