Help!
Gorilla
Posts: 16
I have finished my scrolling display project and I am ready to take the final step and order a printed circuit board. I am still designing the pcb and I am stuck.
I want to be able to plug it into the AC wall outlet and I want it to be able to run it on a 9v battery but I don't know what parts to add to the circuit board and I don't know how I should wire things up.
Do I need to add a voltage regulator on the pcb?
Do I need any resistors to protect the stamp?
The basic stamp 2p40 has a VIN pin what do I do with that pin?
What is the vdd pin used for?
I want to be able to plug it into the AC wall outlet and I want it to be able to run it on a 9v battery but I don't know what parts to add to the circuit board and I don't know how I should wire things up.
Do I need to add a voltage regulator on the pcb?
Do I need any resistors to protect the stamp?
The basic stamp 2p40 has a VIN pin what do I do with that pin?
What is the vdd pin used for?
Comments
1) Remember that a 9V battery has very little capacity compared to something like a 6V pack of 4 x AA or 4 x AAA cells. Look up the battery capacities some time on the Energizer website for example.
Do you want to use rechargable batteries? Do you want them to charge when a wall-wart is plugged in? How much current does your board require?
2) The Stamp has its own voltage regulator that can supply just slightly more current than the Stamp needs. What else needs to be powered from the 5V supply? If you need more than 50mA total at 5V, you need some kind of external 5V regulator.
3) Protective resistors for what? You haven't said what you're connecting to the Stamp. I know you have another thread somewhere, but you normally should have this discussion on that thread since it's a continuation of that design. Since you've started another thread, you should repost the schematic you're using or at least include a link to the other thread.
4) Read the description of the Stamp pins in the Basic Stamp Syntax and Reference Manual. There's an on-line copy included with the Stamp Editor. Vin is the input to the on-board voltage regulator.
5) Vdd is the output of the on-board voltage regulator and the input pin for regulated +5V if you're using an external voltage regulator. If you supply regulated +5V, you don't connect anything to Vin and the on-board regulator isn't used.