Hello! I’m using two photoresistors to control a motor's direction based on which one receives more light. With two motors, I have it set up so the right motor spins when the right LDR gets more light, and the left motor spins when the left LDR gets more light.

I've made that using two 2N2222 NPN transistors and 2 LDRs.

Now, I’m trying to control one motor instead, where the motor spins right if the right LDR gets more light, and left if the left LDR gets more light. I know an H-Bridge or microcontroller could work, but that's not very challenging.

All my attempts have failed so far.. any suggestions?

Thanks!

 

Hi Bj,
Welcome AAC.
Post your H Bridge circuit attempt and we can check it out.
E

 

So... you know that something as simple as an H-bridge could work, but you don't want to use it because it's not very challenging. Instead, you want someone to suggest a challenging way to do something simple? Just how Rube Goldberg do you need to get for it to be acceptably challenging?

 

I know an H-Bridge or microcontroller could work, but that's not very challenging.

All my attempts have failed so far.. any suggestions?

sounds like you got the challenge you were looking for. so... why ruin it?

 

Have you tried a long-tail pair? (Google that if you don't know what it is).

 

judging by the 2N2222, this is all very low power. instead of using H-bridge, perhaps some jelly beans from the spare parts drawer could do.... like 555... lookup PWM schematics for 555 and place your LDRs in place of potentiometer. then use split power supply (or batteries) or use a pair of transistors or an amp to create virtual ground.

 

or something like this (assuming amp is able to drive your motor).

or boost it with some transistors

 

or something like this (assuming amp is able to drive your motor).
View attachment 336890
or boost it with some transistors
View attachment 336891

Thanks so much for your comment. You are really helpful!
I'm currently trying to implement your 555 timers suggestion.
And changing the potentiometers changes the direction correctly.

However, I'm trying to use LDRs, but it doesn't work.
Would you please tell me where to place the LDRs exactly?
Sorry if it's a noob question, i'm really really new to circuits.
Thanks again

 

when 555 is used for PWM, potentiometer is connected to pair of diodes.
replacing each half of the potentiometer by an LDR should create the same effect

 

when 555 is used for PWM, potentiometer is connected to pair of diodes.
replacing each half of the potentiometer by an LDR should create the same effectView attachment 336901

Where should the motor terminals be connected?

 

that would stay as is... only trigger circuit is modified.


what you are after is basically a solar tracker. there is tons of circuits for it so you don't have to develop...

 

that would stay as is... only trigger circuit is modified.

what you are after is basically a solar tracker. there is tons of circuits for it so you don't have to develop...

Lol you're right. Searched "Solar Tracker Circuit" and the first result was the solution for my issue.
I really appreciate your help, kind person <3