Voice Recording On A Chip - Schematic & Pcb Artwork Wanted

[cobra148]

Thanks Hans.
I have looked at the boards in eagle,and can only say your very good at design.
This will be my 1st time with 2 sided board,so may need some guidence on the
correct way to go about it.

For instance, I need to see how top trace continues to bottom trace,e:g how
are they bridged together (is it with pins through the drill holes) ?.

Being my 1st time on 2 sided, I also cant figure how say IC1 TDA1905 legs
solder to the top trace,as well as bottom trace.

I sometimes miss the obvious, especially if I have not done it before.
So please forgive my question.

Yes hans I would like to go with this design, so any further build tips instructions please go ahead and post.
I will definately need a bag of switches, please advise if you are paypal member for payment and shipping.

I will e-mail my address to you through your hotmail,although it will say
my address on paypal notification, just let me know the total inc shipping
ok my friend.

best Regards

 

[Boncuk]

Voice recording chip

Hi Stuart,

if you follow a trace changing from bottom layer to top layer there is always a solder pad on both sides (via) to connect both traces by through contacting. Since you are going to make the PCBs yourself the easiest way is just a small piece of wire soldered from top to bottom in the via. The PCB layout is very narrow and the via size is 1.016mm with a drill size of 0.6mm.

I altered the layout in some details so you don't have to bother about proper connections from top to buttom simply you cannot solder certain components from both sides, e.g. the box header. A resistor can be soldered on top and bottom and serves as the small piece of wire you'd use for through contacting.

I will explain how to make a good double sided board an easy and cheap way in an email. (I used galvanizing in Germany, but here I can't get the chemical stuff)

Don't worry about the money for the switches. They are really cheap here and I won't charge you any money for them. Shipping will be far more costly than those few switches. When it comes to that just transfer the shipment money on my PayPal account. (account: hjzelec@freenet.de).

The screw terminals for the external switches have a pitch of 2.54mm (1/10"). Please let me know if you can get them in your country. Usual pitch is 2.5mm and mounted as one block you'll get into trouble using those missing almost 1/2mm of total length when fitting them onto the board.

Hans

 

[cobra148]

E-mailed you hans.
Thanks.

 

[leejongfan]

Hi all,
I am trying to build a voice record/playback using ISD25120P chip.
I constructed a circuit according to the sample circuit for Push-button mode in page 33. figure 7, datasheet except:
- 8 Ohm instead of 16 Ohm speaker.
- I did not have those 1 uF polarized caps
When in playback mode, I only hear some noise like when you hear from the radio. I think it means that the circuit work.
But I couldn't record anything, even if I used LM386 amplifier
I checked my circuit several times and couldnt find any mistake.
Really appreciated if anyone could help
Thanks!