Hi guys, I’m trying to build a wireless robot that can be control from my pc through hyperterminal. I’m using a bluesmirf modem for wireless communication, an atmega8 for logic control, sn754410 h-bridge and 74hc04 hex inverter for motor control. The atmega8 and bluesmirf work fine together and the atmega8 works fine with the h-bridge circuit. However when I connect all 3 it start out ok, I send one command to make the motor goes forward and it works but when i send the command for it to reverse the motor, the bluesmirf shuts down. I’m not sure what is goin on. This is the schematic of the cicuit i have.
I dont know if this makes a difference but here is how i set it up. Mounted on a breadboard is the bluesmirf and a 5v regulartor. The atmega 8 is on its own pcb and the h-bridge is on its own pcb. The H-bridge circuit is on its own pcb(home made). Can anyone please help me with this. Thanks.
Yes right now I’m testing it with a power supply but eventually I will be providing the power with 6 rechargable batteries(aprox. 7.2v). From the power supply i’m giving the circuit 7v. Everything in the circuit receive 5v through the regulator and 7v goes directly to vcc2.
Thanks baravi for hinting at it. Turns out i’m not giving the whole thing enough juice. I up the power supply to 9v and it ran ok. I just thought that 7v would be enough but i guess not. I think my robot in the end will need 12v total.
It is not generally not a good idea to be using the same power source for the motors as well a your electronics. When the motors are switched on, they may be causing some fluctuations in the power supply which may be leading to the Bluesmirf shutting down.
I beleive this may be a highly unlikely reaon for the problem but you may want to try and eliminate this possibility.
Also check if the message that you are transmitting to reverse the motors is correct.
