Thread: DIY Picaxe Prop Controller. Compare with Picoboo Jr.!

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I know people have used the picaxe chipset as a prop controller before, but I wanted to emulate the functionality of the picoboo box controller. So I developed a "learn and play" controller. The picaxe chip will log the state of the input button, and then play it back on the output pin upon triggering. The video below shows a 08M2 chip with one relay but I also have a 14M2 chip that can support 4 relays.

The relay is a 5v 10amp. In the video you can see it controlling a 12v wiper motor.

I like the idea of the learn and play setup because it allows for programming the prop in real time, so you can get a real idea of what the timing will be like.



Picaxe Forum Thread

I will continue to update this thread as the project progresses.

Let me know what you think!

That looks great!
Can't wait to see the finished project. I'll definitely build one.

I'll also be watching this thread. I wanted to do a Picaxe project this year but unfortunately ran out of time. It's definitely on the list for the long cold winter months. I have the 08M chip, proto board and other stuff waiting patiently for me to get back to.

If you're familiar with picaxe, you'll have an idea of what I'm talking about, but there are some "quarks" with this set up.

First, there is only limited memory available on the picaxe chip. You have two options (without using external eeprom): the internal flash memory or the RAM. The internal eeprom lets you sample 256 times (for the 14M2 chip) and stays intact after the power is removed. This way utilizes the read/write commands. The RAM allows for 512 samplings but is lost once the power is removed. This utilizes the peek/poke commands.

The program logs the state of the input pin every 200ms. This means for internal flash memory you get 51.2 seconds of recording time. When using the RAM you get 102.4 seconds.

The next little quark is the resolution between pin states. Because I sample every 200ms, if the pin state changes quicker than that, the chip won't be able to resolve the change. Currently, because I don't need the full 102 seconds, I have changed the 200ms to 100ms in order to get better resolution.

If there is interest in it, I may consider getting some custom PCB's made once the design is finalized. I figure with boards and parts it'll still be half the price of the picoboo Jr. with double the relays.

Options I am still considering: External eeprom memory for increased storage that's not volatile. SD MP3 player; I have a USB/SD mp3 player board I got from MDFLY and I may tie that in so I have sound. I'll try and put together a video with the 14m2 chip with multiple relays this week.

I wish I understood half this stuff so I could develop one of my own controllers. Excellent concept - you geeks rule.

ChrisIsCreepin - I'm extremely interested in your awesome controller. Half the price!? Sweet! Twice the relays!?! Wow! I'd buy three when your able to produce, for sure. I'd love to sync up some homemade pirate cannons with fog machines and lights to a mp3 player soundtrack. Your controllers would work great! Thanks for the post.

The picaxe chipset and it's community is great. There are a ton of people willing to help you out if you get stuck. I found the chips extremely easy to get the hang out. The programming language is pretty basic (no pun intended). This was my first real picaxe project.

Here is the 14M2 chip controlling 2 relays. I didn't have enough room on the board for 4 relays, but once I get my larger board in, I will mock that one up too.

Will you need to program all the relays at the same time or can you program them one at a time?

@Halstaff Currently you need to program all relays simultaneously. The program works by assigning a number to a variable based off of the number of relays that are on. i.e: both relays off = 0, Relay1 on and Relay2 off=1, Relay1 off and Relay2 on=2, Relay1 on and Relay2 on=3. Then when triggered, the variables are read back and the outputs are defined based off of these numbers.

With 4 relays you have 16 possible combinations. So the program gets a little longer and a little more complicated. I'm sure there is another way to do this rather than spelling out all possible combinations, but I found it easier this way.