Registered: Dec 2000
Location: New York, NY
Posts: 63

I cant stand that the volume of my Prism's speaker is so low. I constantly miss appointments because I never heard the alarm I set. I want to make modifications but need some info. I e-mailed Handspring but was told to refer to their website. That was a waste of time. They only respond to registered developers. Anyone who can answer my questions will have my gratitude. The following is from my e-mail to them:

...One of your reps from Handspring Tech Support told me to look at the Handspring Developer Website. I checked out EVERYTHING including the hardware diagrams and every PDF file related to the Prism. I was unable to find any mention ANYWHERE of the piezo "speaker" that is used to create sound. I was looking for power and signal requirements of the piezo. Here's what I need to know. Please respond to EACH question so there is no confusion when I attempt my upgrades.

1. If I cut the piezo's wires from the connector attached to the circuit board and replace the piezo with a slim REAL speaker (like the TRG Pro PDA uses), will this work?

1a. If not, why?

2. If I can't use a speaker and MUST use a piezo as per question 1a, what power, signal and other specifications (such as size) must the piezo meet?

2a. Using the specifications from question 2, is it possible to use a louder piezo than the one that comes standard on the Prism?

2b. I was told by Handspring Support that the piezo "speaker" in the Visor Edge is ALOT louder. Can I use a piezo "speaker" from the Visor Edge in the Prism if I were to purchase one from Handspring?

2c. If I can't because the connector is different, can I just replace the connector?

2d. If I can't because Handspring will not sell me an Edge piezo, can I get an OEM version somewhere if you provide the specs?

3. Do you think I'd get any increase in volume if I were to remove the back cover of the Prism, remove the piezo, create a "speaker grille" by drilling a few small holes (each about the size of the reset hole) through the back of the case where the piezo's sound would pass and then replace the piezo and back cover?

4. If the answer to questions 2a and 3 are yes, can I combine both solutions to create maximum volume?

These questions are posted on several Visor related forums to maximize my chances at finding the answers. My apologies for wasting space.

Registered: Jun 2000
Location: Sunnyvale, CA
Posts: 216

I'll give this a shot, but I don't own either a Prism or an Edge...

1: No. A piezo speaker generates sound from voltage. A real speaker generates sound from current. A circuit that is design to drive a piezo speaker will hardly make any sound at all if you hook it up to real speaker.

2: I don't know since I've never designed with a piezo speaker. I do know that the voltage drive to the piezo speaker will likley be 3.3V because that is what the main Visor supply is. On the other hand, if Handspring designed in special driver circuit, the voltage could be higher. I doubt they did this because it adds significant cost.

2a: Should be. But the louder piezo speaker might be larger.

2b: I would think so. But you will likely not be able to buy just the Edge piezo speaker from Handspring.

2c: Wire cutters and a soldering iron will make this work.

2d: The best way to get an Edge piezo speaker, or to find out the specs, would be to open an Edge up and see if there is a part number and manufacturer stamped on the speaker. If so, just find out where to buy that part or one with the same (or better - eg louder) specs.

3: Yes. In fact I'm going to try this same technique on my Visor Deluxe to see if I can increase the volume.

4: Most definitely yes. If you do one modification, why not both?

One other idea is this: I designed a cellphone about six years ago. The speaker we used was a special piezo design that was very loud and reproduced sound in the 300Hz to 3kHz range (telephone bandwidth) very well. It was called a "reciever" - telephony talk for a speaker. I think the part was made by Murata, but it's been so long I can't be sure - and no, I don't remember the part number!

Hope this helps.

Registered: Dec 1999
Location: Connecticut USA
Posts: 2682

Continued here.

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