Tug Captain's comment that my unit is aimed at "toy motor vehicles" is slightly off beam - I think he's referring to my "Programmable" unit (as Technobots chose to call it). This does ten different engine sounds of 'diesel' and 'petrol' character. Like the previous single voice units this WAS aimed at boats, but a guy wanted to use it in a Toylander 1/2 scale Land Rover (kids ride-in model) and after difficulties with adapting a servo tester driven by the throttle pedal to produce the requisite RC input signal, he appealed to me for help. So I did a MKII version with the user option to accept a potentiometer input as well. In announcing the MKII, Technobots obviously made play of this new feature, hence the confusion for those not aware of the previous MKI version.
Reading this thread, it seems the replies are talking about the single voice 'diesel' unit so those interested should carefully check all the units on offer at the Technobots site to be sure you are all talking about the same thing.
Fundamentally the single voice 'diesel' and 'petrol' engine sounds are repeated (plus 8 new ones) in the Programmable unit but the latter has the facility to adjust neutral, span, idling timeout, tickover, topspeed as well as having twin throttle inputs (sound follows whichever of the two is faster), an adjustable pitch horn and RC remote start/stop plus a (manual) volume control.
Currently I'm working on an improved version of the Technobots 'Combo' unit based on the Arduino Nano microcontroller which does everything the Programmable unit does except the twin throttle option (that requirement is neatly circumvented by a 'throttle out' connector on my rudder mixer which performs the same 'high auctioneer' function). However a new feature is a dynamic volume function - users can set one volume for tickover and another for top speed and subsequently the volume will change proportionally with speed between these two limits.
I've just designed a PCB for it and at this very moment am wondering how many to buy (they are NOT cheap in small quantity) so I wonder if I have any volunteer guinea pigs to swell the numbers to drive down the cost. Should the software change the Arduino Nano can be reprogrammed via its USB port - either a hex upload in your own workshop if you're a geek or f.o.c by me though you pay the postage. When I have some idea of the level of interest I can figure out a price. The PCB dimensions are 67x48mm and it's unhoused (fixing holes in corners)
Alan