This is the first time I have ever taken a project, thanks to Pol. The client had admitted that this is a last minute job and therefore, the risks of failure (to me) is quite high. I have been given four days or less to come up with the goods. Since Pol trusted me on this job, I cannot let him (and my self-confidence) down.
The client needs a voice recording and playback feature on their Doll. Originally, the design requests for the feature to be put into the Doll. However, the Doll's costume has already been done and since it cannot be taken off, the only solution would be to place the electronics outside.
I have proposed to have the Doll placed on a small box-like base which would house all the electronics within and also added a figure stand on top of it. To sweeten the deal, I also proposed the novelty of having it being activated via remote control.
There are three electronic modules inside the base. The first is the voice recording/playback module, the voltage converter and lastly, the remote control receiver. Because this is a last minute job, I would need to used "off the shelf" items. I have most of the items on hand because I have been getting a lot of them from my favourite shop: WIZE Electronics. The only problem would be to integrate all of them together, something which is going to need some time.
Got the call fro Pol and he passed me his ex-colleague's contact number. Pol's ex-colleague then passed my contact to the client. By now, I am already thinking about the project and I roughly know what the client needs.
Not feeling well. Was sick since Sunday. Met with the client and discussed about the requirements. He passed the Doll to me and unfortunately, because the costume has been sewed on, there is no way to open the Doll without wrecking the costume. Therefore, having the electronics inside is now out of the picture. Located the remote control module and bought the figure stand in the evening. Started to plan the project and backups just in case.
|This is a single channel wireless remote. But when I look at the circuit board, it can house an additional channel. But then, I would have to change the transmitter fob. Still, it is a wonderful solution and has been in use in a lot of applications such as door access, electronics gates, and so on. What I am so happy about is, it can still work with a minimum of 8 volts even though its supposed to be 12 volts. I can take the main receiver module off and make my own but we're running out of time for this project.|
Went to Pasar Road to scout for some "off the shelf" solutions. Unfortunately, none of them fits the requirement which the circuit board is either too big or the circuit does not allow you to stop recording until the end of memory has been reached. So, I went to WIZE Electronics and decided to build up the voice recording/playback circuit from scratch. Spent the whole evening building the circuit using a prototype board but missing a few components.
|This solution I took from a toy is out. But it can definitely fit into the Doll. However, it would create new problems such as creating a flap or opening for the door for battery change, creating REC/PLAY buttons on the Doll and so on. Moreover, this toy can only record up to 5 seconds and the quality and volume leaves a lot to be desired.|
Spent the whole afternoon at WIZE and learnt a lot about the circuit and signal interference, thanks to Mr. Tan and his son. Got the circuit working, bought more components and also the base (box) for the Doll. Today is Saturday and shops would not be open tomorrow. Stayed until closing time as Tan Jr. was helping in getting me a set of backup components. Rushed back to re-create the circuit onto PCB stripboard. Recreated circuit is not working and unable to think clearly by four in the morning. Forced myself to sleep but with a heavy heart.
After much component swap, we managed to bias the microphone to an acceptable level with minimal interference. Also, a voltage regulator needs to be added as the chip's working voltage cannot exceed 6.5 volts. Note I used a lot of test cables and a prototype board since there are a lot of modifications to be done on the fly and the microphone is polarity sensitive too.
My second daughter's Birthday! Found last night's fault (missing power link). Created the base from as according to plan (from my head). Test fitted all electronics and made sure they're working when the base is closed. Wife is impressed. Met with client, showed the finished product and did some test recording. Suprised remote can work from quite a distance.
The design on the stripbaord is very different to the prototype board and therefore, before each component is soldered permanently in place, they must be checked since there are no backup components in my electronics box. Smelt a lot of solder fumes, started to get crazy thoughts....... like buying an MP3 player and stuff it inside the box.
One final look before I attach the figure holder and close the lid. You can see the electronics are very cramped in there. I had to use a toy's plastic to electrically isolate the remote control receiver as seen outside the box, on the table. In the rush, plugged the power the wrong way and blew the 6volt regulator> Replaced with a 5volt regulator and circuit is still working fine.
This is the finished product which comes with a 6 volt
power adaptor and two remote transmitters. With all the electronics
in there, there is no space for batteries but if this project was given a
timeframe of at least two months, I could reduce everything to almost the
size of the remote.
The tools I used were my tructy soldering iron, a glue gun, UHU glue, both digital & analogue meters, drill bits, protective plastic from a MacFarlane HALO blister pack, cutter, screwdrivers, etc. Since the Internet was down (which was a good thing otherwise I would be distracted and everyone trying to chat with me), I played some New Age and S.H.E. MP3s to keep me sane.
I did not get down to the car for the drill since I did not want to wake anyone up. So, for the rest of the night, I used my hands and gripped the drill bits to make the necessary holes. Come morning, I realised how much time I have wasted when I took the drill and made the remaining holes within seconds. Yeah, junkfood and other tid bits kept me awake.
I had Kristine test the product before getting it out to the customer