DIY Watch

I’ve been making a DIY watch using the MSP430 and a cheap display. It’s quite basic right now, but I’m planning on making the firmware better. It uses a surface mount MSP430 value line.

I’ve done some work on getting a Telit GSM module inside a watch also, but this one here is just a basic version. I had a voucher for a purchase at Shapeways that ran out this month, so I’ve ordered the case from them. That’ll allow me to compare quality differences of my Makerbot and the Shapeways commercial printers.


Play time counter with MSP430 and launchpad

We have decided to just buy one DS, but we have two kids. When we’re in the car, there’s a constant question of when the ‘swap time’ is. So that we don’t have to keep track of time ourselves, I made a watch that counts down from 10 minutes and then plays a sound. It uses a Powertip PE9665ARF-001 display to show the remaining time, and an MSP430 value line MSP430G2452 MCU.

It’s of course silly to make something like this, but it’s fun.

The PE9665ARF-001 display is really cheap (only a few dollars) and uses a Sitronix ST7576i I2C driver. It’s a really nice display and works brilliantly. Most importantly it’s super cheap, much cheaper than the other displays from Sparkfun or similar. I’ve bought it from Arrow.

I’ll post a picture later when I’ve put it in a box, but the following is a picture of two prototypes, one on a breadboard and one on a prototype board (this is the one I’m going to print a case for).

Infrared toy gun ‘lazer phaser’

I got the idea that it’d be fun to make an IR driven toy gun, and sensors that you can put on your body. Then make 10 of them and run around shooting each other. There are several commercial versions of these devices, and its quite a common team building exercise for companies. But it should be easy to make something like this DIY.

So I designed a simple circuit based on the MSP430 value line using the TI Launchpad. It’s a cheap MCU that’s relatively easy to program. Maybe not as easy as Arduino, but much cheaper.

But then I started wondering about the ‘moral’ implications of this. I don’t really want my kids running around shooting each other. I’m not the kind of father who wants to buy gun toys for my children. But is it OK to make it? It sure is fun, but is it right? I’ve got a working prototype of it, but I’m not sure I’m going to proceed making it. I was planning on printing the gun itself on my plastic printer. Maybe I could find some alternative, less agressive angle to the project. But I’m not quite sure what it should be. I certainly could make it look different from a gun, but would that help?

I’ve got C-code for the MSP430 that receives coded IR signals and plays the buzzer. When the button/trigger is pressed, it sends out a coded C signal and plays a short lower tone. The pipe is used to concentrate the IR light, and seems to work ok. The IR receiver is from Sparkfun, and works REALLY well. But it’s a bit expensive, so I’ve ordered some cheaper ones to try out. I’ve only tried it indoors. I guess it might not work outdoors.

Note: I’ve now also tried it with the IR RX Vishnay TSOP31238, which also works well. It’s a through-hole component and costs a couple of dollars. You need a pull-up resistor on it, and preferably an extra capacitor + resistor to filter the power.

Below is a picture of the components soldered together. I haven’t actually made the gun itself yet, due to my doubts about the correctness of making toy guns that lead to quite realistic killing games.

MSP430 Launchpad RF based motor controller

There’s this kid who wants to control a tank from his standard remote control, but it’s been difficult to find the right parts at the right price, so I made a component for him.

It’s basically a motor controller, powered by an MSP430 that takes PWM input from a standard remote control’s receiver. It can drive back and forward. It’s based on the cheap value line MSP430 that comes with the Launchpad.

It receives the two PWM signals from a standard RF receiver, takes the time of the PWM pulse the receiver sends (typically to a servo), calculates whether it should be moving the motor forward or backward, generates two new PWM signals and control signals for a cheap motor controller called L293D to drive the two motors of the tank. It can go backward and forward. I’ve made code examples that uses two sticks, one for each motor, and one that has a more traditional left, right, forward, backward control. The MSP430 code is posted below. Feel free to use the code as you wish. Give me credit if appropriate.



Continue reading MSP430 Launchpad RF based motor controller

Playing with wireless

I got hold of a Texas Instrument evaluation kit of the CC1110 chip. It’s a wireless chip that’s programmable and flexible both in terms of frequencies, codecs, packet handling etc. I’ve played with it quite a bit, and you can really have so much fun with it. I’m impressed by the capabilties and flexibility! TI also offers a free communication stack that they call SimpliciTI, which handles quite advanced scenarios and networks.

The CC1110 comes with a microcontroller, but there are simpler versions of the chip without the MCU also. Seedstudio has an Arduino version Atmega board with the CC1101 chip on it. Looks like quite a nice product at a reasonable price, given that it’s an arduino board with wireless capability. It’s really small. The call it RFBee. I haven’t tried it though. If you have any experience with it, let me know.

There’s an introduction video of the CC1110 mini development kit on the product page that I really recommend. The CC1110 is designed by TI in Norway. There are so many application areas for this type of solution. I’d like to put it onto one of my robots, but there are many other ideas also.