Let's Make Robots!


Has anyone had any success programming the event phrases into the SpeakJet's EEPROM? I don't know if this is done via a PIC or right from my computer. The software implies that you load it onto the speakjet directly from the computer, but how would I do that? 

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Can you give me the link to the SpeakJet Yahoo Group?  Thanks!

 Aaron (aaron@zmm.com)

The SpeakJet Yahoo Group can be found at


Can any of the electronics wizards explain why there are two 27k resistors and two 0.01u capacitors in the diagram below betweeen pin 19 and the audio amp?

Balinese Archive - SpeakJet Circuit


I also now note Figure 1 in the SpeakJet manual shows a 50k pot between the SpeakJet and the audio amp. I have a 10k pot (as per the LM386 spec sheet). Would the smaller range of the pot explain why it seems to haveno noticeable effect?


The 27K resistors and capacitors are a filter to improve the sound quality. If you use different values than specified such as a 10K pot instead of a 50K pot then you cannot expect it to work properly. Since I didn't design the chip I can't give you more details.

I just rebuilt my circuit with the two resistors and three caps between Pin19 of the SpeakJet and the Amp. It's made a huge difference to the volume - much louder - and the trim pot now seems to have a small, but noticable effect.

I also tried the Bass Boost mod from the 386 spec sheet. It seems to reduce treble rather than increase bass. Still, if that's what you want, then it does the job.

I now have useful volume comming from my 2cm mylar speaker .


How do you connect a mylar to a picaxe

Hi calc

I've seen your posts in the other forum, can you post your code here, I want to try it and see what you mean with the decay? 


serout 0,t2400 (20, 96, 21, 114, 22, 88, 23, 5, 147, 159, 194, 134, 140, 8, 191, 162, 8, 169, 8, 128)

...which corresponds to "Hey Carl, welcome to the barbeque", but it only gets to second syllable before it slows way down. After a minute, it goes into demo. So I'm thinking i may have my wiring wrong. But it's late, so I'll have to check it (and probably be embarassed) later.



Check that you have connected M0 (Pin 13) to Gnd. I had it conencted to V+ for a short while and couldn't understand why I kept getting bursts of demo mode, when I was just running code that I'd tested before.



That code string simply says "welcome to the". But, it does it very nicely on my test rig.