ATX powersupply for RPI
I needed a power supply for the RPI used inside my bartop arcade. An old ATX PS seemed to be the solution but it needed a little addon...
The ATX power supply has several voltages on its motherboard connector.
One of them is 5VSB which is a 5V present when the power supply is under mains voltage.
This 5VSB is used to power the microcontroler.
The role of the microcontroller is :
- to switch on and off the power supply when a push button is pressed.
- to switch off the power supply when the Raspberry Pi goes to power down mode (using a GPIO).
- to monitor the temperature of the RPI's microcontroler and activate a 12V Fan.
The RPI is powered by a µUSB cord and the board gives the opportunity to power an external 2.5" USB drive directly from USB (check my previous article "A Cloud in the Shape of a Raspberry").
This board is built around an ATTINY85.
The code is developped using Arduino libraries but under Eclipse IDE.
For doing this I have written a small utility which creates for you script files to compile the code under Eclipse but this is another subject...
One of them is 5VSB which is a 5V present when the power supply is under mains voltage.
This 5VSB is used to power the microcontroler.
The role of the microcontroller is :
- to switch on and off the power supply when a push button is pressed.
- to switch off the power supply when the Raspberry Pi goes to power down mode (using a GPIO).
- to monitor the temperature of the RPI's microcontroler and activate a 12V Fan.
The RPI is powered by a µUSB cord and the board gives the opportunity to power an external 2.5" USB drive directly from USB (check my previous article "A Cloud in the Shape of a Raspberry").
This board is built around an ATTINY85.
The code is developped using Arduino libraries but under Eclipse IDE.
For doing this I have written a small utility which creates for you script files to compile the code under Eclipse but this is another subject...
Discussion (1 comment)
C.D. Bradfield 2 years ago
1- uinfortunately the magazine Fig 5 has been cropped, losing the labels for X2-X4.
2- many years ago, I tried repurposing a PC power supply. I discovered that the regulation of the output voltages could be a problem. The PSU was designed, assuming a large load on the +5v output, lesser loads on +/- 12v. With a small load only on the +5v, other output voltages were unreliable. I would suggest a little caution.
2- many years ago, I tried repurposing a PC power supply. I discovered that the regulation of the output voltages could be a problem. The PSU was designed, assuming a large load on the +5v output, lesser loads on +/- 12v. With a small load only on the +5v, other output voltages were unreliable. I would suggest a little caution.
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Sebelec 5 years ago
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implant.png (5kb)
ClemensValens 5 years ago
Sebelec 5 years ago
ClemensValens 5 years ago
Sebelec 5 years ago
schimmi2 5 years ago
I have used it to power the Raspberry Pi and use one of its GPIO to Switch on the main Supply to power the heavy load. It is just another usecase for a ATX power supply in combination with a Raspberry Pi.
Armin.G 5 years ago
Uaaaaa, I see burning small copperpoor USB Cables taking the 30 Amps from the powersupply, when a shortage is made :-(
You should implement some fuses urgend !
May be one polymer ptc fuse per USB socket.
Regards
Armin
Dr. Thomas Scherer 5 years ago
I never would use that, even if I had an old ATX PS which I don't need for other things. It is just the opposite of "green".
Sebelec 5 years ago
Sebelec 5 years ago
I will soon post on the lab the board I've developped to control the joysticks and the marquee...Yes you can find on the web this kind of board ready for few euros, but it is not funny. Mine handles the buttons, the joysticks, 2 coin pushers and the marquee...
Dr. Thomas Scherer 5 years ago
Such an old PS may be a cheap solution if you have one laying around, it only gains efficiency for much more power. It would be a good idea to measure the relation of power in/out.
Jack JJo Jouas 5 years ago
PS:j'ai acheté il y a 2 ans ce produit pou realiser un chargeur 4 ports USB 5v.
Sebelec 5 years ago
Je voudrais juste préciser quelques points :
- tout d'abord, j'avais cette alimentation dans un vieux carton et plutôt que d'acheter un produit nouveau qui serait expédié de Chine, réutiliser l'alimentation était un challenge interessant et plutôt écoresponsable.
- la carte mesure la température du processeur pour déclencher un ventilateur (qui peut être soit du 5V soit du 12V).
- avec cette carte je peux utiliser un CDROM ET un disque dur externe IDE (besoin de +12V et +5V) (là encore de la récup).
- Lorsque la RPI s'éteint, l'alimentation entre en veille (comme un PC) en coupant les alimentations non utiles.
- enfin c'est un forum et un magazine de passionnés en conception électronique et même si ce projet te parait inutie, ce que je peux comprendre en fonction de ton besoin, j'ai pris du plaisir à le concevoir et à le partager pour les autres. Dans ma borne d'arcade il remplit son rôle à merveille, si cela peut servir à certain pour leur projet j'en serai ravi, pour les autres ...
Jerjer 5 years ago
Donc déjà merci pour l'exercice et ça va peut être me motiver à trouver un intérêt à de vieilles alims ATX qui traînent et prennent la poussière.
Concernant le rendement faible à ce niveau de charge, certes, mais la différence de conso de cette alim ATX VS une alim achetée exprès ne sera jamais défavorable par rapport à la dépense + livraison + fabrication de cette nouvelle alim.
Je serais quand même intéressé si tu arrives à mesurer la puissance d'entrée et de sortie de ton alim sur le +5V.
Bonne suite dans tes projets.