Tonight's project, a power supply (DC to DC converter) for my robot project. It must be able to power a USB hub. The hub in turn powers the Raspberry Pi Model A, WiFi dongle, a Webcam, and an Arduino board. The power supply should also provide power for the H-Bridge and motors.
The Arduino itself directly powers the servo, IR sensor, Sonar, Electronic Compass, and perhaps a 433 MHz radio.
The 7805 is rated for 1 Amps, I've got a resetable PTC fuse rated for 0.3 Amps, but I think I will replace it with a fast 1A glass fuse. I will also have 1N4001 to make sure the batteries are placed the right way, a LED to show power is on, and a on/off switch.
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| Power supply in parts |
The parts list
- Perfboard PCB
- DC connector
- Fuse holder
- 1 Amp fast fuse
- 220 uF electrolytic capacitor
- 10 uF electrolytic capacitor
- 2.4 KOhm resistor
- Green LED
- 7805 1 Amp
- 2.1 mm DC plug (for the USB hub)
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| Powersupply for my robot, First LED test |
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| Connected the power-supply to the hub. And the hub powers the robot and the Raspberry Pi |
When trying to boot the RPi from 9V battery the Pi reboots directly after the colored splash screen indicating that the single battery cannot provide the requested amount of power:
"Immediately after displaying the splash screen, the PI starts consuming a little more current, if the PI resets at that moment its an indication that the power supply isn't able to deliver the full current your PI requires" - R-Pi Troubleshooting
When connecting the powersupply to a battery-eliminator that can provide more current the pi boots up fine, so it is the single nine volt battery that is the source of the problem.
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| Robot batteries on the underside |
I connected it to the 6 AA battery pack on the underside of the robot and it booted up fine... Epic win!
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| Pi running and booting fun from the 6 AA batteries |
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