Tuesday night saw Derby Makers' inaugural Annual General Meeting take place at the historic Derby Silk Mill.
Lots of positive discussion was had and some exciting new developments regarding both the Museum and related organisations were talked about. Some forthcoming events were also outlined and gave rise to very enthusiastic brainstorming about impending project ideas.
One such idea was sketched out frantically around the AGM table (accompanied by lots of illustrative arm waving and silly gesturing). I am sworn to secrecy at the moment but suffice it to say that the remainder of this blog post is a tiny hint as to what is to follow...
The secret project requires an object to receive a simple set of on/off signals from a short distance away.
We decided that we wanted to keep things as simple as possible so I initially thought about using an old TV remote control as a means of sending pulses of light to the remote device. The several TV remotes that I tested (on my logic analyser) all produced a bunch of coded binary signals and would require a fair bit of programming to decypher. Nope, this hack would be more awesome if it were thrown together with minimal effort on things like that.
Radio control then presented itself as a possibility. Nothing fancy, of course, preferably something very small ...Something like this...
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This little gem was gathering dust in the lab and seemed perfect for the task at hand.
Basically it's a tiny RC car with 3-way steering and forward-stop-reverse motion. The mouse shaped thing is merely the shell that goes on top of the car to make it "fun to play with". In reality the novelty wears off in about 4 seconds, when you realise just how cheaply made it is.
What it does have is some nice binary signalling to hack into!
Close ups...
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The above pic is a close up of the receiver unit that lives in the car. The wires on the right side are (from top to bottom):
Black wire- battery negative
Magnet wire - steering coil (LEFT)
Magnet wire - steering coil (RIGHT)
The on-board battery is a tiny little 1.2c nicad rechargeable cell. This is charged by docking the car itself onto the controller handset by means of a pair of snap-on clips. Charging simply draws current from the pair of AAA batteries in the handset, and takes about a minute or so.
To be honest the quality of the product is higher than I had expected given the asking price of less than £10 when it was new about 6 years ago. The PCB is not bad, it's a 2 layer with PTH and has very few vias, indicating a fairly efficient board layout. The soldering is appalling, as you'd expect.
The plan is to connect the outputs of this simple radio receiver to a ATTiny85's ADC pin (via a resistor network) in order to provide the chip with user input so the chip can then ..... oh wait, that's a secret :)
I'm planning to put a bit of cleverness into the ATTiny's firmware to allow some "cheat-code" features... if you press the controller buttons in the right order then interesting things happen in the system!
The various bits of circuitry I've gathered together for this build (including batteries) weigh about 80 grams. Which is about as heavy as I want the electronics to get. I won't tell you why :)
I will build a little circuit that will allow this 1.2 volt circuit to be run from a main supply of probably 3.3 volts, which makes all sorts of things possible.
Watch this space!
Lots of positive discussion was had and some exciting new developments regarding both the Museum and related organisations were talked about. Some forthcoming events were also outlined and gave rise to very enthusiastic brainstorming about impending project ideas.
One such idea was sketched out frantically around the AGM table (accompanied by lots of illustrative arm waving and silly gesturing). I am sworn to secrecy at the moment but suffice it to say that the remainder of this blog post is a tiny hint as to what is to follow...
The secret project requires an object to receive a simple set of on/off signals from a short distance away.
We decided that we wanted to keep things as simple as possible so I initially thought about using an old TV remote control as a means of sending pulses of light to the remote device. The several TV remotes that I tested (on my logic analyser) all produced a bunch of coded binary signals and would require a fair bit of programming to decypher. Nope, this hack would be more awesome if it were thrown together with minimal effort on things like that.
Radio control then presented itself as a possibility. Nothing fancy, of course, preferably something very small ...Something like this...
This little gem was gathering dust in the lab and seemed perfect for the task at hand.
Basically it's a tiny RC car with 3-way steering and forward-stop-reverse motion. The mouse shaped thing is merely the shell that goes on top of the car to make it "fun to play with". In reality the novelty wears off in about 4 seconds, when you realise just how cheaply made it is.
What it does have is some nice binary signalling to hack into!
Close ups...
The above pic is a close up of the receiver unit that lives in the car. The wires on the right side are (from top to bottom):
Black wire- battery negative
Magnet wire - steering coil (LEFT)
Magnet wire - steering coil (RIGHT)
Blue wire - motor power A
Red wire - motor power BPair of magnet wires - common GND for steering coils
Red wire - battery positive
The on-board battery is a tiny little 1.2c nicad rechargeable cell. This is charged by docking the car itself onto the controller handset by means of a pair of snap-on clips. Charging simply draws current from the pair of AAA batteries in the handset, and takes about a minute or so.
To be honest the quality of the product is higher than I had expected given the asking price of less than £10 when it was new about 6 years ago. The PCB is not bad, it's a 2 layer with PTH and has very few vias, indicating a fairly efficient board layout. The soldering is appalling, as you'd expect.
The plan is to connect the outputs of this simple radio receiver to a ATTiny85's ADC pin (via a resistor network) in order to provide the chip with user input so the chip can then ..... oh wait, that's a secret :)
I'm planning to put a bit of cleverness into the ATTiny's firmware to allow some "cheat-code" features... if you press the controller buttons in the right order then interesting things happen in the system!
The various bits of circuitry I've gathered together for this build (including batteries) weigh about 80 grams. Which is about as heavy as I want the electronics to get. I won't tell you why :)
I will build a little circuit that will allow this 1.2 volt circuit to be run from a main supply of probably 3.3 volts, which makes all sorts of things possible.
Watch this space!